ᐅ New construction heating system?

We are currently in the middle of planning our new build and are now selecting the heating system. We have read that it is now possible to heat using geothermal energy, but we have no experience with it. How exactly does it work, and would you recommend it to us?

Hello Eve,

When it comes to geothermal heating systems, it’s important to distinguish whether drilling is required or if surface collectors are used.

We also considered drilling, but quickly decided against it after a nearby town experienced a failed drilling project. The drilling caused ground shifts, which in turn led to damage in several houses (cracks).

If the ground conditions are uncomplicated, I would still consider heating with this technology.

In general, you shouldn’t purchase your heating system based on assumptions, but rather choose it according to the building’s heating load calculation.

Best regards,
Dirk

Geothermal energy works through a heat pump. The process is the opposite of a refrigerator --> the heat pump extracts heat from the surroundings (borehole or ground area) and transfers it into the house (simply explained).

eve27 schrieb:
We read that it is now possible to heat using geothermal energy, but we have no experience with it. How exactly does it work, and would you recommend it to us?

As nordanney wrote... You can basically find the answer to your question using any search engine of your choice. Links are not allowed here, so you’ll have to do the googling yourself :P

Drilling: Requires a building permit / planning permission, is expensive, and not always feasible...

Surface collectors: As a rough estimate, you need about the same area in your garden as your house covers. In that area, a long pipe is laid in shallow ground (just below the frost line) in a loop, through which a heat transfer fluid circulates. You cannot build on top of it or plant deep-rooted trees there. However, it is relatively cheap and basically straightforward (you might even install it yourself, a small excavator is sufficient).

Both options work in normal soil or groundwater layers, with some detailed differences...

Would I recommend it? It depends on the soil conditions. Personally, I would rather not go for it. I would prefer an air-to-water heat pump and a well-insulated house. Or a gas condensing boiler, which unfortunately requires other measures (if you are building in Germany), so an air-to-water heat pump might then be more economical. It depends.

Hope this helps.

Do these pumps also operate reliably during a cold week with an average temperature of -20°C (-4°F) and provide enough energy for heating and domestic hot water? It is often mentioned that they "only" work properly down to -5°C (23°F)...

Air source heat pumps tend to become quite inefficient in those conditions. All types can provide heat, but air source heat pumps then rely on the electric heating element, meaning you have to use expensive supplemental heating.

However, this is not a general rule – it always depends on the system design, model, and configuration.

Ground source heat pumps don’t have any issues with temperatures because they operate independently of the outside air temperature—in the relatively "warm" ground, which over time can also freeze. I believe that extended periods of frost could potentially cause problems as well (just a theory) 😉