Is it possible to sell self-generated electricity to tenants of a multi-family building?

Why is the insulation not included with new gas boilers?

It is about the insulation of the exterior walls. I wanted to have this measure carried out anyway. After all, it is still the construction standard from 1994.

Then, for comparison purposes, these insulation costs must also be added to Variant A with the gas boilers or deducted from Variant B and C. Otherwise, you are comparing apples and oranges.

That is nonsense. The complete renovation cannot be passed on to the tenants. And if tenants could really buy electricity for 20 cents (,without basic fee), that would be a real bargain. Where else can you get electricity cheaper?

A: insulation only (10,000) and renewal of the gas boilers when they break down. Out of 4 units from 1994, 3 are still running. 1 was renewed last year. B: including insulation and heat pump minus subsidy: 75,000,--

I still don’t understand ... in option B the insulation should only be 10,000 euros, and then the heat pump minus subsidy should cost 65,000 euros? Is it made of gold? Or what other work is supposed to be covered by that?

I still don't understand ... in variant B the insulation should only be 10,000 euros, and then the heat pump after deduction of the subsidy is supposed to cost 65,000 euros? Is it made of gold? Or which other work is supposed to be covered there?

Since I don't know the circumstances of the house, I can only guess - but based on my assumption, 65k€ for the heat pump with everything and already after subsidy is not a problem.

Consider: You have to completely rework the entire heating concept! The thing currently has four completely autonomous apartments, each with its own heating and water supply; all of that has to be newly installed, connected, and above all centrally and cleanly planned.

That's something completely different from replacing a single gas heating system for all 4 apartments... and the stress during that time with the tenants... I'd go crazy...