Green tech & greener living

Updated on 14/11/24 by Abby_OVO Check out our dedicated RTS FAQs page for more information. Updated on 10/1/25 by Blastoise186 Updates to Load Managed Areas have been added RTS Shutdown Update July 2024 Hey! The name’s 186, Blastoise186 and I’m one of the Forum Volunteers who you’ve maybe seen helping around here. I’ve been working with OVO to get the most up to date information possible for you and they’ve passed over the following helpful updates and details. One of the recent hot questions we’ve seen on the Forum (for a while now) is what’s happening to RTS meters. The RTS (Radio Teleswitch Service) is shutting down soon, which especially affects complex ones like THTC (Total Heat Total Control). I’ve covered this before in one of my older posts linked below – so check that out if you’re interested in why this is happening. That post already has many questions covered, so this one will focus purely on the next steps. Radio teleswitch (RTS) shutdown sunset FAQ If you’re interested in what all the different meter types are/were - just ask below. Not sure if you’ve got RTS? No problem – give OVO a ring and they’ll be able to let you know. You can reach out to them here. All caught up? Great, let’s get started on this latest update. This is the final piece of the puzzle - the hot off the press information about exactly what’s happening next. I’d like to apologise for the extended delay in getting this out. While I can - and do - act independently of OVO, such critical content like this still has to be reviewed and approved before it can go live to make sure it’s as accurate as possible. So without further ado, the big question… I’ve got an RTS Meter, what are my options for smart meters? Good question – as you may know, these meters can be pretty complex, but OVO have spent a good amount of time updating their systems to manage this change for their customers. I’m pleased to finally reveal what OVO’s plans are for everyone with an RTS Meter, whether it be Economy 7, Economy 10, THTC (Total Heat Total Control), Total Living Control, Standard Economy & Heating Load, Heatwise, Storage Heating Control, Flexiheat, Superdeal or basically any other RTS Meter. The long story short version is exactly what many of you wanted to hear - OVO will be contacting all RTS customers to sort the change to a non RTS meter. Even better, since everything will run locally and be controlled by the meter itself, your heating and hot water will continue to work even if the signal to the meter temporarily drops out. But what will you get? If you’re ready to upgrade and your meter is listed below as upgradeable, check out smart-booking.ovoenergy.com With another supplier? Please contact their customer service team for this as OVO can only upgrade meters belonging to OVO customers. Affected OVO supported RTS Meters/Tariffs If you AREN’T in a LMA (Load Managed Area*) - * A Load Managed Area is an area that's not as easy to maintain, like small islands or densely populated communities Economy 7 Available now! All customers with an Economy 7 (both RTS and Non-RTS) are eligible for smart meters. Everything else will stay the same - it’s just a straightforward meter swap in 99% of cases. Economy 10 Available now! OVO has just started to roll out Economy 10 support on smart meters. You should have already had a letter to arrange this change, if not, give OVO a call on 0330 303 5063. All other RTS meters (THTC, Superdeal etc) Available now! Here are the 2 possible routes you could go down. Available now! Good news! In this situation, you can go for Economy 7, Economy 9, Economy 10 or a single rate meter - totally up to you. Your letter will invite you to call OVO’s specialist team who are on hand to discuss the set up within your property. They’ll help you come to a decision that best suits your lifestyle. As part of the process, your THTC meters will be taken out and replaced with a shiny new smart meter (where possible) running on whichever tariff you picked. If you ARE in a Load Managed Area Available now! Please wait for OVO to contact you! OVO has informed me that THTC is now fully ending - even for Load Managed Areas - so you’ll be contacted regarding your options. Please consider your options carefully as it’s important you make the right choice. RTS Meters/Tariffs from other suppliers No details yet - feel free to help me build this out. If you’re with any other supplier and have info on what’s happening to your meter, feel free to post the details below and if it looks good, I’ll add it here - with full credit of course. What if I don’t want a smart meter and/or refuse to have the upgrade? If you don’t want the upgrade, then the RTS Service will eventually end regardless, and I’m really sorry, but I can’t guarantee what’ll happen to your heating and/or hot water, so I strongly recommend against taking that risk. These changes must happen and must happen soon. All I can say is that many of these RTS Meters are getting older now, and while the designers did include fail-safes to cover RTS Service outages, these were only designed for short-term outages - not a total and permanent shutdown. Just as I can’t guarantee what’ll happen to your heating and hot water, OVO can’t guarantee how long the fail-safe will last for - or if it’ll even work at all on your specific meter. Forum Volunteers on The OVO Forum may also be unable to provide advice and support for these meters post end-of-life to the same extent as we have previously, which means we’ll probably recommend you go direct to smart meters. We’ll still try to help out if we can - but our options would be limited. If you have any further questions, please do leave a comment and one of the OVO moderators will chase this up for us.

We'll be in touch soon with Charge Anytime customers about some changes to our T&Cs, which take effect on 15 April 2025. If you haven't heard from us yet, don’t worry—you’ll receive an email or letter by 31 March. Your smart charging rate of 7p per kWh will stay the same. You don’t need to do anything - you can keep using Charge Anytime as normal. The changes are in section 4 & 6 which cover Flexibility Services and how to pay. Section 11 is new, which covers our Fair Usage Policy. You can find out more about our Charge Anytime add-on terms and conditions on the website: Charge Anytime Terms (Current) Charge Anytime Terms (From 15 April 2025) Our FAQs have more information about these changes You’ll find more information about Charge Anytime in our Topic Hub: Useful Links: For our compatible chargers, here's the link to find out more . For our list of compatible Charge Anytime EV’s, here’s the link to find them . How to get in contact with the Charge Anytime team: Charge Anytime - 0330 175 9678 (Option 1 new customers/option 2 existing customers) chargeanytime@ovo.com

With the raft of online apps and services now in everyday use, I had begun to get frustrated that for some simple things (like thermostats, energy usage and security cameras) it was necessary to open a whole array of different programs. I stumbled across the concept of gathering these together under one service and now have a very easy, comprehensive option via something called Home Assistant (HA). (available on mobile app and pc) Although it has been many years since I did any real programming, I decided to try out this system and have found it a lot easier to put together and operate than I expected. First of all, I need to say that it is often not totally without cost. The system can be run on an existing computer but as the service really needs to be running all the time, most people tend to use some sort of minicomputer. I used something called a Raspberry Pi. This is a small electronics board – which can be bought as a full system or piece by piece – which links to your broadband router and subsequently the other services which you are running on the same network. For some of the services, there is an ‘auto-discovery’ mode which searches for Bluetooth or Wi-Fi signals and offers these to link to your device. Once you begin to have some options to look at, the next thing to consider is what sort of view or ‘Dashboard’ might be useful. There are multiple designs ready to be populated and you can choose several which can be chosen depending on what you want to view. Ultimately, you will settle on a default view which will be ready when you open the app. These can all be changed as much as you want as you discover new items to add but at present, I can see a whole host of sensors I have around the home including; Electrical import/export, Gas usage, Tariff values (at time of use), Temperature and Humidity (in various rooms), Solar PV generation, Battery storage levels, Mains Voltage and Frequency, Doorbell cameras, Key appliance operation (Washing Machine, Dishwasher etc). All of these can be monitored and, in some cases, even controlled as you might want to automate usage at cheaper energy price levels. There’s lots of helpful information available via a user and programmer community and it becomes a fun thing to see what else you can add to the system.

