To heat or not to heat an unused basement in a new building?

That sounds a lot like poor planning and "a basement is a must, whatever for." My contribution won't help you, dear Hubert, but many others who are considering whether to build with or without a basement.

Insanely low costs with you. I tried it the other day at around 5-10 degrees outside temperature. Without the basement about 15-18 kilowatt hours, with the basement about 30 / day. And I only had the ERR downstairs on level 2!! Although I don’t know if there is a difference in power consumption between level 2 or 6, because the flow temperatures for the upper floor are about 30 degrees anyway and for the basement they are just mixed ...

Hello Hubert

that sounds like your ground probes are undersized.
I have 2 x 75 meter boreholes. And, due to my wife, who tends to get cold quickly, the house is always between 22° and 23° warm.

Steven

That sounds a lot like poor planning and "a basement is a must, no matter what." My post won't help you, dear Hubert, but many others who are considering whether to build with or without a basement.

Sorry for Hubert, but I thought the same.... large living space + huge basement that you don't need and now have to worry about heating.

Doesn't fit together.

I tried it the other day at about 5-10 degrees outside temperature. Without basement approx. 15-18 kilowatt hours, with basement approx. 30 / day. And I only had the ERR downstairs set to level 2!! Although I don't know if it makes a difference in terms of electricity whether it's level 2 or 6, because the supply temperatures for the upper floor are about 30 degrees anyway and for the basement they are just mixed ...

I don't think such a short "test" is that meaningful yet. You first have to warm up the entire mass in the screed, walls, etc. Or how long did this test last?

If it is necessary to heat, then I just do it ... But is there a clear statement that says: Yes, you have to heat, or no, you simply don't have to ... ?? Or just ventilate?