Does anyone have one?

I have a Mitsubishi Ecodan (UFH) fitted in a new build, constructed from SIP, tripple glazed and MVHR. You need to ensure that you improve the insulation and prevent any air leaks.

How well do they perform? How hot is the water?

It works very well, mine is in weather compensation mode with flow temperatures around 30C. Hot water is excellent, just like a gas boiler.

What are the running/servicing costs

I’ve not had mine serviced yet but expect the cost to be higher than a gas boiler (£250). Mitsubishi do service plans that also cover parts.

What downsides are there?

You need to get a proper heat survey done to get the sizing right (check out heat geeks on YouTube) and registered fitters seem rather thin on the ground. My current COP is around 2, not the 4 I would like but I’m very happy with the system.

Finding a good fitter and the room needed to fit the kit inside. In winter the internal pump circulates water to prevent the air pump and pipes freezing (can be switched off) which causes some issues if placed in an old airing cupboard near bedrooms.

We are also looking at having solar panels installed to potentially power the heat pump, has anyone done this?

I’ve just fitted 11 solar panels (all I could fit) and two batteries so still in its infancy, the air source heat pump eats them up very quickly but overall I’m impressed.