Heating concept for new construction based on gas

Hello everyone,

after reading quite a bit in the forum about the different types of heating systems, I am increasingly convinced that I would like to install a gas condensing boiler. The concept of air heat pumps does not convince me in the case of low temperatures, and ground or water heat pumps are not allowed on the targeted property.

My current idea would therefore be as follows: gas + support of hot water preparation through photovoltaic + ventilation system with heat recovery.

The house will be about 150 sqm. I have a few questions for you:

- Does the combination make sense?
- Why are solar thermal systems used as standard? Do they have a better efficiency for water heating than photovoltaic? The advantage of photovoltaic would be that you can also use the electricity for other things...
- How about the costs? Is photovoltaic more expensive than solar thermal? What does a ventilation system with heat recovery cost for 150 sqm?

Thanks in advance for your valuable help in this jungle.

Best regards
Mr. Stein

Good day Mr. Stein,

The concept you mentioned generally makes a good impression regarding the combination of a gas condensing boiler for heat generation and the ventilation system including heat recovery. This should basically allow relatively low fuel costs and a good indoor climate, although no one can predict the medium- and long-term development of gas/oil or electricity prices.

A critical point is certainly the mentioned photovoltaic system for heat generation in this case. The costs between solar thermal and photovoltaic cannot be directly compared here, since normally the electrical energy from a photovoltaic system would be used, for example, to operate a heat pump. Converting electrical energy 1:1 into heat (e.g. via a heating resistor) neither makes energetic nor economic sense, as the specific costs exceed those of alternative heat supply concepts. However, with a possible high self-consumption of an additional photovoltaic system, it can of course become attractive for power supply in your own home.

Best regards, Erik

, an air-to-water heat pump is not allowed to be installed? Are you sure?

The ventilation system with heat recovery will cost around 10 to 12,000 euros (as a guideline).

He does not want an air-water heat pump. Edit: No water or ground source heat pumps are allowed to be built.

I don't think the approach is wrong either and have been thinking about exactly that. Gas condensing boiler for heating and heat pump for hot water and independently photovoltaic on the roof. Has no one implemented this yet? For us, the alternative would be: air-to-water heat pump and photovoltaic In both cases with central controlled residential ventilation. Geothermal energy is prohibited.

Where did someone suggest combining gas and heat pump? Or am I blind? It doesn't seem smart to me either to install two (expensive) heat generators, especially when the focus is anyway on gas, the hot water from it is almost a side product. What is a heat pump supposed to contribute additionally? Or are you throwing heat pump and ventilation system with heat recovery together right now?