ᐅ Which Heating System for Maintaining a Room Temperature of 23 °C

Hello community,

For the past few days, I have been researching current heating technologies and feel that it raises more questions than answers, which is why I am now turning to you with my questions in the hope that experienced users of this system can provide some answers.

My wife and I would like to build a KFW40+ house with about 130 sqm (1400 sq ft). The house will have an unobstructed southern exposure, meaning plenty of sun in both summer and winter. A photovoltaic system will be installed on the roof. At the moment, we are leaning towards a prefabricated house, but we are still in the decision-making phase.

We both currently live in an apartment with underfloor heating and a gas boiler, and we find the warmth emitted by the underfloor heating very comfortable. I have set the central room temperature to 23°C (73°F) on the gas boiler because we both like it quite warm, although this can be adjusted downward locally with thermostats.

With a prefabricated house, the Proxon air-to-air heat pump is usually offered as the solution on the market. However, further research reveals advantages and disadvantages of this technology, as with any topic. I have read so far that many heat their rooms to 20–21°C (68–70°F) using the air-to-air heat pump. However, I have not yet found out whether it is possible to reach 23°C (73°F) with an air-to-air heat pump without the use of auxiliary heating panels. The question is also what power consumption these auxiliary panels have. The sales representative of the prefab house provider mentioned that with these auxiliary heating panels, the room can be warmed quite quickly (within 5 minutes). Ultimately, the whole setup works like a hairdryer. But if I hold a 2 kW hairdryer in a room, I don’t notice a significant difference after 5 minutes.

Question: Can I achieve a room temperature of 23°C (73°F) without auxiliary heating panels, even in larger rooms? What is the power consumption of such an auxiliary heating panel? Does anyone have additional consumption data for this heating solution? How does it perform on cold winter days? Ultimately, it is about the indoor climate, and 23°C (73°F) is not always the same 23°C (73°F), which I understand.

As an alternative, it seems that an air-to-water heat pump is also an option. In terms of efficiency, this is said to be similar to the air-to-air heat pump but more expensive to install because pipes must be laid. However, since the flow temperature is lower, it should be more economical to operate. Is that correct? With this type of heating, there should be no problem achieving 23°C (73°F) even in larger rooms, right? Does anyone also have consumption data here? Of course, it depends on individual behavior, which I understand, but figures can help build a sense for it.

Cooling in summer is not possible with this heating system but should be possible as an add-on with an air-to-air heat pump. Does a KFW40+ house get very warm in summer?

Thank you very much for your help and information.