Common questions about solar, storage and heat.

That depends less on the location than on the roof and your consumption: orientation, tilt, shading and how much of the generated power you can use yourself. West-east roofs are as standard today as south-facing ones, because they spread generation across the day; even north-facing roofs deliver solid yields with modern modules. We assess this on site and tell you honestly if a system does not pay off.

Mainly in Gechingen, the Calw area and Pforzheim; we have already completed projects in most towns within 25 kilometres, such as Althengstett, Weil der Stadt, Böblingen, Sindelfingen, Herrenberg and Nagold. Our regular service area is around 50 kilometres, reaching the greater Stuttgart area, and larger projects are possible across Germany by arrangement.

A battery shifts the midday power into the evening and night. It pays off especially when little is consumed during the day and a lot in the evening, for example cooking, laundry or charging an electric car. Correct sizing is what matters: an oversized battery costs money without adding value.

Almost always. The deciding factors are the required flow temperature, the existing radiators and the state of the building envelope. Large radiators or underfloor heating help but are not a requirement. We run the numbers before the decision instead of promising across the board.

Yes. With surplus charging, the car prefers to charge whenever the system produces more than the house is using. For that, wallbox, inverter and distribution board have to be properly matched, and exactly that integration is our trade.

It converts the direct current from the modules into household-grade alternating current. It is also the point where the system is monitored: yields, faults and the communication with battery and grid all come together here.

For us, registration with the grid operator is part of the installation. Bergkonn Electronics is registered as a qualified contractor with Netze BW and may register and commission systems there.

In four steps: In the initial consultation we clarify what makes technical sense. During the on-site survey we look at everything that matters for your project, from the building and the electrics to the rooms. Sizing and quotation are then prepared in-house, transparent and traceable. Finally come mounting, commissioning and instruction, and we remain your point of contact.

Generation, storage, heat and distribution interlock inside a building. Splitting the trades means managing interfaces and searching for the responsible party when something fails. With us, one company is responsible for the interplay.

The federal government supports switching to a heat pump through KfW (programme 458, heating subsidy for private individuals): a base subsidy of 30 percent of eligible costs, plus combinable bonuses, for example when replacing an old oil, gas or storage heater, and tiered by household income. Combined funding for owner-occupiers is generally capped at 70 percent, with up to 80 percent possible for lower incomes; eligible costs are capped at 28,000 euros for the first residential unit. As of September 2026; the rates were last adjusted in July 2026 and may change again. We check which bonuses actually apply to your building and advise you on the application.

Yes. The zero VAT rate under Section 12 (3) of the German VAT Act (UStG) remains in force with no expiry date: supply and installation of photovoltaic systems and battery storage on or near residential buildings can be billed at 0 percent VAT, generally up to an installed gross capacity of 30 kilowatts peak per the market master data register. As of September 2026. We check whether your specific project meets the requirements; for the tax assessment of your individual case we also recommend consulting your tax adviser.

Usually yes. By law, the fixed EEG feed-in tariff falls by 1 percent every six months and stood, as of September 2026, at 7.70 cents per kilowatt-hour for partial feed-in and 12.22 cents for full feed-in, for rooftop systems up to 10 kilowatts peak. What makes a system pay off today is mainly self-consumption, because power you generate yourself replaces significantly more expensive grid electricity, and that effect grows as the feed-in tariff falls. We work out exactly how this adds up for your roof and your consumption in a personal consultation.

Yes, the KfW loan 270 (Renewable Energies Standard) offers low-interest financing for photovoltaics, storage or a heat pump, covering up to 100 percent of investment costs, for businesses and for private individuals who feed part of their power or heat into the grid. It is a loan, not a grant; the actual interest rate depends on creditworthiness and collateral. As of September 2026. We are happy to discuss whether the loan makes sense for your project or whether self-financing thanks to the zero VAT rate is the better route.