Updated on 11/03/25 by Bradley_OVO It's an exciting time in the EV and Solar market for customers. We're looking to get some feedback from customers who have an Electric Vehicle and Solar Panels. We currently offer Charge Anytime to customers with Solar Panels via a solar and Charge Anytime compatible charger. See a list of our chargers here and expand by pressing “+” to see those marked as solar compatible. We understand that some customers may have a different charger that is not on our list, so we would love to get feedback from you if you have been using Charge Anytime via a compatible Electric Vehicle and have recently installed solar or are considering installing solar panels at your property. Currently customers with that use Charge Anytime via a compatible Electric Vehicle can’t continue to use this service if they install solar. This is because the version of Charge Anytime that is via a compatible Electric Vehicle works due to the charging information that is sent from the car to us so we know how many kilowatt hours (kWh) of electricity have been used in each charge. Unfortunately, this method is not able to tell us whether the electricity used was from the grid or from the solar panels or storage battery in your home. For this reason we cannot currently provide this version of Charge Anytime to customers to get the discounted rate. We’re looking to solve this and we’d like you to take part in some research. Are you eligible for this research? You’d need to either: Currently be using Charge Anytime via a compatible Electric Vehicle and at the point of considering installing solar panels at your property. Currently have solar panels already installed and have an Electric Vehicle on our list here, but a different charger that means you cannot currently have Charge Anytime with your solar If you’re interested in taking part please let us know in the topic comments below and one of our forum team will be in touch via private message ! 🙂

What is it? We’re launching the UK's first nationwide heat pump flexibility trial, where heat pumps automatically reduce energy use during peak demand without affecting your comfort or heating. This trial will help us understand how we can use smart tech to improve the grid for a greener future. We'll be offering this trial from mid November throughout winter . We’ll be collecting data about energy consumption and how this level of flexibility impacts customers. We’re working with Nesta , the UK’s social innovation agency. Nesta’s aim is to find new ways to tackle society's big problems in education, the environment and health. Customers who take part in the trial, which includes completing a few surveys and interviews, will receive a £100 shopping voucher from Nesta at the end of the trial period. Who is eligible? To take part in the trial customers will need to have a compatible Vaillant aroTHERM 3 post 2016 or an aroTHERM Plus heat pump with a connected myVAILLANT Connect internet gateway. Entry to the trial is by invitation only. You can apply to join the Trial by completing the form linked from your OVO invitation email. You’ll also need to be signed up to our Heat Pump Plus tariff and be an OVO customer. You’ll also need to agree to OVO controlling the temperature of your heat pump remotely during the trial period. What will you need to do? You'll be asked to provide feedback during the trial period so we can see how effective it is. If you take part, you’ll get a detailed survey before and after the trial, and then short weekly questionnaires. You might also be invited to take part in interviews. What will you get? You’ll get a £100 gift voucher for taking part in the trial and giving us your feedback. Any further questions, please let us know below.

I am not a biologist; in fact it is nearly 50 years since I passed my Biology “O” Level. HOWEVER I would like to be re-assured that if I make changes to my heating system I will not compromise my family’s safety and well being. The following I have gleaned from various sources on the Internet. If you disagree great, but PLEASE supply the basis for your differing view. I’m afraid “a mate down the pub said” will not wash. What is Legionella? From the NHS website: Legionnaires' disease is a lung infection you can get from inhaling droplets of water from things like air conditioning or hot tubs. It's uncommon but it can be very serious. You can get Legionnaires' disease if you breathe in tiny droplets of water containing bacteria that cause the infection. It's usually caught in places like hotels, hospitals or offices where the bacteria have got into the water supply. It's less common to catch it at home. Where does it come from? From the CDC Website: Legionella bacteria occur naturally in freshwater environments, like lakes and streams. Generally, the low amounts of these bacteria in freshwater don't lead to disease. However, Legionella can pose a risk to health when it gets into building water systems and grows (increases in numbers). How does it grow? The bacterium is adapted to take advantage of a warm blooded host, so it is not surprising that it likes warm damp environments. Like Goldilocks it likes it not to warm and not too cold, not too acid or alkali, and it like to be left undisturbed. The Heat Geek provides a much better introduction than I can (and with much better graphics) so have a read of his article. I found it quite difficult to actual find information on how fast Legionella bacteria can grow. I found two sources. The first links to a no longer available blog. The second a paper is on researchgate.net Both seem to point to the bacteria doubling every 8 hours (10 times per day, 1000 times every three days, a million times per week!). So it is easy to see that a stagnant tank of water, sitting at the ideal temperature (around 40°C) with ample nutrients and the correct ph will become a breeding ground for the bacteria. Will my low temperature heating make this worse? Well yes, and no! There is a belief that in the past we set our hot water cylinders to 60°C and all was fine. However a survey by the Department for Energy security and net zero showed that few installations actually operate at 60°C. So in reality many existing systems could have had problems. However it should be recognised that fitting a larger cylinder (fewer volume changes per day) filled with cooler water should increase the likelihood of Legionella bacteria growing. Is there legislation? Again yes and no. The current legislation applies to industrial and commercial installations but is not strictly applicable to domestic installations. The building regulations (part G) specify maximum water delivery temperatures to prevent scalding. These limit the delivery water temperature to 60°C or even 48°C. Is my copper cylinder safer? Not really. It is true that copper (and silver) ions inhibit and destroy bacteria, but the required ion concentrations are not present in typical copper cylinders or pipe-work. (New) copper pipe is often cited as the best option for pipe-work, however the advantages of copper appear to result from the smooth nature of the pipe-work and not its bactericide properties. After a few years the build up of oxide or calcification removes copper’s initial advantages. Should I use a pasteurisation cycle? Advantages: Resets (most) of the cylinder contents to sterile. Remember that the coil and/or immersion heater doesn’t reach to the bottom of the cylinder. A 200l cylinder may only have 180l of usable hot water; the remainder sits below the coil/immersion. Disadvantage: One day a week you get really hot water. Don’t forget that if the turnover of hot water is small, bacteria will still grow (from a lower starting point?) throughout the period between pasteurisation cycles. Should I worry about my Combi boiler? Not really. The stored hot water volume in a combi boiler is tiny by comparison and is basically flushed through every time you run any hot water. What’s the answer? Sorry I don’t have one! Heat stores seem to be one solution, since they have small delivery volumes and hence rapid water turn-over and flushing. BUT to achieve satisfactory performance many stores needs to operate at around 70°C, so there wasn’t an issue anyway! Sizing hot water cylinders to match daily demand would ensure frequent flushing of the cylinder, but regulations seem to require cylinders to be sized for the property and potential occupants rather than the actual occupants. So empty nesters and retirees are often persuaded to have much larger cylinders than they actually need. The Heat Geek mini store seems to offer one option, but I would like to see a larger version and more “scientific” tests.

