Gas, heat pump, and solar for a single-family house?

Wouldn't a domestic hot water heat pump also work in the case of the [TE]? Would it therefore be possible to do without the solar?? And also reasonable from a cost perspective?

In case the building stands over the winter and can freeze/dry—would that then be a problem without controlled residential ventilation, aside from comfort?

Heating load calculation - Attention, layman's explanation: based on the specific construction project, location, individual comfort temperature (for the entire house, for individual rooms this is only possible to a limited extent - max 2-3 degrees difference), etc., the heating load for the house is calculated. Based on the data, the right heating system and, for example, spacing of the underfloor heating can be chosen.

Gas and controlled residential ventilation with heat recovery I consider a good because simple solution. Controlled residential ventilation also provides very good comfort beyond the first two years.

The solution should be cheaper even by an external general contractor than the aforementioned patchwork from the uncle at the "friendship price" and quite certainly with lower follow-up costs.

I have gone through a similar learning process. We have now ended up with an air-to-water heat pump (Luft-Wasser-Wärmepumpe). I am adding the controlled residential ventilation with heat recovery mainly for comfort reasons. With the planned standard insulation (according to the construction specifications, so nothing particularly special), we also achieve KfW70. The alternative would be gas and solar thermal energy. I asked intensively about this, but the heat pump that the builder normally installs (which other people are already living with, and they manage somehow) is not more expensive (rather cheaper) in terms of acquisition costs than gas + solar thermal energy (assumption: gas connection only for heating, which then is eliminated, cooking is done electrically). Without the obligation with solar thermal energy, gas would probably have been my choice, but that is simply not possible... or does not lower the investment costs.

I would definitely not build two systems. Underfloor heating is different from the traditionally known radiators, but different does not necessarily mean worse. All in all, comfort and well-being in a modern (efficient) house with underfloor heating (and ideally controlled residential ventilation) is likely to be significantly higher than in an 80s new build with radiators under the windows. Don’t let yourself be driven crazy by that.

So take the solution that is common on the market, that is simple (not two systems), and that can be implemented legally. From my point of view, that is still the heat pump. Either air-to-water heat pump or ground-source heat pump (surface collectors if you want to allocate the area permanently, or geothermal energy if you want to do the drilling and can afford it).

The heating load calculation is also important for the correct sizing of the heating system and, for example, the heat source in the case of geothermal energy. Most technologies are only financially worthwhile if they are really well coordinated with each other - for example, photovoltaics and a brine-water heat pump designed for self-consumption.

Is the energy standard of the house actually sufficient for a heat pump? I can remember colleagues who have to heat expensively with an electric heater in winter because they found the technology "interesting" in 2008, but the building envelope simply does not fit.

Is the energy standard of the house really sufficient for a heat pump?

Sure. Double-brick masonry fits, it would probably result in KfW 70 rather than KfW 85 anyway; as long as the house is not supposed to be built on bare branches, of course

I remember colleagues who have to heat expensively in winter with an electric heating rod because they found the technology “interesting” in 2008, but the building envelope simply doesn’t fit.

They probably have the air-to-air heat pump, which can only be operated economically in a passive house. If it is an efficiency house 70 or 55, the heating rod comes into use.

Rhenish greetings on the go