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> Unless you heat with a heat pump. But even then, pumping heat for heating operates on less favourable temperature differences than pumping heat for AC Modern

by fyfy18 8y ago

> Unless you heat with a heat pump. But even then, pumping heat for heating operates on less favourable temperature differences than pumping heat for AC Modern split-system air conditioning units are just heat pumps, and often they are actually more efficient at heating than cooling. For example, Mitsubishi Electric units give out 4-5x the amount of heat vs amount of electricity put in. They will comfortably work at this efficiency down to around -15c (below that the efficiency reduces, but it's still higher than an electric radiator) so are suitable for most climates. http://library.mitsubishielectric.co.uk/pdf/download_full/3767 http://library.mitsubishielectric.co.uk/pdf/download_full/37... I'm rather surprised they are't more common here in Northern Europe, where a lot of residential heating is powered by electricity. Compared to alternatives like storage heaters, they aren't that much more expensive. And you can use them in the summer for the occasional heat wave :)

gandalfian 8y ago
Here in England we heat by pumping fairly hot water through metal radiators, heated by gas or oil. A heat pump produces only lukewarm water at a slow but efficient rate. It is really hard extract the heat out of lukewarm water into a room, often the typical UK room loses heat faster than you can get it out of the water. (Hot water heats the room much more easily). As such the early adopters of heat pumps have expensive items that barely heat their houses and when they try to get more heat out of them in a hurry they become very inefficient. There is almost no domestic air conditioning industry. On the rare occasions it gets too hot we open a window and thank the Gods. Thus there are very few cheap and reliable domestic suppliers of air conditioners for heating. And the air heating ones are tarnished by our experience with the unsuitable water heating ones. So we burn oil/gas or electric storage heaters... Achieving a 300% efficiency and actually being able to heat a poorly insulated UK room just sounds too good to be true.
- jabl 8y ago
  In northern Europe where ground source heat pumps are increasingly popular, houses built with those typically heat via coils installed in the floors. As you say, with only lukewarm water radiators by the windows (the traditional solution for oil/wood/etc. heating) aren't enough.
  - gandalfian 8y ago
    Again it sounds great but I know people whose underfloor coils started to leak at which point the system is written off... Retrofitting anything to an existing solid floor is a nightmare as well. Sorry to be so negative. But that`s why so few of us have heat pumps... Its a shame, the air to air ones sound great on paper, much better than a £600 storage heater but I just can`t bring myself to trust them.

by fyfy18 8y ago

gandalfian 8y ago

Here in England we heat by pumping fairly hot water through metal radiators, heated by gas or oil. A heat pump produces only lukewarm water at a slow but efficient rate. It is really hard extract the heat out of lukewarm water into a room, often the typical UK room loses heat faster than you can get it out of the water. (Hot water heats the room much more easily). As such the early adopters of heat pumps have expensive items that barely heat their houses and when they try to get more heat out of them in a hurry they become very inefficient. There is almost no domestic air conditioning industry. On the rare occasions it gets too hot we open a window and thank the Gods. Thus there are very few cheap and reliable domestic suppliers of air conditioners for heating. And the air heating ones are tarnished by our experience with the unsuitable water heating ones. So we burn oil/gas or electric storage heaters... Achieving a 300% efficiency and actually being able to heat a poorly insulated UK room just sounds too good to be true.

jabl 8y ago
In northern Europe where ground source heat pumps are increasingly popular, houses built with those typically heat via coils installed in the floors. As you say, with only lukewarm water radiators by the windows (the traditional solution for oil/wood/etc. heating) aren't enough.
- gandalfian 8y ago
  Again it sounds great but I know people whose underfloor coils started to leak at which point the system is written off... Retrofitting anything to an existing solid floor is a nightmare as well. Sorry to be so negative. But that`s why so few of us have heat pumps... Its a shame, the air to air ones sound great on paper, much better than a £600 storage heater but I just can`t bring myself to trust them.