ᐅ Photovoltaic system in a new build: Would you install one? Any experiences?

Hello everyone,

I am in the final stages of planning my house.

Here are the key details 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 (430 sq ft)
- Roof pitch: 35 degrees gable roof
- Orientation: Southeast
- Roof window: 1 centered
- Heated building volume: 497.9 m³ (17,580 cu ft)
- Usable floor area: 159.3 m² (1,714 sq ft)

The heating system will be an air-to-water heat pump and a central controlled mechanical ventilation system with heat recovery.

At the moment, I am considering the possibility of installing a photovoltaic system.

Putting ecological considerations aside and focusing purely on economic factors, is a photovoltaic system worth it in the long term? Does it make sense to try to reduce heating and electricity costs with such a system?

I think the payback time will be quite long, and it provides the least output in winter when the heat pump consumes the most energy.

What are your thoughts on installing such a system? Would you build one?

Thank you very much.

Best regards,
Steffen

Without knowing the exact details.

If you already have the money sitting around and do not expect any return on investment, such a system will pay for itself in roughly 10-12 years if estimated conservatively. If you want a return or at least need to take out a loan for it, you should be done paying it off within about 15-17 years. This calculation assumes stable prices, not factoring in any price increases.

Depending on the orientation and individual circumstances, this timeframe can shift by a year or two.

You can forget about storage unless it is virtually free due to subsidies. Otherwise, it becomes too expensive. Alternatively, if you expect rising electricity prices, it could work within 20 years; otherwise, it will take longer or may never pay off.

By the way, we have a photovoltaic system.

So, the money is not just sitting idle. A system could possibly fit into the budget, but it would have to be very tight. Nothing else is allowed to become more expensive.

I also wonder whether it is really a sensible and worthwhile investment in terms of cost savings. If the annual return is not significant, I would rather skip it.

Skyfire schrieb:
So the money isn't just sitting around. A system could barely fit into the budget. But nothing should 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 be unwise to pay for the photovoltaic system yourself and finance the final invoice for the house through a loan.

Regarding the "profit," of course, this depends on many factors. Roof size, pitch, location, and daytime self-consumption.

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

The profit often lies in the purchasing.

Almost anyone offers photovoltaic systems on the side nowadays. As a result, prices are extremely low.

For us, prices ranged from €2000 per kWp (heating specialist with a "complete solution from Vaillant") to €1700 per kWp from an electrician, €1600 per kWp (solar installer; high-quality components but still too expensive), and now €1150 per kWp (regional solar installer with solid components). All prices are all-inclusive, net, and without storage (of course).

If you want it to be financially viable, you have to buy cheaply and, above all, forego a storage solution unless it makes sense due to "already there" costs and subsidies. In that case, a 5% return is quite possible in my opinion.