Air heat pump or use gas and solar?

Gas costs are indicated per kWh at 7 cents - energy costs are stated as 833 € --> 11100 kWh heat; electricity costs are indicated at 19 cents (cheap, by the way) and energy costs at 539 € --> 2836 kWh electricity --> 11100 / 2836 --> 3.9... at least that is what the heating engineer assumes.

We have a gas heating system with 10sqm solar support.
Heated living area: 180sqm
Annual gas bill: 650,-

When calculating costs, be sure to include the noise level of the air heat pumps. In our neighborhood, someone installed an air heat pump. The thing can get very, very loud. There is quite a bit of stress with the neighbors. I wouldn't want that.

Here are several air heat pumps nearby and actually all are quiet even in the deep winter.

The one from my brother-in-law can only be heard at the highest level if you stand next to the air intake. At a distance of 10m, you can't hear anything anymore. It might be due to the device, ask the stressed neighbor for the model and write it here.

An interesting thread that is currently relevant for us as well. Here is our new construction project.



Contrary to our desired expectation, a geothermal heat pump with a deep probe is not possible.

For us, the following options are up for consideration (each with information on additional costs compared to the initially planned Waterkotte AI 1 Geo without costs for the deep drilling, which the general contractor initially assumed at €15,000, but which is not feasible):

First of all, it should be mentioned that the house will have a controlled residential ventilation Vaillant Reco Vair with heat recovery.

1) Gas and Solar:
Viessmann Vitodens 200-W with Vitosol 200F and 400l water storage Vitocell 100B
---> €4,899 additional cost plus gas connection costs approx. €2,000 to €2,500

2) Air Heat Pump:
Waterkotte Eco Touch DA Air 5018.5 Ai with 390-liter Waterkotte EcoStock storage
---> €9,487 additional cost, thus effectively €2,100 to €2,600 more expensive than the gas/solar solution

3) Geothermal with surface collectors:
Probably the least attractive option. The Waterkotte AI1 Geo would remain. Additionally, approx. €10,000 for surface collectors and according to the general contractor’s estimate, €6,000 to €8,000 (!!) for earthworks

Based on my current—unfortunately still subjective—assessment, I am rather in favor of gas + solar or just gas if one can get through with the exceptional conditions possible here.

I have spoken with several installers who are of the opinion that, given the underlying project and a calculated heating load of 7,548 W, an air heat pump is not a reasonable alternative to the gas/solar combination. Can this be said so categorically? The whole thing will change slightly because we had to lower the building height somewhat to obtain the building permit. It will be recalculated then but will certainly not completely overturn the decision basis as such. It will be about 41m³ less enclosed space.

I have a detailed heating load calculation. Which values from this might still be relevant for an evaluation of the question?

Our general contractor had the heating load calculation done by this company here.

Is it worth going further in depth here, commissioning calculations and weighing options? Or is gas or gas/solar really the goal-oriented solution here? I do not find the idea unsympathetic. But that is rather subjective. I consider gas boilers to be the more mature technology and believe that electricity prices will rise more strongly than gas prices. If we ever get a situation like in Denmark, where no new buildings with oil and gas heating are allowed at all, there could even possibly be a massive oversupply of gas. Of course, these are all speculations. I certainly do not believe that gas will become significantly more expensive than electricity.

Then just hurry up and have the [Energieberater] check whether you need the solar thermal system or not.