Is the surcharge for an air-to-water heat pump justified compared to gas?

Hello everyone,

I need your assessment regarding the heating choice. We (2 adults, 4 children) are currently in talks with a general contractor for a house, which sounds quite good so far, the construction service description is okay. We are not planning to reach a specific KFW standard but will end up somewhere between 70 and 55. The heating load calculation is, of course, not finished yet as the contract is unsigned.

The standard offering from the general contractor includes:
Gas heating: Vaillant auroCOMPACT VSC S 206/4-5 190 condensing compact unit
Rated at 20 kW (wow, why?)
Includes a 190L hot water storage tank, packaged with 2.5m² solar thermal system

Alternatively, he offers an air-water heat pump credited against the gas heating and solar thermal:
Thermia iTec Plus with 9 kW capacity, cooling function, and 300L hot water storage next to it.

Actually, I would prefer going towards the heat pump, but:

The surcharge for the heat pump solution is a hefty €8,100. That way, we wouldn’t need a gas connection...
Maybe I’m mistaken or it doesn’t add up to go for the heat pump?
Even if one achieves a COP of 3.5 or 4 with it, the extra costs of €8,100 minus €2,500 for the gas connection = €5,600 will only pay off very, very late.
At €0.30 per kWh electricity, with 10,000 kWh annual consumption and a COP of 4, we would have costs of €750. At a gas price of €0.10, costs would be €1,000. Difference thus €250/year, the extra costs amortize (disregarding the solar thermal) only after 22 years.

Is that correct, or do I have a screw loose / error in the calculation? I tend towards gas with this extra cost, possibly with an additional hot water storage tank.

Thanks and best regards
SoL

Addendum: Even with permanent prices like now at 13 cents, the payback would only occur after > 10 years. I secured the 10 cents in January for 2 years for the existing house...

You are right. If you do not necessarily want KFW 55 or lower, which would not make sense anyway, the heat pump is currently still too expensive. It is, and this must also be said, also more prone to maintenance.

You are right. If you don’t necessarily want KfW 55 or lower, which wouldn’t make sense anyway, the heat pump is still too expensive at the moment. It must also be said that it is more maintenance-prone.

Sorry Karsten, but that simply isn’t true. Once installed and properly adjusted, it practically requires no maintenance. On the question: No, the price is NOT justified. Not at all. Not in the slightest. And the gas heater is additionally completely oversized. What difference does it make if you have the heat generator removed from the scope of work? Be sure to include a room-by-room heat load calculation including the design of the underfloor heating based on the heat load calculation.

Regarding the question: No, the price is NOT justified. Not at all. Not in the slightest. And the gas heating system is additionally completely oversized. What difference does it make if you have the heat generator removed from the construction service specification?
Be sure to include a room-by-room heating load calculation including the design of the underfloor heating based on the heating load calculation.

Is the note that the calculation is carried out according to DIN EN 12831 sufficient? Excerpt from the construction service specification:

All rooms on the ground floor and attic/upper floor are equipped with underfloor heating and thus provide pleasant, cozy, and comfortable warmth in your home. The warm water underfloor heating system consists of heating loops on carrier plates and the required insulation; the piping is made of cross-linked plastic pipe. The length of the individual heating circuits as well as the laying distances are carried out according to DIN 4701, the energy saving ordinance verification, and the heating load determination according to DIN EN 12831. The underfloor heating is designed so that a heating system with low flow temperatures can be connected, thus enabling operation or conversion to the use of renewable heating systems.

Removing it would affect the "gross production costs," exactly how much I would need to inquire about, but I suspect it is little.

Thanks
SoL

The surcharge for the heat pump seems excessive. This could be translated to mean the general contractor is not keen on it. If you can clarify this with the general contractor or assign it yourself, I would always tend to go for the heat pump. Otherwise, you have to consider whether you want to force the general contractor to do something he doesn't want to... in the worst case because he can't do it properly.

What is the deal with the cooling function? Do you need or want it? If not, can it be left out?