If it doesn't work, it will be a gas boiler with solar thermal. An air-to-water heat pump is actually not an option. I find it somewhat pointless.
A properly designed air-to-water heat pump in a "warm" area can make 100% sense. However, I would try to meet the requirements of the Energy Saving Ordinance with a gas heating system and controlled residential ventilation.
A properly designed air-to-water heat pump in a "warm" area can make 100% sense. However, I would try to meet the requirements of the Energy Saving Ordinance with a gas heating system and controlled living space ventilation.
When do I need the air-to-water heat pump the most? Right, when it is really cold. But then the air is also cold. Thus, less efficient. But yes, if brine is not possible then gas boiler.
When do I need the air-water heat pump the most? Right, when it is really cold. But then the air is also cold. Therefore, less efficient. But yes, if brine is not possible, then gas boiler.
And when does it really get cold in most parts of Germany? Hardly at all for years. Even my moderately insulated house requires a maximum heating load of about 7.5 KW in deep winter at -12 degrees. If I had underfloor heating, I would have switched to an air-water heat pump. 98% of the days (and nights) we are above freezing. An air-water heat pump is still efficient enough there. Of course, it looks different on the Zugspitze.
When do I need the air-to-water heat pump the most? Right, when it’s really cold. But then the air is cold too. So, less efficient. But yes, if brine doesn’t work, then gas boiler.
Well, you have a heating limit temperature of about 12 degrees. A good air-to-water heat pump then operates with maybe a performance factor of 5. The problem is only with temperatures below -10 degrees, depending on the heat pump. Then the COP drops, but you can check how many days per year that actually is. If you consider a few parameters, it can definitely make sense. But I don’t want to convert anyone.
With good arguments, I would not be opposed to an air-to-water heat pump. However, one thing is not acceptable: an outdoor unit. We find such things totally ugly. And such a thing does not go in the garden. Solutions with an indoor unit would need to be investigated to see how the noise situation is.