The Install Week On the lead up to our installation date for our Heat Pump (HP), we had everything in place: Space outside clear for the heat pump itself Internal loft space for the pipework and any system parts A clear space inside around the existing boiler for removal Storage space for the pipes, insulation and other equipment (being delivered on the first morning) I got a text message from the lead installer on Sunday evening letting me know that he would be arriving at 8am on the Monday morning. He was actually early and supervised the off loading of the delivered equipment. This can take a little time as there is often quite a lot of items alongside the heat pump itself which need agreeing as scheduled items and delivered. Other trades were due shortly and so we walked the install route around the property from the HP position, through the loft access, existing pipework, boiler, radiators (6 out of 12 to be replaced), gas supply point and electricity supply. One of the things I particularly liked was the willingness to listen to options. For example, I had been exploring the possibility of a different route for the main power cable for the heat pump compared to that discussed on survey. The plumber and electrician arrived shortly after this and set to work – first task, drain down the heating system and identify the radiators for swapping out. The gas engineer was due to arrive on the second day but as the team were ready to remove the old boiler, they got in touch with a nearby colleague and the boiler was taken out and the gas capped. So by the end of day 1, things were moving and there was no boiler and no hot water (the team had brought electric heaters to help heat overnight. Top left - void under house (cable run option) Top right - suggested position for HP Bottom left - hot water tank position Bottom right - first cable and pipework to HP Day 2 and Day 3 were similar in operation and by this time much of the pipework was in place (but not lagged) and the radiators were almost done. While much of the install was step by step, the team worked well together so that any needed work was done (plumb, cable, power, test) for each section to be completed before moving on to the next. Originally the cabling was due to follow existing primaries into the loft and then out to a small distribution board for connection but as I mentioned earlier, the property is built with a void underneath (local geology) and as this looked to be a straight route from incoming power to HP location, I suggested they try to feed the cables through the void. This was eventually successful but it did take a few floorboard removals to stop snags on the way. The heat pump itself was needed to be carried into position – quite a weight. We have gravel across the front of the property and the team did not have any mechanical lifting device anyway so they carried it between them around from the delivery location to the installation position at the rear. By the end of Day 3, much was done but the final wiring to the HP was not completed and so we remained without heat and hot water for another day. The hot water tank does have an immersion heater built in and I had expected that to be available mid week but I understand that the control for this is via the HP and so as the wiring was not in place, neither was power for the immersion option. Day 4 was taken up checking all joints, powering and running the system and then lagging. Each part of the system is checked individually and then full control. This type of set up defaults to Hot Water and once that is up to temperature a diverter valve switches the hot water to the heating loop and radiators. A look through the operating system with its schedules for heating and hot water led me to get a few things initially in place and everyone was expecting to be finished – the lead installer was due early on Day 5 to ensure everything was ok. I woke up in the early hours of Day 5 as the HP sounded to be working full out. The house temperature had also risen to 23 degrees C despite the overnight setting being 18. At that time of the morning I was not fully ‘with it’ and so eventually after a couple of system resets, I turned off the Hot Water as that appeared to be the only thing which allowed the HP to get back to a normal operation. Once morning arrived fully, our lead installer drove up and I greeted him with the news of the overnight problem. Calling the electrician to check all the connections, terminals etc., it was finally concluded that the diverter valve was faulty and would need replacing. They located one about 45 mins drive away and set to collect and return. It was this valve which was open to the heating loop although the system was calling for hot water, hence the issues with the higher overnight temperature. Well on return, the new Honeywell valve was fitted and the system tested. It all worked. So all in all, an interesting installation week. Obviously there is a need to be aware of the potential length of the install plus the lack of heating and hot water for at least some of the time. Something to be aware of. Now to explore the control options and get it set up how I want (See my pre-install experience here)

We’ve partnered up with Volkswagen Group UK to offer up to 30,000 free EV miles over 3 years when you buy or lease a fully-electric vehicle from a registered Audi, CUPRA, Skoda, or Volkswagen dealership after 1 July 2024. You can add Charge Anytime to any OVO energy tariff and enjoy: Up to 10,000 free miles when you first add Charge Anytime. Up to 10,000 additional miles each year for two years when you stay with Charge Anytime1 Offer terms and eligibility apply. Compatible EV or charger, and smart meter required for Charge Anytime . Who’s eligible for this offer? To be eligible for the 30,000 free miles, you must: Buy or lease a new fully electric vehicle from Audi , CUPRA , Skoda , Volkswagen or Volkswagen Commercial Vehicles . The vehicle needs to be ordered between 1 July 2024 and 31 May 2025 and purchased at a participating dealership through Retail, Contract Hire or Motability. Be an OVO energy customer Have a smart meter set up with half hourly read frequency to be eligible for Charge Anytime. Don't have one? Get one installed at no extra cost . Read our full offer terms and conditions . How do I sign up and claim the 30,000 free miles offer? For more details on this offer, check out your vehicle landing page below: Audi owner CUPRA owner Skoda owner Volkswagen owner Volkswagen Commercial Vehicle owner If you don’t have an EV yet, you can still bank free miles with Beyond Waiting for your new EV to arrive? Or looking to go electric at some point in the future? With our rewards program Beyond, you can bank even more free miles while you wait. Unlock Beyond for free and bank up to 150 miles a month. That’s 100 free miles a month for being an OVO energy customer. And an exclusive 50 free miles a month extra for buying a new Volkswagen EV.2 Access exclusive discounts and ways to save over £1,6003, plus partner offers, tailored energy insights, and more. To unlock Beyond, you'll just need a smart meter, to pay by Direct Debit, and to have the OVO app. Download on IOS Download on Android 1 Offer open to new or existing customers of OVO Energy who: (1) are UK residents excluding Northern Ireland, 18+, (2) have purchased/purchase a brand new fully electric vehicle from any Volkswagen dealership through Retail, Contract Hire for Motability between 1st July 2024 and 31st May 2025 (3) activate OVO Energy's 'Charge Anytime' and (4) have not claimed 'free miles' under a previous Volkswagen Group or OVO promotion. To activate 'Charge Anytime', the customer will need a compatible EV charger or electric vehicle (for a list of compatible chargers and vehicles please see here ). T&Cs apply to OVO Energy's 'Charge Anytime', see here . Offer valid on new Retail, Contract Hire and Motability sales only, where order was placed from 1st July 2024 to 31st May 2025. Offer subject to availability. Domestic charging only. To receive miles, the customer must claim by signing up to Charge Anytime and submitting their vehicle order number within 3 months of vehicle handover. Customer will receive the first 10,000 free miles as a credit on their OVO Energy account within 60 days of Charge Anytime sign up. Customer will receive an additional credit worth up to 10,000 free miles on the next two anniversaries of joining 'Charge Anytime' so long as they remain an OVO customer with 'Charge Anytime' activated. In addition to the up to 30,000 mile offer: for each year the customer remains on 'Charge Anytime', they will also receive a credit on each anniversary of joining 'Charge Anytime' worth up to approximately 1,000 free miles. This will be paid for a maximum of 3 years. Mileage calculations based on average efficiency, weighted in line with brand electric vehicle volumes, of 3.3kWh/mile across the Volkswagen Group model range (for all brands). Since this is an average, the efficiency of individual models may be less, which would mean the customer receives fewer than the maximum stated free miles. The efficiency figure is also based on standardised test data after the battery had been fully charged (to 100%) and may not reflect real world driving. Actual efficiency differs depending on multiple variables, including selected vehicle and configuration, accessories fitted (post-registration), variations in weather, driving styles, route conditions, speed, vehicle age, battery age and temperature and vehicle load. The actual number of free miles the customer receives may be less than the maximum stated miles and will depend on the actual efficiency of the selected vehicle in the real world. Offer is for an estimated number of free miles calculated on the basis of the costs to the customer when they 'smart charge' using 'Charge Anytime'. Electric vehicles require mains electricity for charging. For the latest information, including official WLTP range and power consumption data for the selected vehicle, please visit Volkswagen . We reserve the right to make changes to the Offer and these Terms at any time. For full Offer terms and conditions, see here . 2 Open to new or existing customers of OVO Energy who are GB residents, 18+. Excludes Northern Ireland. Offer enables non-EV drivers to "bank" free miles on a monthly basis, which they can then redeem at a later date if they go on to purchase a qualifying electric vehicle and activate OVO Energy's 'Charge Anytime’. To participate, you must (1) download the OVO App (compatible smartphone required) and (2) activate OVO Energy's OVO Beyond and EV Reward Offer. You can then bank miles through the OVO App. All customers will be able to bank up to 100 miles per month under the EV Reward Offer for a maximum of 24 months (i.e. up to a total of 2,400 free miles), with banked mileage shown in the OVO App. Customers who then purchase a brand new fully electric vehicle from Volkswagen after the 1st July 2024 through Retail, Contract Hire or Motability will be awarded up to an additional 50 miles for every 100 miles banked through the EV Reward Offer. Banked mileage and the additional miles awarded will be redeemed as a monetary credit to your Charge Anytime account, within 90 days of activating Charge Anytime. Credit can be used to charge your vehicle providing "free miles" of range. Banked mileage must be redeemed within 3 years from the end of the 24 month accrual period. Once expired, the banked mileage and the additional miles awarded will be lost. To activate 'Charge Anytime', you will need a compatible EV charger or electric vehicle (for a list of compatible chargers and vehicles please see here ). T&Cs apply to OVO Energy's ‘Beyond EV Reward’ (see here ) and 'Charge Anytime' (see here ). Offer valid on new retail and retail contract hire vehicles only, where order was placed after 01/07/2024. Not available for business purposes. Offer subject to availability. Mileage calculation based on average efficiency, weighted in line with brand market share, of 3.3kWh/mile across the Volkswagen Group model range for all brands. Since this is an average, the efficiency of individual models may be less, which would mean you receive fewer than the maximum free mileage. The efficiency figure is also based on standardised test data after the battery had been fully charged (to 100%) and may not reflect real world driving. Actual efficiency differs depending on multiple variables, including your selected vehicle and configuration, accessories fitted (post-registration), variations in weather, driving styles, route conditions, speed, vehicle age, battery age and temperature and vehicle load. The actual number of free miles you receive may be less than the maximum stated miles and will depend on the actual efficiency of your selected vehicle in the real world. Offer is for an estimated number of free miles calculated on the basis of the costs to the customer when they 'smart charge' using 'Charge Anytime'. Amount of credit you receive will vary depending on how many free miles you have banked and the current Charge Anytime rate at the time you redeem your free miles up to a maximum redemption value of 14p/kWh. Electric vehicles require mains electricity for charging. For the latest information, including official WLTP range and power consumption data for your selected vehicle, please visit Volkswagen’s website. For full Offer terms and conditions, see here . 3 Customers could save up to £1,617 with discounts on a range of products and services. Discounts will be in the form of a bill credit paid to your energy account after a one-time purchase of specific products, or a discount at the point of purchase. Current offers are: redeeming 2,400 EV miles collected with EV Reward; up to £35 bill credit for an EV charger and subscribing to a Charge Anytime tariff; 5% off a solar panel installation - this is £535 based on average order value though actual amount dependent on nature of install; a £85 discount on a home energy assessment with our Energy Experts (OVO Beyond cost £15, retail price £100); a tado smart thermostat for £96 (a saving of £103.99 discount on manufacturer’s recommended retail price of £199.99); £500 off a new boiler install; a free boiler service with retail price of £84; 50% off boiler plan at the complete cover tier equates to £96 in one-off saving. By subscribing to Power Move customers could also earn up to £10 credit per month for successfully completing Power Move monthly challenges. Note that customers may be eligible for Power Move without unlocking Beyond. In order to achieve full £1,617 saving, customers would have to purchase/subscribe to all currently available products and offers. Terms, exclusions and eligibility criteria apply. All offers are subject to availability and OVO reserves the right to replace or amend the range and value of available offers at any time.

