Construction costs are currently skyrocketing

I find it very uncomfortable to walk on 15°C cold floors in the middle of summer because the house is cooled above it.

Something from someone with experience …. 15 degrees is not allowed by the heat pump at all. The lowest value is (with our Vaillant) 16 degrees, but even that is not set. 18 degrees in midsummer at peak temperatures. Usually, it runs at 19 degrees for us. And it is wonderful to have a cool floor, although parquet of course doesn’t feel as cool as tiles. In the bathroom, the volume flow is reduced by about 50%, otherwise unchanged. Heat pump with cooling function was standard with our provider. For operation, the brine pump and underfloor heating pump run. Still original from 2008 and therefore no high-efficiency pumps. In total about 190 W, which costs approximately €1 per day. In operation for about 8 weeks with a short interruption.

Well, my system with 10kwp was still quite profitable in January, if I read this correctly. My system generated 383.4kwh, of which I consumed 275.1kwh myself and only fed 108.3kwh into the grid. For that, I had a total consumption of 1,243.6kwh for household electricity, heating, and car charging. My only problem so far has been that I couldn't break down how much electricity I needed for household electricity, heat pump, and car respectively. Meanwhile, I can at least see through the Wallbox how much goes to the car and the heat pump got an intermediate meter last month. I'm curious to see what comes out of it.

Thank you for the tip. It tells me that I have a return of over 37% and a payback period of the investment after 4 years :)

Possibly electricity costs given in the wrong unit? Or: Self-consumption means how much of your yield you consume yourself as a percentage. Also a pitfall.

Self-consumption can usually be estimated at 25-30%. In my offer, 1 kWp was about €2,100 net (without storage). Due to east/west orientation, PVGIS suggests approximately 770 kWh per year per installed kWp. The solar installer calculated a smooth 980. This results in a payback period of about 20 years... if no inverter breaks down outside the warranty period.

In my offer, 1 kWp was about €2,100 net (without storage).

A year ago there was a transposition of the first two digits. Amortization much faster.

With what self-consumption (cents for saved electricity costs) was calculated? Now that I see that electricity is sometimes offered for over 60 cents (EON, for example), you can really save/earn.

according to PVGIS, about 770 kWh p.a. per installed kWp are possible. The solar installer calculated with a smooth 980.

My previous systems have each exceeded the calculations of my solar installer. My current WSW system generates 950 kWh per kWp (and the next one a bit more, when the 70% throttling is lifted) – matches your solar installer’s statement.

Self-consumption 30%, is PVGIS faulty (?), I also thought that was a transposition error! The abolition of the 70% rule would probably be the right step, but how often does a photovoltaic system achieve yields over 70% of the installed kWp? I have no experience there. For me, the orientation would be 40% east and 60% west, unshaded. Btt… with the current prices, one should definitely get some offers or maybe wait for more efficient modules. I think the development is currently being strongly driven.