Frequently Asked Questions

Depending on system size, self-consumption rate and electricity price, residential systems typically pay back in 5–8 years and commercial systems in 3–5 years. With a service life of 25–30 years, the remaining years are practically free electricity.

No. South gives the highest total yield, but east-west roofs produce only about 10–15 % less and spread production more evenly over the day, which often increases self-consumption. Only north-facing pitched roofs are usually unsuitable.

On cloudy days the system still produces, just less. At night and whenever solar is not enough, grid-connected homes automatically draw electricity from the grid — or from the battery if one is installed. You never need to switch anything manually.

Not when installed correctly. On tiled roofs we use roof hooks that sit under the tiles without drilling through them; on metal roofs we use sealed clamps or rail fixings with EPDM gaskets; flat roofs can be ballasted with no penetrations. We give a workmanship warranty on all roof work.

Modules usually come with a 12–15-year product warranty and a 25–30-year linear performance warranty; inverters with 5–10 years (extendable); LiFePO4 batteries with 10 years. In addition, we provide our own workmanship warranty on the installation.

The installation itself takes one to two days for typical 5–12 kWp systems. The whole process from site survey to grid connection usually takes three to six weeks, depending on the grid operator’s approval time.

In most locations rain keeps tilted modules reasonably clean, so one to two professional cleanings per year are sufficient. Near dusty roads, farmland, industry or the coast, three to four cleanings may be worthwhile. Monitoring data shows when soiling losses exceed the cost of a cleaning.

In most cases a rooftop system for self-consumption does not require a building permit, but it must be registered with and approved by the grid operator before connection. Listed buildings, protected areas and ground-mounted plants can require additional permits. We check the requirements for your site and handle the applications.