Photovoltaic system in new construction: Would you install one? Any experiences?

Theoretically, with 300-watt modules, you can fit 7.27 kWp on your roof; in practice, it will be less because the modules have specific dimensions, you may have a dormer, a satellite dish, possibly a “Schneerutschschutz”, etc. Thus, you will have an estimated 7-6.5 kWp left. Depending on the orientation of the roof, you will then get 6500-4500 kWh per year from the roof. Of that, you will consume 3500 kWh. The rest will be fed into the grid. The photovoltaic system will hardly provide anything for the air-water heat pump from early November to the end of February anyway, since hardly anything comes from the roof during that time.

We have decided to install a photovoltaic system. For aesthetic and technical reasons, we chose an almost invisible solution with solar tiles from Autarq. The focus is on production for our own use, fire-extinguishable low-voltage technology on the roof, and independence in the event of a power outage. Overall, for environmental protection reasons, we aim to produce more than we consume annually. In the summer months, we feed surpluses into the grid; in the winter, we purchase a little additional power.

Putting ecological considerations aside and looking purely from an economic perspective, is a photovoltaic system worthwhile in the long term?

Actually not, because modules lose performance, inverters might break down eventually, and batteries don’t last forever either and are expensive. If you take advantage of all tax tricks (definitely take out a loan) and are lucky with the reliability of the components and the end customer prices for electricity continue to rise significantly (including all taxes, fees, surcharges, etc...) you might break even. But a good feeling is worth something too and: What kind of car do you drive? Many spend a lot of money on unnecessary driving dynamics/performance/elegance without even thinking about it. A 911 never pays off financially; you just have more fun in life every now and then. For example, I spent 17 K on a 6.2 kWp system with a 6.3 kW battery, have had a huge joy from it for 2 weeks now, really, but I will never see that money again. Hobbies always cost...

Here again for illustration: This system has been in operation for 10 days, but we are not living in it yet. The low consumption is only from the craftsmen's devices and machines. So far, the system has "earned" about €2.30 per day through feeding in, you can calculate it yourself...

We have decided to install a photovoltaic system. For aesthetic and technical reasons, we opted for an almost invisible solution with solar tiles from Autarq. The focus is on production for our own use, fire-extinguishable low-voltage technology on the roof, and independence in case of a power outage. Overall, for environmental reasons, we want to produce more in a year than we consume. In the summer months, we feed in surpluses; in winter, we buy a bit additional.

Can you tell us something about the costs?

Unfortunately, I cannot specify the exact amount (I promised our supplier). I estimate that a 10 kWp photovoltaic system equipped with similar technology, using the usual panels and typical mounting, is available for 25-30% less. Exact information is available from Autarq.