I’ve just passed my first winter with a Mitsubishi ecodan 8.5kw.
My home:- 60’s built semi in the Midlands, dormer loft conversion and ground floor living room single floor extension in the 70’s. I’ve just done a 2 story 42% extension having flattened the garage. Not the best-insulated house. The top floor needs totally rebuilding with modern insulation for one, 1980’s blown double glazing around most of the house, finlock concrete gutters bridging the wall cavities etc. I do have 300mm of insulation in all the loft areas I have access to and the cavity wall has been filled. I needed a new boiler but also needed 10% green energy for the house to pass the planning requirements.
So I took a punt on an ASHP. There were a few sites (here included) that scared me with stories of massively expensive bills and cold houses, but I think that this must be because of people not changing their heating mindsets.
Aside from oversizing 4 of my radiators, the expense was purely fitting and commissioning.
Obviously through the coldest snap (-12 for two nights), the meter span. But I am still set to break even on my energy assumption (I got up to £850 in credit before winter, on an annual £1300 energy bill). Not very impressive… till you take into account that my home is 43% bigger than it was last year and that we run at 21° this year and last year was 20°.

Very very happy. If I had a new build, with perfect insulation all around, I’d ASHP all the way!

I’ll post again on my end of year figures.

Tom Unsworth