It would now be correct to compare his system with photovoltaic to a heat pump with photovoltaic and to include the additional interest costs of the higher investment.
In addition, there is the lifetime of the systems and the replacement costs after time x.
These are not many numbers now.
I would also take them as continuous text if it does not end in a wall of text.
Here is the calculation from the previous example again with interest.
Of course, as mentioned before, the electricity price increase must also be taken into account!
Let's calculate the whole thing over 18 years because the managing director always wants the VDI 2067, and it states this as the "lifetime" for a heat pump:
150m² with 40kWh/m²a -> 6000kWh/a heating energy demand
10kWp photovoltaic + 5kWh storage -> ~15kWh/day in Nov, Dec, Jan, Feb. With 10kWh for household electricity including hot water, 5kWh/day remain for heating.
I leave out hot water each time because both systems can provide it with a COP of 4, thus making no difference; the electricity for hot water is included in household electricity.
Electricity purchase price 35ct/kWh
Feed-in tariff price: 8.2ct/kWh
Interest 3.5% (current interest for 10 years fixed)
Electricity price increase 6% (average of the last 20 years)
Vestaxx:
Surcharge on normal windows: 10,000€
Purchase and installation BWWP: 5,000€
Interest for the purchase over 18 years: 5,239€
4 [months] * 30 [days] * 5 [kWh/day] = 600 [kWh] from photovoltaic electricity
Remaining 5400kWh as purchase
Totals to (average, due to rising electricity prices) 5400*(35+35*1.06^18)/2 + 600*8.2 = 3,691€/year
after 18 years that results in: 86,686€
Heat pump:
Hydraulics: 80€/m²*150m = 12,000€
Purchase air-water heat pump monoblock and installation: 20,000€
Interest for the purchase over 18 years: 11,176€
Electricity demand: 6000/4=1500kWh
Remaining 900 to purchase
Totals to (average, due to rising electricity prices) 900*(35+35*1.06^18)/2 + 600*8.2 = 656€/year
after 18 years that results in: 54,988€
This results in additional costs for Vestaxx in this example of 31,697€ compared to the heat pump.