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

Hello everyone,

I am in the final stages of house planning.

Here are the key data of the building:

- Location: Low mountain range
- House: Timber frame
KFW 55 --> Qp = 40.9 kWh/m² and H´T= 0.259 W/(m²K)
Thermal bridge loss = 0.038 W/(m²K)
Usable roof area: approx. 40 m2
- Pitch: 35 degrees gable roof
- Orientation: Southeast
- Roof window: 1 centered
- Heated building volume: 497.9 m³
- Usable building area: 159.3 m³

As a heating system, an air-to-water heat pump and a central controlled residential ventilation system with heat recovery are planned.

Currently, I am concerned with the topic of a potential photovoltaic system.

Apart from ecological considerations and purely from an economic point of view, is a photovoltaic system worthwhile in the long term? Is it sensible to try to reduce heating and electricity costs with it?

I think the time until the system pays off will be very long; furthermore, the system delivers the least in winter when the heat pump needs the most energy.

What do you think about such a system? Would you build one?

Thank you very much

Regards

Steffen

Without actually knowing the details now.

If you have the money lying around anyway and don’t expect a return, such an investment pays off cautiously calculated in about 10-12 years, if you want a return or at least have to take out a loan for it, you should be done at the latest after 15-17 years. I have not assumed any price increases here, but rather a constant price level.

Depending on orientation and individual circumstances, the situation shifts by a year or two.

You can forget about storage for now unless it is virtually given away through subsidies. Otherwise, it becomes too expensive. Or you calculate with rising electricity prices, then it can also work in 20 years, otherwise rather... even longer or not at all.

By the way, we have a photovoltaic system.

So the money isn't just lying around. An investment could barely fit into the budget. But then nothing must become more expensive either.

I also wonder if it is really a meaningful and worthwhile investment in terms of cost savings. If not much comes out of it annually, I would rather leave it alone.

So the money is not just lying around. An investment might just barely fit into the budget. But then nothing is allowed to become more expensive.

In that case, the photovoltaic system should be acquired with 100% external financing. Since you operate a business with the photovoltaic system, the loan interest can be deducted from the income. It would then be unwise to pay for the photovoltaic system yourself and have the last invoice for the house through the loan.

As for the "profit," of course that depends on many factors. Roof size, slope, location, self-consumption "during the day."

The aforementioned payback period gives an approximate outlook. After that, you can sell the electricity for a few years thanks to the Renewable Energy Act or just use it yourself "for free."

The profit, as so often, lies in purchasing.

Every Tom, Dick, and Harry offers photovoltaic systems just as an add-on. The prices are correspondingly abysmal.
For us, prices ranged from €2000/kWp (heating engineer with a "complete solution from Vaillant") to €1700/kWp from the electrician, €1600/kWp (solar technician; high-quality components but still too expensive) and now to €1150/kWp (regional solar technician with solid components). All prices all-inclusive, net, without storage (of course).

Anyone who wants it to be financially worthwhile must buy cheaply and especially do without a storage solution, unless it could be worthwhile due to "already there" costs and subsidies. Then, in my opinion, a 5% return is quite possible.