MCS heat loss calcs and Catch 22

jswhite · 2022-08-15T08:47:27Z

I had a massively oversized ASHP forced on me because with the silly idea that the device should be big enough to heat the whole house. We have lived here for 26 years and never heat bedrooms, hallways and only the shower room on the coldest days and then for only an hour. I told them many times.This was dismissed as irrelevant, I couldn't have a smaller heat pump, my right to chose had been removed by the MCS edict. About five different sources all trotted out a scripted justification 'What if you sell your house?' Shock horror, the new owner would have to chose their own heating, bathroom furniture and kitchen wallpaper etc.!But no, the right to install a 16KW Samsung HP against my wishes was embedded in the MCS rules as though it was a statutory law. It is also a sleight of hand because previous oil boilers are often calculated to have enormous BTU sizes but they are not made to be incredibly inefficient when not used at capacity.So I then had an oversized heat pump (the heat loss calculations suggested 12960KW total heat loss, so of course they fitted one 20% bigger). When used to heat the areas that I wanted to heat (two rooms) it burned through crazy amounts of money long before this years price rises came along. The DHW was even worse, decorated with three pumps to waste electricity and a midnight raid to burn off legionalla (which is not necessary for domestic systems - it took ten minutes to look this up and find a report with this important detail). The fact is that 200 litre tank to supply one kitchen tap is a travesty.I switched the whole device off at the mains last April and has not been used since. The benefit to the environment is that we have been pushed back into a medieval structure with no heating or hot water.We have no choice but to replace th HP with a much smaller unit 4 or 5KW to heat two rooms with UFH and one radiator. No DHW.I got the MCS spreadsheet for heat loss and found that my calculations produce a heat loss figure of 8500KW. The installer was persuaded to recalc the heat loss because they had not included a kitchen but subsumed that area into a living room. They had also mis-measured several rooms and included an outside workshop!. Then with all those changes rectified the re-done calculation came to 12,500KW - 465KW lower than the first one). I might be making a mistake in my calcs but they will not show me the assumptions or variables they used - isn't that a surprise?.I complained the HIES - they said EPC was used to decide heat pump size. Wrong, Rude and pathetic.I complained to NICEIC, they gave me two weeks home work to do providing lists, photos and emails etc, and then said it was not in their remit.I asked HIES to give me access to the Ombudsman but they said they wouldn't because they didn't want to 'falsely raise my hopes' - condescending little..........So we are facing a winter with either (i) an oil filled electric plug-in radiator for one room in the whole house. (ii) Selling up a house destroyed by this exercise (no kitchen because we removed ours to put a new UFH circuit in ready for the HP. We can't afford a new one if we have to pay for a different heat source. Or (iii) burning our way through three or four thousand pounds of electricity on an income of less than £17K to heat two rooms!.And the much faunted RHI rebate came in at £29 every three months on condition that we pay £60 every three months for a fatuous maintanance contract. So that was cancelled.What a mess. Any advice would be greatly appreciated - John.

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Air Source Heat Pumps (ASHPs)

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JamesPa

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10/06/2023 2:47 pm

Posted by: @kev-m

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IMO the majority of houses in the UK are not special cases and a good, experienced ASHP heating engineer should be able to look at a house, ask a few questions and give an adequate estimate of sizing cost that is good enough for an initial quote.

Definitely. Start by asking for the current annual consumption (or better still smart meter readings) and heating pattern. That will give an estimate which will, in many cases, be better than the current method and, imho, should in every case be used to sense check the current method and in some cases should be used instead of the current method.

This post was modified 3 years 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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