Looking for some advice – no viable installer/system – I'm stuck

Redguy17 · 2025-02-04T12:00:54Z

Hello Fellow heat pump/ sustainability fans. I am trying to get my self the so called ‘holy trinity’ of Solar, Batteries and a heat pump. I have had solar for 2 years now and love it. It’s a 5.5kw array with 6 panels facing south and three facing west. WE are pretty high users with daily averages of 10 kw plus. I’m looking to install 17 kw of battery storage to help tide us over in the winter months, charging up on the cheap rates on octopus go tariff. I’ve been making enquiries for over six months and have been fobbed off by many installers who , I assume, are just to busy o be bothered to quote. I’ve had two companies come over to do heat lost assessment and give me quotes for a heat pump. I wont name names but I had a you tube famous company come out to do a heat loss survey and before the guys even stepped into my house he was negative trying to dissuade me on cost grounds. My house is a typical 1950’s semi about 120 meters shared with 300 mm loft installation not wall insulation and is currently heated with a combi boiler and my wood burner. Even though I have a normal garden he couldn’t find a single place to locate the heat pump that would fulfil his companies guidelines for heat pumps, not to mention that they only work with one supplier which means I could not wall mount as I had wanted and had to find a place in my garden. The other company that came out is a local firm but they have designed the system to run at 65 degrees at -2 Celsius , not upgrade the rads and have a ‘ buffer’ tank. From my research these are red flags. So unfortunately for me it seems I’m stuck between heat nerds who say computer says no and local cowboys who want to stick any old thing in. Has my heat pump journey ended what would you guys do ? Thanks Redguy 17

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JamesPa

(@jamespa)

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Joined: 2 years ago

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06/02/2025 1:29 pm

Posted by: @redguy17

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my annual gas ussage is 26786 KwH( heating and hot water)

bolier is over 15 years old ( estimates 87% efficent)

i work at home so heat is on all day every day usually to 19 degrees

20% of the house ( a bed room and ensuite) are currently heated with electricity.

Currently during October to February we use about 6 tonnes of wood as wood burner is on from 6 am till 6pm most days.

Wow, thats a lot of gas - you said 120 sq m is that the total floor area or just the ground floor footprint? For comparison my 200sq m detached was about 20kWh gas consumption/7kW loss.

6 tonnes of wood adds about another 24MWh making 50MWh consumed in total on heating plus hot water, even without the electric. If we assume 85% efficiency thats still 43MWh, which equates to somewhere between 14 and 20kW loss. Do you have a lot of long showers or keep the windows open a lot?

Posted by: @redguy17

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PS. my pipe work is already 28mm . heat loss was calculated as 9.8 and 10.9 respectively. a Vaillant aro therm plus

10/12 kw double fan unit has been suggested by both.

If the consumption figures are correct then 9.8/10.9 appears to be an underestimate for the loss. However lets run with it for now.

The Vaillant double fan is a bit of a monster size wise, but there are several single fan models doing up to 12kW. Mitsubishi for example do 11.2 in rather neat single fan format. Others do single fan also but sometimes wider. it might be worth contacting someone who does one or two of these?

I would be very concerned about your consumption though, unless there is an explanation buried in my questions above. It seems just too high which makes me wonder where the heat is going! Perhaps you can shed some more light by answering the questions above?

This post was modified 6 months ago by JamesPa

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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