As often happens, a second generation of new technology provides better results for the user and so, although installers and training still require some updating, we decided to make use of the offers currently in place and see what was involved for a Heat Pump installation. For qualifying properties and systems, there is a Government grant of £7,500 (BUS) and we went with a scheme which also allowed a ‘free’ survey (£200 payment which either is refunded or goes towards the final cost of install) and an opt out right up to the days before installation. Our survey was arranged in a few days and a surveyor arranged an appointment to measure and review the property. The survey suggested a heat loss just under 9kW and so the plans revolved around a 9kW heat pump installation. We currently use a condensing gas boiler for our heating and hot water and part of the survey looks at the pipework and radiators to check their suitability. Our outcome was that the pipework was ok but 6 out of 12 radiators would need upgrading - another benefit to our timing of the exploration was that the cost of the new radiators and installation would be covered in the overall quote. Positioning of the heat pump was the next consideration as there are regulations on noise levels and property borders. Planning considerations are also needed to be reviewed along with cabling for the electrical supply and positioning of the hot water cylinder. Further requirements might be materials in situ, especially with an older property and so possible additional surveys might be required. A property EPC (energy performance certificate) is also a requirement of the government grant. Many properties will already have this in place but as we have been resident for almost 20 years and no plans to move, ours didn’t have this in place. It is quick and easy to get this updated. Applying for the grant, planning permission (if required), additional surveys, other changes to existing pipework can be a fair bit to cope with but again, with our offer, much of this was organised by our supplier. One other trigger for us to look at swapping our heating system was that a review of recent years showed that approximately 96% of our property’s carbon emissions were the result of our gas usage. Ultimately we decided to go ahead, after researching other installs and so in a few weeks time, we will be having our system installed. Part 2 will look at the install itself.

Hi everyone, We’re excited to announce our new EV Charger Cover offer! Every journey starts with your EV charger – it powers the school run, road trips, and all your adventures. And now there’s a way to protect it. Our home EV charger insurance goes way beyond a standard warranty, from £3.50 a month. Plus, we’re offering eligible customers their first 12 months free if they’re signed up to OVO Beyond. Cover will include: Brand new charger replacements Fast responses within 24 hours, and 24/7 access to our specialists Vandalism and theft cover Full system insurance Eligibility: Eligible customers will: Have signed up to Charge Anytime or won’t be eligible for Charge Anytime, but have a charger Have purchased an EV Charger from OVO Have told us they have an EV in their Home Profile data How you can claim this offer: We'll reach out to you in the coming weeks if we know you already have an EV charger. You can also sign up via the 'Offers and Upgrades' section of your OVO app or online account. You can find out more here. Thanks, The OVO team

Updated on 20/01/25 by Abby_OVO Solar power is a great way to generate your own renewable energy, and gain energy independence. We’re proud that we’re now offering solar, even if you’re not an OVO customer. If you’ve recently begun your solar journey and had your panels installed by OVO we’d love to hear more about your experience. Not yet had solar installed but thinking about it? See our solar product page . Whether you’ve already got solar panels, are interested in getting them installed, or are simply a green tech enthusiast here to find out more – we’ve got a number of topics here on the Forum which may interest you. Find out more about OVO’s solar offering: Check out this collaborative user guide to all things solar: Here’s a community members guide to help if you’re planning a DIY-approach to installing solar panels: We're also looking to get some feedback from customers who have Charge Anytime and Solar, on what they would like to see if we were able to offer both services at the same time: Your advice and feedback might help other community members start their solar journey! 🙂 🌞

Updated on 23/01/25 by Abby_OVO Thanks to our partnership with Volvo Cars, you can get up to 2,700 miles of free driving* when you switch to OVO if you have an eligible Volvo electric vehicle. Just add our free Charge Anytime add-on to your energy tariff. You’ll also receive £50 in charging credit once you’re on supply. Volvo drivers with fully electric specific models will be able to unlock up to 2,700 free Charge Anytime miles. Charge Anytime allows you to smart charge your Volvo at a super-low rate of 7p per kWh** – anytime, day or night with no restrictions. Eligibility You'll need an eligible Volvo vehicle and a set-up that’s compatible with Charge Anytime. This offer is only available to new Charge Anytime customers. Please see the offer terms and Charge Anytime terms . Eligible Volvo EVs include: Volvo XC40 Recharge Pure Electric Volvo C40 Recharge Pure Electric Volvo EC40 Volvo EX40 For full details and to see if you are eligible, please visit our landing page or you can check your eligibility here by completing this form . *OVO is offering up to 2,700 free Charge Anytime miles through £50 credit for Volvo customers who add Charge Anytime to their plan. This offer is available to new and existing OVO customers who don't already have Charge Anytime. 2,700 free miles is based on a Volvo EC40 Single Motor Extended Range driving 3.8 miles per kWh, which equates to 714 free kWhs (actual sum: 2,714 miles based on WLTP). Our Charge Anytime rate is 7p per kWh when smart charging, which works out at £50 free credit. Actual mileage received will vary depending on your EV model, your driving style, and other external factors. We'll give you these free miles by adding £50 credit to your OVO account after you have successfully added Charge Anytime to your plan. View full offer terms and conditions here . *The 7p per kWh rate is effective whenever you smart charge your EV. If you'd like to override your smart charging schedule to top up quickly, you'll be charged at your standard home energy electricity rate. The next time you charge, you’ll automatically go back to your smart charging schedule.

