Air Source Heat Pumps (ASHP) - How have your energy usage and costs changed since getting one installed?

I don’t mind the thread being public. I guess a lot of people will be put off buying a heat pump when they read that their bills are likely to go up. I don’t want to put people off buying a heat pump because they are great (just look at the energy usage and think of the carbon savings!), it’s just that gas is cheaper than it should be, and electricity is more expensive than it should be (there should be a heat pump tariff). Maybe it’s better that people have realistic expectations, I guess.

Completely agree, @briannolan. 

I’ve moved this topic thread into the public ‘Smart Home’ category now. No change other then that, I’m keen to hear from other heat pump members when they come across this topic. 

I know for a fact, @juliamc has some very good looking charts from the data she’s been collecting since her heat pumps were fitted…. which thread did you post those in, Julia? 

No idea @Tim_OVO !!!  but here are three more graphs for you 

This is March - Dec 2020 - showing our normal pattern of use before the heat pump, I just accepted the fact that we used loads of gas autumn winter and spring. We had a gas powered warm air heating system, and the hot water was heated just with an immersion. Summer gas use was (unbelievably ) mostly the pilot light on the gas unit, plus the hob. Spikes in the electricity are EV charging.

Then the heat pump was fitted and started working in March 2021. Sorry, graph colours reversed: gas now shown in blue !! The EV data has been removed for this graph.

I look at this with a warm feeling because of all that gas I’m NOT using now. I still have the warm air unit (the pilot light’s off now) and I hope not to use it again. If possible I’d like to repurpose it as a ventilation system one day. Whether the heat pump is enough in the depths of winter is still to be proved of course. It really shows how inefficient the old heating system was. 

Btw: to get the data for these graphs I laboriously copied kWh and price from MyOVO !!

In this graph I’ve shown just the heating costs ie. gas data while the old system was running, then the electricity used for just the space heating function of the heat pump, showing the comparable costs:

The last few days show when I set the ‘Holiday’ mode on the heat pump. Seemed like a good idea as we were on holiday… However, I could see (remotely using the phone app) that the house temperature continued to drop, so I switched it back on after two days. I think it used more electricity warming the house back up than I saved by letting it cool down. Won’t do that again unless it’s summertime !!

Bad electricity day yesterday, with the cold weather. 60kWh, although we did charge the car (it's a phev so takes a max of 7.5kWh).

I don't have daily figures for our gas usage in previous years so I can't see how much gas we used on cold days, which would be a useful comparison.

It isn't so cold today so I'm hoping we're back to a less scary level.

A rough comparison of my energy costs for heating from May to present:

Previous total gas cost for these months in 2020 was around £215 (included a little use on a single burner hob and also the standing charge).

2021 heat pump use since installation in May is £158 for central heating and £32 for hot water (£190 total) including the cold weekend we’ve just had which I think must have added around £20!

This is based on a unit price for gas of 2.77p and day/night electricity of 16.3p/5p. If you run the same calculation with a gas price of 4p and day/night electricity of 24.8p/5p you’d get a cost of £400 for gas v £275 for electricity.

So the numbers are looking ok for me, although without a cheap rate overnight the savings compared to gas would be less.

Do you have any expectations about what the comparison might be over 12 months including the upcoming winter, @nealmurphy ? 

Can I ask how you are finding the i life 2 radiators vs standard radiators in general, @M.isterW ? 

It's difficult to compare radiators as they were fitted at the same time as the heat pump but they work okay. In mild weather the house heats fairly quickly but yesterday when it was very cold it took a long time to go from 18 to 20 in the afternoon/evening. I did see that another person with the same setup had a bad heat day yesterday so I wonder if the systems aren't coping well when it's very cold.

 I do have a few minor annoyances with the rads.

1 - They can't be zoned so we heat the whole house or none of the house. For rads that cost nearly £500 each that's fairly poor.

2 - They thermostats seem to be at the bottom so don't always read the room temperature very well, particularly if you have furniture in front of them.

3 - There are only two sizes. Our smaller rooms have radiators that are too big (not really a problem) and I think our sitting room needs a bigger one. After the trial is over I'm going to ask SGS about fitting a second rad in the sitting room, next to the existing one.

My energy usage with a heat pump not working 100% (maybe that’s helped…)

2020: 3900kwh elec, 13520kwh gas. £1188

2021 estimate: 8500kwh elec. £1106 on previous tariff, so very close to gas equivalent running costs. Unfortunately my company went bust so on new tariff it will actually be closer to £1800. 

OVO - let’s have a heat pump trialists tariff please🙏 😁.

That’s a +1 from me for the heat pump tariff please, or even better lobby the government to drop the 26% renewables electric tax on heat pumps! That would certainly help.

@Jess_OVO @Tim_OVO Seriously though, I am wondering if we can help design a tariff that takes account of the need for a morning warm up time and hot water heat-up, say starting 5am (so as not to wake everyone up too early)  and ending at 7am, maybe 8am (not sure this would be too late to tie with cheap rates). You guys have our data so will know how much energy is needed when to get us up to temperature. 

@Transparent any thoughts?