Comfort: Air/Water Heat Pump vs. Air/Air Heat Pump

Hello everyone,

we are currently planning a single-family house with approximately 160m² of living space based on KFW55. Since we are at the beginning of the planning phase, further details are not yet fixed.

From the very beginning, we have focused on the heating system. Our current favorite is an air-to-water heat pump. The main reason for this was especially the aspect of "warm floors," which is supposed to provide a certain coziness. In many consultation talks, we were confirmed in this point.

However, recently we were rather advised to use an air-to-air heat pump. The reasoning was that the underfloor heating would later lie beneath an approximately 15 cm thick screed layer anyway, and thus an air-to-air heat pump would be preferable because it would heat more directly. It was also said that the comfort without underfloor heating would be comparable.

For us, the question now is which argumentation we can trust. Is underfloor heating preferable to a radiator heating system? Which heating concept provides the house with greater comfort? And do the additional costs of underfloor heating justify the added value?

What is your opinion on these points? Which concept would you prefer, and why?

We would be very happy to receive your feedback.

Thanks & best regards,
matze007

So our neighbors with an air-to-air heat pump are dissatisfied regarding comfort (and consumption). When it gets really cold, quite warm and extremely dry air comes out, and you need a higher temperature to feel comfortable because although the air is warm, the building is rather cold.

I would also clearly recommend underfloor heating for KfW55. Although there is no longer a warm floor in the strict sense, the entire mass of the house is heated here, which provides comfort. Air-to-air heat pumps can become extremely expensive to maintain because the exhaust air of the house is used as a heat source. If that is not sufficient, direct electric heating is used. And that costs.

Pro underfloor heating!
Do you like warm, dry air from blowers? I don't.

Air/air heat pumps can become extremely expensive to maintain, as the exhaust air from the house is used as a heat source

That is imprecise. The air/air heat pump does not necessarily have to be an exhaust air heat pump.
But yes, exhaust air heat pumps are something for passive houses.

Right, you are correct. However, I almost only hear about [Abluftwärmepumpe] when something like that is offered.

Air air heat pump without exhaust air I also find strange. If you heat with hot air, the "old" room air has to go somewhere. So out? It would only be worthwhile at most with a heat exchanger, so air through heat exchanger, supply air first through heat exchanger then through the air air heat pump?