Help with choosing the type of heat pump

Hello everyone,

we are currently planning our single-family house, but still in the initial stages of space planning. I am currently thinking about the type of heating. My gut feeling swings between an air-to-water heat pump and a ground-to-water heat pump. Unfortunately, there is no gas connection; otherwise, that would certainly be another option.

Using a calculation tool, I have chosen the following parameters:

living area 180 sqm (tends to be somewhat smaller)

Electricity (heat pump): €0.20 / kWh
Gas €0.06 / kWh

Specific heating demand 60 kWh/m2*a
Efficiency of gas boiler 96%
Standby losses gas boiler 8%


Heating costs:
Gas heating: €740 / year
Air-to-water heat pump: €497 / year
Ground-to-water heat pump: €488 / year

First question: Are air-to-water heat pumps and ground-to-water heat pumps really that close to each other? Then you can save yourself the question of cost-effectiveness and dramatically shorten the considerations at this point. Or do I have a calculation error here?

What also interests me is the topic of cooling with the heat pump. It works with both variants if provided. With the ground-to-water heat pump probably somewhat cheaper. Does anyone have an indication of how much energy cooling with a heat pump consumes? An empirical value / rule of thumb is sufficient for the time being.

Many thanks for your input.

Please first go to the search, there are lots and lots of threads about .....

Have you ever gotten a quote for the drilling of the SP? For us, it was 15,000 just for that, unfortunately, it was already off the table .... otherwise, I would have found the technology great.
For us, it unfortunately would have only paid off after about 20 years or so....... too long for me

Somehow the calculation looks strange to me. For the air-water heat pump, you have a seasonal performance factor of about 4.3. A sporty value that only a few air-water heat pumps achieve; a brine-water heat pump manages that easily. For me, the consumption values are way too close together. How do you get these numbers?

The 20 cents for the heat pump electricity only applies with a special heat pump tariff that requires a second meter for the heat pump, which then costs extra.
The brine-water heat pump is probably already more expensive, but it also receives more subsidies. If you have a larger garden, a ground collector would be an option. Some people in [EL] do that, then the geothermal heat pump is not really expensive anymore.

20 cents only with a second meter is clear to me. But it probably also makes sense for a heat pump heating system. We currently live in a rental with an air-to-water heat pump and a second meter, so I have assumed the 20 cents we currently pay plus a small surcharge. I consider the additional costs negligible or they compensate for themselves with a planned photovoltaic system.

I calculated the whole thing with a tool I found on the internet. Maybe it spits out nonsense though. The results surprised me too, which is why I started this thread.

I have also thought about a geothermal collector. The property is large enough (about 700 sqm). The house and garage will occupy < 150 sqm of floor area.

Second meter and photovoltaic exclude each other. The heat pump will not be able to use electricity from it. Such a meter typically costs 80-100€ per year, making up about 20% in your calculation.

Brine is easily 20% more efficient, the consumption costs are unrealistically close to each other. However, it all depends on the drilling costs. Subsidies are much higher for brine, so it can already be worthwhile.
It's not just about costs. Brine can provide passive cooling if desired, and you don't have an ugly (outdoor installation) and possibly loud/vibrating device on the house.

I consider the additional costs negligible or they are compensated by a planned photovoltaic system

With that, the second meter then simply makes no sense anymore.

For a normal air-to-water heat pump, I would rather estimate an annual performance factor of 3.5, for a ground-source water-to-water heat pump rather 5.0, so per kWh of electricity a factor of 3.5 or 5.0 in heat. That results, if you only consider your heating energy demand of 10,800 (180*60), in a little over 3,085 kWh for an air-to-water heat pump, just over 2,100 kWh per year for a ground-source water-to-water heat pump. Hot water is additional. Since you only work with one meter because of the photovoltaic system, the whole thing is then calculated at 26 cents.
Just to illustrate, roughly estimated with the back of the hand.