[valenterry]

Nope, it's very simple. Just don't try to heat up water to heat the house. Use an aircon. In fact, their efficiency is even better. 4+ is already standard, 5+ is good and there are even models that go beyond 6.

Only problem can be if you have a lot of tiny rooms - in that case it's expensive to install everything.

[darkr]

Those figures are for the unit itself. It takes a lot less energy to heat air than it does to heat water, but water retains heat for much longer.

What matters is the SCOP for the system as a whole.

In a traditional Victorian house with a fireplace in every room, radiant heat will provide far greater efficiency than a forced air system, in which all of that warm air will literally go straight up the chimney.

[valenterry]

> Those figures are for the unit itself.

No.

> What matters is the SCOP for the system as a whole.

That's exactly what my numbers are.

They are the efficiencies for moving the heat-energy from the outside air into the inside air, assuming constant 20 degrees celcius indoor temperature and a specifically weighted outdoor temperature (there are multiple types of SCOPs, depending on the climate-zone and I was refering to the moderate one as it is present in most of middle Europe).

Whether you transfer the heat from the outside air (or some other medium) into the indoor air or into the indoor water does not matter - except that for the latter, you will need to consider that the water has to still transfer the heat to the indoor air, so you need to know how hot the water will have to be to calculate the SCOP correctly for your house.

> In a traditional Victorian house with a fireplace in every room, radiant heat will provide far greater efficiency than a forced air system, in which all of that warm air will literally go straight up the chimney.

What kind of "efficiency" are you even talking about? Can you please provide a definition and some example calculation? Otherwise it's meaningless to discuss.