ᐅ Ground source heat pump for a small single-story detached house

blackarrow1990 schrieb:

Is there a guide or literature on which heat pump would be best suited for such a small construction project? Thank you.

It’s not only about the size of the house but mainly about good insulation and thus a low H,T-value (transmission heat loss). The better the H,T-value, the lower the heating load of the house. For example, a poorly insulated house with 120 m² (1290 sq ft) can have a higher heating load than a well-insulated one with 160 m² (1720 sq ft). Try searching for Trenchplanner and trench collector on Google. With this tool, you can calculate your approximate heating load based on your house data and the H,T-value. Only then can you say whether an air-to-water heat pump can efficiently heat your home. Alternatively, you can provide the following values for your house, so discussion here can be more precise and the heating load easier for everyone to understand.

H,T-value
desired average temperature
envelope surface area (A)
heated gross volume (Ve)
ventilation (controlled mechanical ventilation, decentralized, window ventilation)

We installed a ground source heat pump with a horizontal trench collector on a 410 m² (4410 sq ft) plot (160 m² (1720 sq ft) heated area) and it worked without any issues. So deep drilling is not always necessary.

Regarding subsidies: As far as I know, funding for energy-efficient heat pumps ended at the end of 2020. That means you need to weigh the additional costs of a ground source heat pump against possible extra heating costs of an air-to-water heat pump. If you contribute your own labor, a ground source heat pump does not cost significantly more than an air-to-water heat pump (about 3,000 euros if a trench collector is installed).

Procedure:
1. Insulation -> Has the greatest impact on heating costs
2. Design of the underfloor heating -> If done incorrectly, it affects the heating system’s efficiency
3. Heat generator -> Heat pump, gas heating systems can all heat effectively; it depends on personal expectations regarding future energy prices

Recommendation:
Calculate the heat load for each room according to DIN standards, specifying the desired temperature for each room.
Have the underfloor heating design calculated by a specialist company; this costs a few hundred euros but usually delivers the best results.

In bathrooms, cover a large surface area with small spacing, possibly also consider wall heating.

Size the connection to the heating circuit valve (HKV) sufficiently to ensure adequate supply on the upper floor.

Heat generator
Heat pump: modulating with the lowest possible minimum output; maximum output should not exceed the calculated heat load.
BWT: smallest possible minimum output (1.8 to 3 kW), maximum output not exceeding the calculated heat load.

I wouldn’t consider a strict comparison (financial calculation of the options) as a given necessity. What do you want? What can you afford? (What I mean is: no one needs to be the richest person in the grave …)
And consider the overall resource demand as much as possible (purchase, operation), taking into account the desired level of comfort.
Try to understand the fundamental differences, then you will be better able to decide and say what you feel comfortable with.

Thank you very much for the answers, they are already helpful to me.