Earlier quoted context omitted.
In Scandinavia we use air to air heat pumps. We generally don't have central heating of any kind so we aren't so tempted to try to shoehorn the heat pump into a system based on hot water. Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger. I'm having a Toshiba Polar 35 heat pump installe…
How do you deal with ventilation? Central unit, or a device per room? Or just opening windows? :-) > Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger It might still be worth it to go with water based system if you're going to have underfloor heating. It requires lower water temperature…
:-)