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Best answer by Peter E

​@andykelp 

I thought I would come back on here and update you with what has happened with our first heating season with an A2AHP.


It was a learning curve but worked very well, produced  4642 kWh of heat for an electrical input of 1269 kWh giving a SCOP (Seasonal COP) of 3.66 which is slightly better than what the manufacturers said it would do and that figure is for an average of 5C outside temperature and inside of 20C.


As far as noise is concerned, as it's in the hallway, running a full power on the coldest days its no problem. It has a quiet mode for night-time running and that was slightly more noticeable than we would have liked so I fitted a ‘hush kit’ which I made from plain, white melamine shelves, 100 cm x 30 cm. It only took a few brackets to hold it together and some plastic angle to cover the sawn edges. As you can see it then became a cabinet that my wife populated with various ornaments and plants whereas before it wasn’t something you could do anything with. The cost was about £80 for the bits compared with £700 for the heat pump, an IQOOL-SMART15HP.

 

 

The top part is a duct that takes air from the left hand side and into the top of the unit where most of the noise was coming from. In the cavity, which has a tilting lid, I put ventilation duct sound proofing material to cut the noise exiting to the left. That was very effective.

 

 

We also got used to the sounds that it makes over a period of time so we met somewhere in the middle.

 

 

The heat pump was only one of four sources of heat. The others were Solar Gain 7%, Wood burning stove 23%, Fan heater 3%, and a very much reduced amount of gas from 70% down to 18%. We saved about 7,000 kWh of gas and, without setting out to do so, also saved about £140 on the combined gas and electricity bills.

 

We’ve always have a wood burning stove but we used a lot less this year as I now only use it to cover the 4-7pm peak where my Agile Octopus rates are the most expensive and the heat pump is off. At practically all other times the heat pump is cheaper to run than gas. The lounge has large windows and the room has a significant solar gain on those sunny but very cold days.

 

The use of 3% for fan heaters stems from the Agile Octopus rates which go to near zero or even negative when it is very windy in the winter. Effectively we have the wind turbines powering the fan heater which is logically quite a neat solution. They were a bit of an experiment this year, a lot quieter and more powerful than the heat pump on full power so I used them to overheat the lounge overnight which then acts as a short-term heat battery for the morning and the heat pump runs at a much reduced rate until about midday. Sometimes it would cost me nothing for about 20kWh of overnight heat and I can charge the car as well (another 12 kWh).

 

The remaining gas was used to help the heat pump on the coldest days which has a maximum output of about 4kW. The HP can work mainly on its own to an average outside temperature of about 10C. Below that we need additional sources of heat particularly during the 4-7pm peak when it’s off.

 

I hope the information is useful. For me the last heating season was very instructive and the A2AHP is definitely here to stay. My wife likes a cabinet in that location.

 

Peter

 

18 replies

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juliamc
Rank 20
juliamc
Rank 20
September 9, 2024

Thanks for all this info @Peter E. I’ve been trying to persuade a friend of mine that if they buy a flat with old storage heaters they don’t need to replace them with a gas boiler, they could get something like this. I see you have an immersion though, did you consider an instant hot water gadget and electric shower ? 

    Peter E
    Super User
    Peter ESuper User
    Super User
    September 9, 2024

    @juliamc I've kept my gas boiler, in fact, I've just replaced it as the old one was 24 years old. The A2AHP will be working in conjunction with the gas boiler which is a very common combination in the USA. The heat pump takes most of the load most of the time but the gas boiler cuts in on the coldest days balancing the heat around the house as all the radiators have TRVs. This way I am hoping to reduce 90% of my gas use under the Net Zero protocol.

     

    There is a common misconception that Net Zero means you have to zero your fossil fuel usage. Not true. You just have to reduce it to a point where it can be offset with something like carbon capture. Gas is an incredibly useful source of energy when it very difficult or very expensive to use electricity like an HP trying to work at very low temperatures. You can only use gas to generate enough electricity when you have the cold, dark, windless days in the winter. You save the gas for the most difficult sitations. With the electricity tariff that I have I can cut about 7,000 kWh of gas and also save about £200 a year (cheap electricity used by a heat pump) in total between gas and electricity.

     

    I have an immersion heater that has displaced all the gas I used to use for hot water heating. However, it isn't economic on a Fixed Term or Standard Variable Tariff so I now have a ‘wholesale related’ tariff and use a timer to select the cheapest half hour periods during the night/day. It actually breaks even with gas given that the gas boiler is only 55% efficient when heating hot water. Shocking but true even with a brand new boiler. The 90% efficiency only relates to central heating use. We have an electric shower.

     

    And lastly. I only spend a £100 a year on heating hot water. I might save £50 a year at most with locallised hot water heating and that is nowhere near enough to buy three water heating points and rewire the house. I currently have the cheapest solution but it is still under trial.

     

    I hope there are some useful ideas and thoughts in there.

     

    Peter

    Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
      juliamc
      Rank 20
      juliamc
      Rank 20
      September 9, 2024

      Thanks again @Peter E  !! All good !! And on those cold foggy windless days our electricity will have to be generated from gas too, so in that respect you’re cutting out the middle man. 

        Peter E
        Super User
        Peter ESuper User
        Super User
        September 10, 2024

        One final and quite important point is user perception. My wife, Jenny, was quite sceptical of all these things I was introducing but is very tolerant of me experimenting. Wasn't sure about the EV but wouldn't drive anything else now. Wasn't sure about the A2AHP especially with me drilling two, seven inch holes in the wall. However, it has a heater mode that makes it very easy to finish drying off washing now that it begun to rain. Has a fan only mode for the same purpose. It has a dehumidifier mode for the same reason. Has a cooling mode for when it is 30C outside and we can sit in a pool of cool air at 22C.

