Wasn't a ground source heat pump outrageously expensive for you?
No, I would save about €2,500 with gas/solar compared to a ground source heat pump. With the tube collectors it might even be an extra cost with gas/solar - I need to inquire about the price difference.
And why aren’t the flat ones an option? Just let them install those and then the issue is settled.
I have to ask if the company is willing to carry it out that way. And whether it's even allowed. They have now shown me these two options; I can clarify more only on Monday. The question is whether the tubes are so much more expensive that the lower price for inefficient flat roof collectors “pays off” or whether despite the extra cost a more reasonable cost/benefit ratio results from using the tube collectors. Unfortunately, I only received the two pictures. I would have to request calculations. Since that is always very slow, I would have to specify exactly which data I need.
Because an air-to-water heat pump is about €10,000 - 15,000 cheaper depending on location and you would only recoup that with a ground source heat pump after many decades (if at all!).
I absolutely do not want such an outdoor unit and if a heat pump, then only a ground source heat pump with the most efficient coefficient of performance.
A ground source heat pump including drilling is about €2,000 more expensive than an air-to-water heat pump. I really don’t need a second to think about that if these are the only two options.
What annoys me about heat pump stuff is simply that I estimate that it is often nicely calculated. I see higher maintenance costs here than with established gas boilers, where you have a heating technician on every corner. If we had taken the offered Waterkotte AI1 Geo, then you would also have to have one of the rare Waterkotte service partners, who isn’t really around the corner and who, in addition to the expensive hourly rates (due to less competition than with a classic heating technician), still adds hefty travel surcharges. If such a heat pump is perfectly adjusted, it might pay off and if you have few technician visits due to the solidity of the whole system. But with the slightest irregularities, my assessment is that due to the ancillary costs (regardless of the often unattainable electricity consumption indicated) you will be more expensive than with gas/solar.
We currently have a Nibe system in the rental property. It is supposed to be serviced once a year or every two years (I don’t know exactly because I don’t have the contract). There is a maintenance contract. There are two heat pumps in the house. This costs the landlord about €500 every time with everything included and the guy is there less than 30 minutes. When someone comes for the oil heating at my parents’, it costs €120 for a normal maintenance. At first, there was huge drama about the inefficiency of the whole system. Then it was pushed back and forth. The Nibe guy said the ventilation system's dampers were not properly adjusted; the ventilation installer said he was not given any information about that. Then the Nibe guy measured the entire ventilation system, adjusted the dampers correctly and billed the landlord a hefty invoice.
Pellets are not an option. Now it’s basically just about the choice of solar collectors. But we won’t be able to finalize it here without knowing the price difference and whether they would be willing to install the flat collectors in a functionally reduced way on the roof. For the tube collectors, it looks like fewer m² need to be installed. That will certainly somewhat relativize the extra cost.