Would you take an air heat pump again? Looking for alternatives to air heat pumps

With a trench collector, it makes sense to engage very thoroughly with the subject yourself. Then it works very well and inexpensively as a DIY project, and you can better distinguish sales talk from well-founded knowledge.

generally always get information!!! Sensitive topic... someone wanted to sell us a 4 kW drilling for a 6 kW heating system. Contact the [Bundesamt für Geologie (?)] - they have detailed maps of soil conditions and heat extraction capacities etc., read up on underfloor heating etc.

f-pNo can you tell me how big your house is and what heating system you have installed? May I ask what the geothermal system cost in total?

Our house, including utility room and storage room, is 172 sqm.
We have installed a Vaillant Geotherm Plus VWS 82/3 and two boreholes with a capacity of 7.8 kW.
The cost for the drilling all in – i.e. including filling with brine concentrate etc. – was 7,126 euros. The company is very reputable in our area, based in the Eifel region and, to my knowledge, operates within a radius of 150 km.
I cannot specify the cost for the Vaillant system exactly, since it was included in the house price (the drilling had to be paid for separately).
In the consultation, our general contractor said that geothermal energy would cost between 12,000 and 14,000 euros all in (including the drilling).

The remark from is correct:
We built a KfW 70 (according to the Energy Saving Ordinance 2009). For this, 36.5 cm Ytong was used on the ground floor and 30 cm Ytong on the upper floor.

Just a small side note, although I don’t know whether this is normal or how it relates to the heating system itself.
Up to moving in – including the heating phase for drying the screed – we consumed 1,300 kWh of heating electricity. This amounted to about 275 euros in costs during the construction phase. I mention this because two colleagues told me they had electricity costs well over 1,000 euros just for drying the screed.[/QUOTE]

We had 2300kWh for the screed drying, but it was heated directly with electricity for that. So it has little to do with geothermal energy. I also have a Kfw70 according to the 2009 Energy Saving Ordinance. However, with a Tecalor 6.8kW heat pump. What does "drill holes for 7.8kW" mean? There are so many differences: probe length, probe type, filling (many still use one with poor thermal conductivity as pressing material), soil etc. And there are different calculation models. Some standard calculations often assume too few operating hours, for example. For the drilling, not only the maximum power but also the amount of energy extracted over the year is important.

For us, the brine in the winter did not go lower than about 5°C on the return. Also, how well the heating was adjusted plays a role. For me, an individual adjustment of the heating curve and hysteresis also helped, so at the moment I can keep the temperature in the house exactly right without individual room control.

We had 2300 kWh for the screed drying, but it was heated directly with electricity for that. So it has little to do with geothermal energy. I also have a KFW70 according to the 2009 Energy Saving Ordinance construction. However, with a Tecalor 6.8 kW heat pump. What does "boreholes for 7.8 kW" mean? There are so many differences: probe length, probe type, filling (many still use a press material with poor thermal conductivity), soil, etc. And there are different calculation models. Some standard calculations, for example, often assume too few operating hours. For the drilling, not only the maximum power but also the amount of energy extracted over the year is important.

In our case, the brine in the return line in winter did not go below about 5°C. Also, how well the heating was adjusted matters. For me, a separate tuning of the heating curve and hysteresis helped somewhat, so at the moment I can keep the temperature in the house exactly right without individual room control.

That's true – now that you mention it, I remember it again. Our screed heating phase was also done only with electricity. Our general contractor once told us (since at the time we thought geothermal energy was used for that) that heating up the screed with geothermal energy could possibly lead to the borehole cooling down.

The specification "boreholes for 7.8 kW" I took from the invoice. I can't remember the exact depth anymore – only that a double borehole was done. I believe 120 m was mentioned once – it might be that this was the total for both boreholes or each individually. It's been quite a while – the drilling was done about a year ago. Damn, age is showing – memory is fading. The boreholes were filled with 95 liters of brine concentrate.

I can't say anything about the other points – I'm still too much of a layman and I'm not very familiar a) with the Vaillant yet and b) with the different adjustment and analysis options. What I want to say is – perhaps there are even optimization possibilities for us.

I hope the brine concentrate is in the pipes. The boreholes are grouted with something similar to cement (but special stuff made especially for that) to ensure they have as much surface contact as possible with the pipes and that heat is transferred. There are significant differences here in terms of price and conductivity (unfortunately better is also more expensive).