Air heat pump & photovoltaic or geothermal system, which providers?

Hello dear forum users!

This spring our house construction is coming up... we are currently sorting offers from construction companies and selecting various things. We planned our house (226 sqm living space excluding basement) with our master builder at the end of last year. Everything has been approved by the municipality and the funding has also been applied for.

Now we are facing the big question about the heating system. According to the energy certificate, our house has a heating energy demand of 10,000 kWh per year. In various forums and also from companies at trade fairs, one often hears that geothermal heat pumps are supposed to be more efficient than air heat pumps.

My question now is what it looks like when combining an air heat pump with photovoltaics and comparing this to a geothermal heat pump system. What is better in the long run? We have received an offer for an air heat pump & photovoltaics, which actually looks okay.

So, leaving aside that the company is still relatively unknown, which system would you rather recommend?

I would be very grateful for answers!!

Hello,

... Everything has also been approved by the municipality and the funding has also been applied for. Now we face the big question about the heating system.

A little late, but not too late.

... Our house has a heating demand of 10,000 kWh per year according to the energy certificate.

This value is useless, since Energy Saving Ordinance/KfW figures merely serve qualitative comparison purposes (public-law evidence). For the planning/dimensioning of heating systems, it is even inadmissible to use these values (DIN 4701-10)!

... you often hear that geothermal heat pumps are supposed to be more efficient than air heat pumps.

That is correct. However, the better insulated a building is, i.e., the lower the actual demand, the less significant the efficiency of the system becomes.

... My question now is how it looks if you combine an air heat pump with photovoltaics and compare this to a geothermal heat pump system. What is better in the long run?

There is no general answer to this; it must be calculated (or have calculations made) on the basis of the specific framework conditions independent of sales.

... We have received an offer for an air heat pump & photovoltaics, which actually looks okay.

What does "okay" mean in this context? According to which criteria or on what basis has it been evaluated? If not even the actual demand (power, energy) for heating and hot water is known, making a decision is like looking into a crystal ball. In addition, especially for air heat pumps, the COP and performance curves over the entire operating range are of essential importance.
Best regards.

@€ruo

Thanks once again for your answers!

So, in our energy certificate, a total heating load of 7.7 kW is specified. I am unsure about the required power for hot water, as this is not clearly indicated. It should be around 3.7 kW.

Additional data about our house:

Heated gross volume: 932m³
Average U-value 0.25W/m²K
Brick 30cm ceramic
Insulation 20cm

What other data do you need so that you can help me a bit?

Hello,

...Also in unseren Energieausweis ist eine totale Heizlast von 7,7kw angeführt.

The value is not usable! An exact heat load calculation according to DIN EN 12831 (detailed method) is required.

...Hier dürften es 3,7kw sein.

How does this number come about?

....Welche Daten sind noch nötig, damit ihr mir ein wenig helfen könnt?

The actual demand (energy, power) must first be known.

Best regards