         

        Important notes: The hot air circulates itself upstairs which is what we want. Cooled air sits in a pool downstairs where we want it. The bedroom has an Eglo ceiling fan which is perfect for getting to sleep at night. We've found cooling a bedroom is not ideal. Someone is too hot or too cold. You just need circulating air and it’s a very low cost option.

         

        The immersion heater was neutral. It went in with the new boiler and just heats the water exactly the same and no gas being used for that.

         

        You could say we are accidental environmentalists. We didn't set out to go green. It's just that we made choices that were both cheaper and greener. This is why I've written blogs on here to say that it is possible to do both (or at least break even) and this is how it happened.

         

        Peter

         

         

        Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
          Peter E
          Super User
          Peter ESuper User
          Super User
          September 10, 2024

          For the sake of completeness, during the summer when the heating was off and the gas hot water heating was off I could finally see what gas we were using with rhe hob for some of our meals. It turned out to be 2% of our annual total for last year or 160kWh. At 6p a unit that is about £10 a year.  Not much of a business case for replacing that with an induction hob.

           

          Peter

           

          Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
            Peter E
            Super User
            Peter ESuper User
            Super User
            September 12, 2024

            I've added a link to Checkatrade which describes what is Permitted Development (no planning permission required) regarding multi-part Air Conditioners that can be used as Heat Pumps as well. You have to start from ACs otherwise you end up with regulations governing Heat Pumps / ASHPs which is different as these have to be installed under the MCS scheme and can only be used to produce heat.

            https://www.checkatrade.com/blog/expert-advice/air-conditioning-building-regulations/

             

            My type of A2AHP was about £850 new although you can get returned or refurbished units for £100-150 discount with a fully warranty which is what I did. It also connects to the Tuya app through my WiFi which was very easy to set up.

             

            Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
              Peter E
              Super User
              Peter ESuper UserSolved
              Super User
              May 2, 2025

              ​@andykelp 

              I thought I would come back on here and update you with what has happened with our first heating season with an A2AHP.


              It was a learning curve but worked very well, produced  4642 kWh of heat for an electrical input of 1269 kWh giving a SCOP (Seasonal COP) of 3.66 which is slightly better than what the manufacturers said it would do and that figure is for an average of 5C outside temperature and inside of 20C.


              As far as noise is concerned, as it's in the hallway, running a full power on the coldest days its no problem. It has a quiet mode for night-time running and that was slightly more noticeable than we would have liked so I fitted a ‘hush kit’ which I made from plain, white melamine shelves, 100 cm x 30 cm. It only took a few brackets to hold it together and some plastic angle to cover the sawn edges. As you can see it then became a cabinet that my wife populated with various ornaments and plants whereas before it wasn’t something you could do anything with. The cost was about £80 for the bits compared with £700 for the heat pump, an IQOOL-SMART15HP.

               

               

              The top part is a duct that takes air from the left hand side and into the top of the unit where most of the noise was coming from. In the cavity, which has a tilting lid, I put ventilation duct sound proofing material to cut the noise exiting to the left. That was very effective.

               

               

              We also got used to the sounds that it makes over a period of time so we met somewhere in the middle.

               

               

              The heat pump was only one of four sources of heat. The others were Solar Gain 7%, Wood burning stove 23%, Fan heater 3%, and a very much reduced amount of gas from 70% down to 18%. We saved about 7,000 kWh of gas and, without setting out to do so, also saved about £140 on the combined gas and electricity bills.

               

              We’ve always have a wood burning stove but we used a lot less this year as I now only use it to cover the 4-7pm peak where my Agile Octopus rates are the most expensive and the heat pump is off. At practically all other times the heat pump is cheaper to run than gas. The lounge has large windows and the room has a significant solar gain on those sunny but very cold days.

               

              The use of 3% for fan heaters stems from the Agile Octopus rates which go to near zero or even negative when it is very windy in the winter. Effectively we have the wind turbines powering the fan heater which is logically quite a neat solution. They were a bit of an experiment this year, a lot quieter and more powerful than the heat pump on full power so I used them to overheat the lounge overnight which then acts as a short-term heat battery for the morning and the heat pump runs at a much reduced rate until about midday. Sometimes it would cost me nothing for about 20kWh of overnight heat and I can charge the car as well (another 12 kWh).

               

              The remaining gas was used to help the heat pump on the coldest days which has a maximum output of about 4kW. The HP can work mainly on its own to an average outside temperature of about 10C. Below that we need additional sources of heat particularly during the 4-7pm peak when it’s off.

               

              I hope the information is useful. For me the last heating season was very instructive and the A2AHP is definitely here to stay. My wife likes a cabinet in that location.

               

              Peter

               

              Reducing my yearly fossil fuel usage with an EV (-900 litres petrol), A2AHP (-8,700 kWh gas) and Timed Immersion heater (-1,500 kWh gas)
                Chris_OVO
                Community Manager
                Chris_OVO
                Community Manager
                May 5, 2025

                Thank you for the updates ​@Peter E! It’s lovely to see your A2AHP in action and beautifully decorated by the wife!

                 

                I’ve updated this as the best answer to the thread! 

                Renewable energy jokes never get old.
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