This was supposed to be a short piece. My apologies in advance to the part of your life you won’t get back after you have read it but it does a condense a lot of thought and research into one article so I think it’s worth reading. To save time you can skip the boxes. This is an personal journal of how the use of energy in one household has evolved over the past few years with a surprising setback but also an unexpected development and future possibilities for getting towards Net Zero. However, this is not about how a typical migration might happen. This is about an experiment that was kick started out of the chaos that was the result of Covid and then Russia invading Ukraine and how it influenced my thinking about how to reduce my costs with very high energy prices.. What is being presented here is more of a journal of what happened over the past few years to our household and it’s about provoking thoughts and discussions on the various pathways by which Net Zero may be achieved and it can only be achieved if it’s affordable. Technical note: In physics, Lagrangian mechanics is a formulation of classical mechanics founded on the stationary-action principle (also known as the principle of least action – Ah, someone who understands how I run my life). In the same way, I believe the path to Net Zero has to be the path of least cost for the consumers of energy. If an option is not least cost then I don’t believe you will get the majority of people to take that path. In fact, they won’t be able to afford it. I believe that all the actions I’ve taken on my path were least cost, or at least speculation on the basis that calculations at least show they lead to a lower cost solution. Very little of this was planned. I didn’t have any clue as to where this was going to go before 2020. It just went down the path of least cost, and having seen a lower cost future, that is where this experiment is probably going to go. 2014 – August - Changed my energy supplier to Ovo – At the time the UK were running a significant number of coal fire power stations. Green Energy wasn’t such a thing as it is now. Certainly the thought of Green Energy wasn’t uppermost in my mind. I had retired the year before and instead of spending time earning money I was now spending time looking at ways of saving money. It’s what you do. My outgoings were somewhat more that my Railway Pension and I had to cut costs. I axed my BT Broadband and went to EE. I paid up the mortgage with my Endowment which had performed better than expected. Ovo was considerably cheaper than British Gas so I moved to a fixed plan and a SMETS1 Secure Smart meter was installed. 2020 – Time for an EV? – By this time the UK had decommissioned a lot of its coal fired power stations and wind power had really ramped up. There is a lot of noise now in the media about Climate Change. This had taken over from Global Warming as the dominant phrase. My 15 year old Ford Fiesta is now getting beyond its ‘Use By Date’ and I needed to change for something that was less expensive to maintain. Covid suddenly strikes and the world goes into a tailspin mainly of its own making as we would come to realise later on. Hindsight is a wonderful thing. World energy use goes down, or at least stops rising. No one knows the chaos that will ensue in the near future because of the disruption to energy production and the Ukrainians still firmly believe that the Russian’s threat to invade is just the usual sabre rattling. I’m looking at getting an EV and a number of spreadsheets later it’s obvious that the Zoe ZE40 is the one for us. Jenny is not so sure but generally trusts the decisions I make but to stop me making even more spreadsheets she agrees it’s probably a good idea. There is no getting away from the fact we need to replace the Fiesta. I don’t have enough money this year to buy a battery owned (as opposed to leased battery) ZE40 this year. Decision postponed. I buy a pair of ear defenders so I can’t hear the noises that the Fiesta is making. November. On the Ovo front I take out a two year fixed plan at 15p a unit. This seemed an average bet at the time. Little did I realise how good that deal was. 2021 – Definitely time for an EV - March – we briefly looked at having solar panels and were quoted about £4,000 for a full roof system. The result was that, without batteries, we could only use about 45% of the energy that we produced. We could sell with the SEG but that is only 5p a unit at best. As far as I was concerned that was practically giving it away. Batteries added another £2,000 but we were still only saving a few hundred pounds a year and most of that in the summer. I had considered solar panels and car charging but this is a technical nightmare and if you can charge your car for 7p a unit then there is not a lot of point in doing that. Solar really doesn’t have much going for it as far as I’m concerned. On the face of it it’s ‘free’ energy but the payback time – the only criteria that you need to apply to any capital expenditure – is about 10 years. No, EV it is, because I can’t afford both. July, we have enough money for a 2019 ZE40. There are three in England and one in Northern Ireland (not going that far and it’s half in the EU so heaven knows what complications could arise with bring that into England). One in Morecombe, one in Hartlepool and one in Plymouth. We look at the one in Plymouth, it’s a dream and we buy it. I don’t have a charge point so I’m paying roughly 30p a unit at my local car park. That almost seemed extortionate at the time. If only we knew what was going to happen. My EVSE (Electrical Vehicle Supply Equipment) Saga Time to get a Charge Point / EVSE and start the process. It’s going to cost £1,000 but I start it through Ovo. The first issue is that I want the EO Mini Pro which was originally on Ovo’s sign up page but has now disappeared. I call Ovo and they say I can go still with that. However, I’m looped. This means when my estate was built in 1980, to save money, the DNO ran a cable into my house and ran a loop from my house to my neighbour saving a bit of cable and not having to joint twice into the three phase feeder cable. To have a 7kW unit I going to have to get my neighbour unlooped from me. They’re an older couple and we get on well with them and we look after each other’s dog at times. Good neighbours. They don’t want their garden dug up though as they’ve just had it re -landscaped. Mmm. I was adamant I wasn’t going to get a 2kW slow charger. It takes a long time to charge and it has a host of issues including safety and lower efficiency. The final straw came when the DNO wouldn’t respond to me (and never did) regarding unlooping and registering a 7kW charger for capacity planning. I bought a 2kW Masterplug charging cable from Screwfix for £150. At least I’m on 15p a unit now. Actually 18.3p/unit when the 82% efficiency is taken into account. It would be 16.3p/unit with a 7kW unit. Later on it turns out that the EO Mini Pro was a unit that was prone to disconnecting itself from the broadband even with a good signal but to compensate it was very good at filling up with water. The company was hopeless at responding to customer complaints. Looks like I saved money and dodged a bullet. I opted to fix three of the 2kW unit’s issues. I added an Open PEN unit (fully disconnects the car on losing the three-phase earth back to the sub-station), replaced the three pin plug with a Commando plug (overheat issue) and socket and bypassed the small internal contactors (long term reliability issue) with an external contactor rated at 20A (for a 9.5A charging current). The last issue, 82% efficiency because the Zoe takes about 300W standby power can be fixed by upping the charge rate to 3.5kW. It would then be about 87%. 3.5kW because that is the limit that the DNO will allow you to go without having to inform them and it’s a safe level if you are looped with a neighbour. Side Note: The engineering of enclosures I have a lot of experience of keeping water out of enclosures. A lot of start-ups (and there really are a lot of those without enough engineering experience) seem to think that all you need to keep water out of a unit is make it IP65 or better. Wrong! Making it IP65 stops gross water ingress but doesn’t stop the unit breathing in moist air when the atmospheric pressure changes and then condensing out on the inside when the temperature drops. The water tightness of the unit then stops the water getting out. Consequently it slowly and steadily fills with water to the surprise of everyone except people like me. You at least have to have a drain hole, which then doesn’t qualify it for the IP65 rating. But it’s the IP65 rating that sells units because people don’t know any better. I make my own units. They are fan ventilated at a very low rate. No filling up with water. No overheating in direct sunlight. When I researched getting an EV I spent 90% looking at cars and 10% on charging it. With hindsight, it should have been the other way around. The cars are just cars but finding a decent EVSE is not easy. Good luck! September – We’ve only had the car six weeks and there is a perceived future shortage of fuel (by the press) caused by a supposed shortage of delivery drivers. Panic buying fulfils the prophecy by creating a real shortage of