Gas or heat pump? Experiences / Feedback

Wait here once more for professional feedback from the expert.

Thank you and yes, I will do that. Nevertheless, we are very grateful for your help, because it allows us to view the topic repeatedly from a different perspective.

A compact unit is available from 3,000€, installation can be done by any heating engineer without special knowledge. Maintenance costs are the same or lower than with split systems. In case of major damage, replacement is cheaper. Split systems require special knowledge, and may have more integrated technology such as the hot water storage tank. There is no argument in favor of split systems.

I would only consider purely indoor installation if geothermal energy is used as the source.

Take a look at the "simple" hydraulics on the mentioned page, which should be the target for all compact units. If you somehow reach a heating load of 5kW, then take the device suggested on the page; it won’t get cheaper and better would be difficult.

Then only the basic question remains whether you should give the air-to-water heat pump a chance or trust the good old gas.

I would, as already mentioned, depend on the offers. If you only get defensive offers for the air-to-water heat pump, it makes no sense to take it. Numbers thrown off the cuff: With 210m² you have a supply temperature of €800 heating costs with gas+solar, with air-to-water heat pump and 10kW photovoltaic (considered as a unit) it's about €0. Then you just have to consider what the additional costs are worth to you compared to the savings. With the awareness that no one knows how electricity and gas prices will develop. Fairly, one must also say that with gas and photovoltaics (considered as a unit) you would only have a few euros in heating costs left.

I would, as already mentioned, depend on the offers. If you only get rejection offers for the air-to-water heat pump, it makes no sense to take it. Some rough numbers thrown together: For 210m² you have a flow temperature heating cost of €800 with gas+solar, with air-to-water heat pump and 10kW photovoltaic (considered as one unit) it is about €0. Then you have to consider what the additional costs are worth to you compared to the savings. Knowing that no one knows how electricity and gas prices will develop. Fairly, one must also say that with gas and photovoltaic (considered as one unit) you would also have only a few euros of heating costs left.

Okay, thanks. I hope we get the offers today. I will then let you know. About photovoltaic: We plan to rent/lease it. Are there any experiences or opinions on that? If you pay €90 monthly for it and then feed electricity in return, that should actually be worth it, since the air-to-water heat pump can also be operated with the self-generated electricity? Or is that too simple a naive calculation?

You can calculate it yourself. €90 is €22k in 20 years. For what size of investment? The usual 10 kWp typically costs around €12k on average, which you actually don't reach when considering interest.

You can calculate it yourself. €90 are €22k in 20 years. For what size of installation? The usual 10 kWp rather costs an average of €12k, you actually don't get there even when considering interest.

Okay yes, the €90 were possibly an exaggerated value from me. Before you calculate too optimistically and it fails in the end. Because paying €12k at once is unfortunately not possible for us.