fuel. We breeze past filling stations with massive queues. Those that had no queues had no fuel either. Time to feel smug about having made a timely call. In reality it’s just good fortune. Side note: The car we would have bought instead of an EV If we hadn’t bought the Zoe it’s very likely we would have replaced the Fiesta with a petrol Skoda Fabia with a fuel consumption of about 11 miles/litre so all comparisons are now compared to that. With the 2kW charger I’m now saving an average of £75 a month on fuel costs. On top of this for petrol/diesel at least 50% is tax. 70% of what you just paid tax on you throw away as heat. Some of that can be used in winter otherwise it’s a complete loss. The EV is eerily silent (points on the licence for inadvertent speeding is now a real possibility but thank goodness for speed limiters), it’s the smoothest automatic you have ever driven. I call it my magic carpet. We were going to keep the Fiesta for long journeys. A two car PHEV solution if you like. Jenny said she was going to use it for that, not having the confidence to trust an EV to do a long journey. The lack of confidence didn’t last long. She never drove the Fiesta again. It sat outside unused and unloved so we sold it to a mechanic friend who could do the expensive cam belt change that it needed. We have gone full BEV. No safety net. 2022 – Winter came and we use the defrost feature to condition the car before driving. No more scraping ice and sitting in a freezing car that is reluctant to start. At the press of a button on the key fob the car becomes warmer than the house in 10 minutes. Russia invaded Ukraine. Everybody was shocked but we kept calm and carried on except the rest of the world which went into Tailspin 2 and started grabbing LNG Gas Tankers like a Hungry Hippo game on steroids. We had more money so we won that game at a considerable cost. July – Fuel shortages start. Gas prices reach astronomic levels and everybody is now in real shock due to the double whammy of Ukraine being invaded and the post Covid recovery soaking up a reduced gas supply. Petrol is £1.92 a litre. I’m still on my 15p tariff (sounds of hands being gleefully rubbed together) and now £140 a month better off (summer BEV efficiency (4.8 miles / kWh – do the maths) vs petrol price). Energy suppliers go bust, EV prices skyrocket. We can’t believe our good fortune. Everyone else is suffering badly but we aren’t because of a simple, earlier decision. The impending huge increase in tariffs galvanises me into topping up the loft insulation to 300mm and the cost is a no brainer. We also have cavity wall insulation from 2006. November. Our two year fixed deal ended. EBSS came and went. 2023 - May my tariff is 34p and I’m still saving but it’s down to less than £40 a month. Not looking so good now. September - falling tariffs and summer BEV efficiency means I’m back up to saving £80 a month. To be honest, driving an EV is such a great experience all round that I’m not overly bothered on the reduction in saving but more is better. Electricity is also a lot greener now and only occasionally give in to the temptation of giving petrol stations the bird (especially tempting when they put their prices up on a Bank Holiday) as I glide almost silently past. On an Ovo web page I saw there was an add on called Power Move. You could save £10 for September if you kept your usage during the peak to less than 12.5%. I joined a few days into the month and very easily picked up £9.52 for essentially doing nothing. Sometimes I had been charging partly in the peak but now this was all moved to 10pm and later. I then succeeded in all the PMs from October to February. I decided to see if I could help out on the forum giving tricks and tips to those who would listen. During this time I was reading up on power generation and a lot of the good blogs came from Octopus and Squeaky that were just groaning with information and this explained how the market for trading power occurs at different times. Futures market, Day Ahead and the Balancing Mechanism. This led me to pay more attention to Agile Octopus, the Day Ahead market and pricing. Neither my car nor my charging set up was compatible with Ovo Charge Anytime so I had no way forward there. I looked at other utilities but these either had similar equipment limitations or had restricted hours. There is no good solution to be had apart from taking a risk with one particular product. November – Ovo have a good rate for Heat Pumps so I’m now looking to go with one of those to be greener and save a bit of money. I’m not expecting to save much if any. Back in 1999 British Gas put in a new boiler for me. The original one, from when the house was built in 1980, had lasted 19 years and, incredibly, our Potterton 60e (gravity fed) boiler is 24 years old now. It’s 75% efficient so not too bad and I run it at the lowest possible temperature. It’s now old enough for it to move out. Granted, it was well maintained and we have always had a wood burner stove which takes a lot of the winter heavy lifting. This left the gas boiler to top up and even out the temperatures around the house with TRVs on the radiators. We paid for a special offer Ovo EPC survey for £25 and £350 for a heat pump survey with Heat Geeks who had a lot of good blogs on heat pumps. I also did a heat loss survey (it’s just physics) and had very similar results to HG. It showed a deficiency in the extension on the front of the house where the extra radiator was too small for the heat losses. All the other radiators were fine and we never had a problem with heating the house except for the extension and the bedroom above it even on very cold days. The TRVs were good for keeping the temperature lower in the rooms we didn’t use so much. I was expecting something like £11-12k and this was the guide figure for our size / type / age / insulation level of house. You can imagine that we were a bit stunned when the quote came back at £16.5k. In the quote all the radiators had to be replaced. The very same radiators that the old gas boiler was very happy to heat with a 50C flow temperature and no wood burner. This is a 43 year old house (only four years above the average) with 22mm pipes (newer properties have micro bore) , cavity wall and 300mm loft insulation. We would also have to be unlooped (Nooooo, not again!) from our neighbours as before. You also can’t zone the house with TRVs as it reduces the efficiency of the heat pump. That is a complicated story and best left to the Heat Geek blog to explain but essentially a heat pump driving a conventional central heating system is only just able to reach it’s COP target. If you change the flow rate with TRVs (you zone the house) you reduce the COP so much that keeping one room slightly cooler means that it becomes even more expensive to heat the house. We declined and I was at somewhat of a loss to know how to make the house greener but we weren’t going to do it at any cost. 2024 – January. For the past few months I’ve been looking at Cornwall Insight to look at energy prices in the long term. I came across one or two articles elsewhere saying that rates are not likely to be dropping significantly in the next decade as the latest round of strike prices for power generation had been at a much higher level than previous due to the significant bout of high inflation that we just had. In fact, with the strike price limit imposed by the NG ESO in the first round not all the generation capacity was fulfilled. No one wants to build infrastructure at the old rates. On the Speak EV forum I had been tracking comments about different tariffs (possibly the top issue for discussion these days) and Octopus, and specifically Agile Octopus had come up quite a number of times. I found it was possible to download Agile data as far back 2018. Using my Ovo usage data I could run that against the HH Agile rates (do a HH convolution) and work out whether I would be better off or not. The results are In 2018/19 is not representative of today’s level of green energy production. 2020/21 was atypical due to Covid. 2022 was horrendous in terms of pricing and I would have just broken even but peak rates were up to 75p a unit (£350/MWH wholesale, For comparison the Hinkley C strike price was considered expensive at £92/MWH in 2012 ) 2023 showed a marked decline in rates and less spiking and I would have saved about £200 over the year for the car but a slight loss for the house. 2024, however, showed the same downward trend and predicted of a saving of £350 for the car and £150 for the house. I wasn’t expecting to save on house use. This is also with us not changing anything in the way we use power. Going back to Power Move, I figured if I could do that with the ease (usually managed 7-8%) then moving to Agile Octopus was the logical next step. I really want to stay with Ovo. I had been with them for 10 years and not had any regrets but I had no way to move forward with them so, reluctantly, I click the button to switch to Agile Octopus. March - Octopus took over my meter readings and although it was a SMETS1 meter they did the transfer in the 14 days they said they would. Since then a couple of things have happened. Firstly, the rates have continued to come down from the January/February levels. In fact, the All-Day average price is running very close to 50% of what it was doing 12 months previously and that was on a decreasing slope from the highs in 2022. This means my early predictions are underestimates and I could end up saving as much as £600 on a £1,200 electricity bill. The gas is a similar rate to the SVT anywhere so no savings there. Well, that turned out to be wrong but for a totally unforeseen reason. The big (but smaller) light bulb moment 1 The day ahead price is subject to very big dips on occasions when the unit price goes to near zero or even negative and it like trying to imaging negative bank rates. Surely, if the bank rate were to go negative you would take out the biggest possible loan that the bank would give you and rake in the money. It doesn’t take an Einstein to realise that when prices are that low (or even negative) you can plug in an ordinary fan heater and heat the house that way. And for nothing. Thank you B&Q for selling me a 2kW fan heater for £7. That paid back very quickly. I then pondered at what unit price it’s cheaper to heat with a fan heater than the gas central heating. It turns out the formula is obvious and simple. It’s the gas unit price (then 7.15p) divided by the boiler efficiency (75%). In my case it was 7.15 / 75% = 9.53p. Well, I’ll have as much of that that you are offering thank you very much. Some nights the rates have been zero and the house is really toasty warm in the morning. The fan heater goes on, the central heating goes off and it has cost me …. nothing and saved on my gas bill and it’s greener because the wind is pushing all those big fans around. Hang on! Agile was about saving money on my electric bill but I’m now saving money on my gas bill as well. The problem is it doesn’t happen that often but it’s better than a poke in the eye with a sharp stick. The big (but smaller) light bulb moment 2 Moving on. Same as above but with near zero prices why not switch on the hot water tank immersion heater when prices are low. I don’t have one at the moment but I’ve ordered one to go in my new tank for my new boiler. Same equation applies but because this will only apply to the current tariff (6.18p) and new boiler efficiency (90%) it comes out as 6.13 / 90% = 6.8p. Now there aren’t many opportunities to do this but when you do have long periods of qualifying prices but you can heat the tank to 80C (instead of 60C) and use it as a heat battery and save gas sometime after the Agile prices have risen again. You can opt for a higher price threshold to save more gas but the costs rise very steeply. For the immersion heater and the fan heater to save money work you have to use these intelligently and they relate to the gas margin price as I call it. The small (but huge) light bulb moment. BUT. Why are you using a fan heater when you could be using a heat pump which is at least three times more efficient? Whoa there, you’ve got a short memory there buddy. We rejected the heat pump remember. BUT. We don’t need a hugely expensive 7.5kW heat pump plumbed into a central heating system it can barely run. We can use a £800 air-air conditioning unit that also works as a heater. An air-air heat pump (AAHP). Ok. If the heat pump is three times more efficient (0.815 kW in / 2.93 kW out so a COP of 3.6) what is the revised formula to calculate the break-even price for gas? Gas price (6.13p) divided by the gas boiler efficiency (90%) times the COP (3.6) for an AAHP. It’s now 6.13 / 90% x 3.6 = 24.5p. <Please insert your own phrase of sudden surprise here>. Now, of course this is not going to work with an SVT but the vast majority of Agile prices from midnight to 4pm (every single day) are below 20p. We can now have electric heating at any time from midnight to 4pm. Apart from the coldest days this will replace a lot of the gas heating during this time. After 4pm it goes back to gas. As a bonus (as if we needed one at this point) it’s not only cheaper but greener. Instead of 100% gas we are now using 75% green energy. I’ve estimated that it would save about 4-6,000kWh of gas during the winter heating season. There aren’t many HH events that are priced at 10p or lower so the saving is relatively small up to this point. From 10-15p there is a very large number of events and you sort of reach the minimum around 20-25p. After that there is a slow rise but only because there are only a very small number of events above 20p. This result means you don’t even have to do intelligent, price related heating if you restrict the operating period to 0-16:00pm. Of course, if the price should spike for some reason you can turn the air con off and use gas heating. The above graph shows the gas use before (red) and after (blue) the air-air heat pump is added. The smaller blue plot is the gas usage after the 4pm cut off for the pump and before it comes back on at midnight. This is the average Agile rate for the first three months of 2023. You could tailor the timing to miss out the rise between 6am and 9am and this will reduce the loss due to higher rates but it will also cut out some of the opportunities to cut out gas use. You can therefore make a decision to either optimise for cost or optimise for reducing gas usage (or somewhere in between). Money or Green, you decide. As we are saving big time on charging the car and house usage this could be optimised for gas reduction and utilise the whole of the 0-16:00 period. You could also include from 10pm onwards. Gas heating will therefore happen between 4pm and midnight. There is no electricity usage for the AAHP between 4pm and midnight and particularly not during the peak. In our house we also have a wood burner so this takes over from 5pm to 11pm and generally keeps the gas central heating off during these times anyway. We still need the gas boiler for the majority of water heating. But in case you want more efficient water heating In looking for a heat pump version of a tank water heater I really wasn’t expecting to find one but you can actually get these. I think these are more popular in the USA. They cost about £1,400 but with the reduction in gas associated with heat the water (only about £150 gas usage over a year) there isn’t really a sufficient saving to make a business case for it. And it will be difficult to integrate this with a gas boiler. Well, I tried but not every idea works but, actually, there is still a more radical option at the end. Who said we still need a gas boiler? Where we are now So here we are, most of the way through April. We had another session of zero prices. My effective average tariff for the car is now 8p a unit but that could go up again. The average tariff for the house is 10p. If I had been on Ovo this would have been 27p earlier in the year and 24p now. The usage split between car and house is roughly 66% to 34%. The savings split is roughly 72% to 28%. Because the average Agile price has continued to decrease the projection for the year could as much as £700 for the car and house but could end up at £600. There was no cost to making this saving other than changing my supplier. Invest to do better If I fit the AAHP that should save (from the graph) another £200 a year. The immersion heater will save £20/30 a year but possibly more if we use it as a heat battery on occasions. The AAHP and immersion heater will save a lot of gas which makes us a lot greener. We could be down to as low at 20% of the gas typically used in a four bedroom, detached house with the occupants at home all day. What are the lessons from this? My son is an aircraft fitter. He repairs and modifies aircraft. He is a very skilled and experienced person. His favourite saying is ‘Don’t force it use a bigger hammer’ (as a joke). The big hammer we have at the moment is the gas boiler. The government would like to change it for another big hammer called a heat pump. The trouble with big hammers is that they are not subtle tools and apart from a few jobs they are not suited to many roles. The obvious trouble with gas boilers is they use gas. The hidden problem with heat pumps is they are generally unsuited to running a central heating system in the average house. Heat pumps have no problem with running air to air because air has a very low viscosity and flow rate is paramount in heat exchangers. For a heat pump to run a central heating system you would ideally have 28mm pipes everywhere and double panel radiators. This is fine if you set out to build a house this way but otherwise it’s a bit of a compromise and retro fitting a heat pump into the average house can be expensive and it’s not going to pay back in its lifetime even with a grant. Later on you won’t get grants. If it’s going to be expensive people are not going to have them fitted. In contrast, AAHP are small, cheap can be DIY fitted and still have a COP of over three. You could have a number of these distributed around the house so long as you have an outside wall. You just need the right tariff to run them. This has been an incredibly interesting exercise reimagining what you could do if your electricity costs were significantly lower than the SVT/Fixed Price and the biggest surprise was realising that lower electricity prices coupled with an AAHP fitted in the lounge will significantly reduce gas usage and make the house greener. … to be continued in Part Two!

...Continued The diagram is a crude illustration of how the various technologies compare in installation and running costs. The heat pump starts off at a minimum of £500 per year due to the initial cost and that is after the grant. It’s over a £1,000 a year without a grant. The AAHP is standalone, £800 over 10 years. The gas boiler starts off at £4,000 over 15 years but probably 20 as it’s very lightly loaded. It’s only really going to be used on the coldest of days or if the electricity prices are high for some reason. With TRVs (that you can’t use with a heat pump) the gas boiler will only be heating the other rooms in the house as required to balance the heating. You are only asking the AAHP and the gas boiler to do what they do best so the combination is saving both money and gas at the same time. The immersion heater is saving gas on the lowest priced days but it’s capable of storing a certain amount of extra heat (as a battery) for later use so may save more than is initially estimated. Some final ramblings Two or three AAHP distributed around the house is roughly the maximum heat load for the house. Total cost about £2,400. Each one is only 800W so it will easily come off the ring final circuits (used to be called ring mains). No major re plumbing. I’m now beginning to wonder why we need to have a central heating system at all and what would be needed to get through the 4-7pm peak. There is still is the need for water heating but there are solutions for that as well. If you are not paying for a gas boiler then there is the heat pump water heater instead. That is too far for where I’m going but the AAHP has been ordered. Jumping ship I changed my energy supplier because Ovo wasn’t offering a tariff that meant I could reduce the cost of charging the car but it has turned into far, far more than that. Yes, being on the wholesale day-ahead market isn’t going to be what most people would want to do. There is also a lot of active management of usage for the car and immersion heater at the moment but I have now joined a group at Octopus to explore the use of IoT technology that can read Agile prices and they can switch on and off when compared to a threshold and other criteria. For the immersion heater the controller would have ‘when agile < gas price / boiler efficiency’. For the AAHP, it would be on a time switch and work perfectly well but its controller would have ‘when agile < gas price x COP / boiler efficiency’ control. COP and boiler efficiency are both constants so that effectively just translates to ‘when agile < 24.5 then Switch On else Off’. To be more green you can set the threshold higher but it’s probably still best to keep electrical equipment off during the peak. The car is more difficult and the ‘when’ condition is a lot more complicated and is related to ‘price’, ‘battery level’ and ‘future use’ and it may not be possible to automate that satisfactorily. The combination of Future use / Battery Level would have to override price and some benefit could be obtained from not only knowing the price tomorrow morning but the price for the day after that in that delaying charging could take advantage of lower future prices. On the other hand it may not result in a significant decrease in cost. Side note: Heat Pumps and all that new-fangled nonsense - What is the issue with heat pump used with central heating systems? There is nothing fundamentally wrong with heat pumps. In fact it’s the only way we can go to improve energy efficiency and have a greener future. The issue is the way that it’s being done. The AAHPs work very well. They have been around for a long time and they have a COP of around 3-4 and higher for most of the temperature ranges you are going to see. They work well for two reasons. They only have two heat exchangers. The outside air to cold refrigerant and then the hot refrigerant to the inside air. They work with air as a medium which has a low viscosity and the heat exchange is assisted by fans and the air channels are wide and very short. In contrast, central heating heat pump systems have three heat exchangers. The first one is the same as above. The next one is hot refrigerant to water. Water has a high specific heat which is very useful but has a much higher viscosity and pumping losses than air and it’s very difficult to push it through the all the thin, bendy pipework that constitutes an average house central heating system. In fact, this is such an issue that although the water loop goes outside to the heat pump you can’t add antifreeze (normally glycol) to it as it further increases the viscosity to the point where it won’t work effectively. The Heat Geek surveyor had charts with him to show that. The third and worst heat exchangers are the room radiators. These typically don’t have a fan so the heat transfer rate is very poor and it ultimately reduces the COP of the heat pump unless you effectively double the surface area of the radiators. The weakness of a heat pump coupled to a conventional central heating system is therefore the viscosity of water in long, thin pipes and the poor performance of room radiators. You can overcome the last issue by changing to underfloor heating with floor insulation. That increases the surface area, decreases the water temperature necessary and decreases the resistance to the water due to parallel paths. Retrofitting the average house is very expensive and uneconomic and not possible with all houses. New houses should be built with insulated floors and underfloor heating. As far as I can see it’s seen as a desirable feature for new build houses but not a mandatory requirement even at this late stage. The surprising physics of heat engines In physics the COP (coefficient of performance) is a part of Carnot’s Theorem on heat engines and there is a theoretical upper limit to the COP for a heat pump given the input and output temperatures. From the graph below for an input temperature of 0C and an output of 40C (slightly lower than that required for a central heating system) the upper limit is about 8. This means spending £16.5k to get a COP of only 3 or 3.5 from a central heating heat pump is rubbish. It tells us there are limitations in the heat exchanger (HE) design (they need to be bigger) particularly the last HE, the radiator, which is particularly poor. Changing to underfloor heating increases the surface area and reduces the water temperature but water flow rates are still an issue. In contrast an AAHP has an input of 0C and an output of about 20C which means its COP could be as high as 15. This means that if you were to be able to realise this value you could heat a 4 bedroom, detached house with average insulation using a maximum of only 500W of electrical power. This is obviously nonsense because the relatively small size of AAHP means there are compromises on the two heat exchangers that reduce this value and also the type of refrigerant used but it has the potential to be much higher that a heat pump feeding a conventional central heating system. The ethics of negative prices (inset picture; My 6th April electricity usage: 23kWh of electricity; Cost = -£0.19) On Speak EV this point came up in a discussion about Agile prices when they went negative (again). If Agile are paying you to use electricity then anything you can do to use electricity will result in an actual income. I’ve had one or two days where my usage was concentrated on half hour periods where the price was strongly negative and my net cost for the day was negative. Not a huge amount but on one day I actually got paid to charge the car, heat the house and do loads of higher temperature washing. If you are using a fan heater then you may get to the point where it’s so hot in the house you need to put it out in the garden and heat that up instead. You could say that this is unethical and it’s a moot point but you have to understand where negative prices came from in the first place. Side Note: Day Ahead prices and when it goes negative This is my understanding (in the simplest possible terms and with probable omissions and errors) on what happens and it starts with the law that says that the National Grid (and the through the utilities) has to meet the peak demand of all its customers all the of time. To do that the NG has to arrange sufficient generating capacity, though long term contracts agreed at a strike price. This is the Contract for Difference (CfD) mechanism. This means that whatever price the electricity actually gets sold at, at the moment of generation, the generator will get that price. If it’s sold for less than the strike price then the LCCC (Low Carbon Contracts Company) will make up the difference and if sold for more, then the LCCC are paid the difference. The LCCC was created to allow for renewables generation to enter the generating market because their output can’t be defined in advance. The utilities have to ensure they have enough energy to pass on to their customers to meet the full demand. To ensure they can meet the contracts (Fixed Price and SVT) with their customers they overbuy their energy needs on the futures market some time in advance based on expected number of customers, expected load, expected weather conditions etc. However, none of those guesses are going to be right on the day so they hedge their energy demands. The Day Ahead Market: About 36 hours before the actual moment of generation (and near instantaneous consumption) the NG now has a good idea on demand and generating capacity on line at the time of generation. It’s at this point where the utilities (or at least their computers) note that they have overbought based on tomorrow’s actual conditions that are actually not average. The demand is lower, it’s warmer and the generators have sunnier or windier conditions than the average. They then push their unwanted demand back onto the market which according to the supply/price curve pushes the prices down. The demand/price curve is opposite; if the price goes down the demand goes up. So, the NG is stuck with the supply that was bought on the futures market by the utilities and it can’t do anything with that but allow it to be generated. What it can do is push the price down the see if it can drive the demand up to match the supply. There will always be extra offtakers if you push the price down. Me for one! The generators will willingly offer lower and lower prices to stay in the ‘generation game’ because their strike price will be met by a top up from the LCCC. This is until prices reach zero. The generators cannot go negative as this would create a ‘negative market’ which doesn’t have a bottom limit. They would also forfeit the CfD condition in being compensated by the LCCC if they do. However, if there is still too much generation capacity then the NG can create a negative market and the generators still get the LCCC top up. The lowest negative price in 2023 was -19p which equates to a generator paying out about £90 for each MWH generated but still being fully compensated back to their strike price. In the worst case the NG could pay a curtailment charge to the generators to scale back generation but this is very costly and it’s generally cheaper to stimulate higher demand with negative prices. So, the LCCC could be out of pocket big time. They are a government owned company but they don’t have a budget as such. Their costs are not paid by taxes. Any loss that the LCCC makes (including running costs) is paid for by the electricity supplier obligation levy on the utilities. This is then paid for by the users as part of the SVT and Fixed Price contract price. For Agile pricing the price paid per unit is 2.1 x Wholesale Cost. After paying the Wholesale Price the remaining 1.1 is the profit element for Octopus plus the LCCC levy and their running costs. The last part of the market occurs at the time of generation and is called the Balancing Mechanism where an NG computer issues sharp changes in the unit price to encourage or discourage power generation (possibly even very agile demand) to keep the frequency within limits. Adjustments are made to the generators via the CfD contracts. Meanwhile, The Only Way Is Ethics So, negative prices and people putting heaters out in their garden is perhaps more of an issue about shoehorning renewables into a CfD mechanism that it wasn’t designed to accommodate and less about the rights and wrongs of wasting electricity. Because of the law the cheapest option that the NG has to meet its contractual obligations with the generators is to set negative prices on occasions and quite low prices a lot of the time. The average, long term, all-day price for Agile is 15p. And finally, the strange world where HMRC pay you to use electricity I’m not even sure if this is true but it follows on from the maths. If you consume electricity and pay for it then you pay VAT at 5%. However, if electricity is negatively priced then the VAT is also negative. I.e. HMRC is paying you to consume electricity. Now, it’s only likely to be only be a penny or two at most in a day but the sheer madness of that is out of all proportion to the financial reward and how strange is that!