What to consider for a PV system? The Swiss guide before your first quote

The most common planning mistake is to size the system by the available roof area instead of by electricity use. The sensible order is the other way round: first clarify your annual consumption and daily profile, then derive the size. As a rough guide, in Switzerland 1 kWp of capacity yields around 900 to 1,000 kWh per year; a four-person household using roughly 4,500 to 5,000 kWh therefore lands at about 5 to 6 kWp for household electricity alone. Even so, it usually pays to cover as much of the roof as possible – the extra cost per additional module is small, and consumption rises with a heat pump and an electric car anyway.

Every kilowatt-hour you use yourself is worth considerably more than one you feed into the grid. Electricity from the grid costs roughly 30 centimes per kWh, while the feed-in payment for exported electricity is often only about a third of that, depending on the grid operator (as of 2026, varying widely – pvtarif.ch shows your local tariff). The biggest economic lever is therefore not the feed-in tariff but a high level of self-consumption: loads such as the water heater, heat pump, dishwasher or charging the electric car can be shifted deliberately into sunny hours. A battery can raise self-consumption further – but whether it pays off is a separate question.

Before any talk of modules, the roof decides. A south-facing orientation at around 30 degrees of tilt gives the highest annual yield, but east-west layouts work very well and spread production more evenly across morning and evening. The single biggest loss of yield rarely comes from a slightly unfavourable orientation, but from shading by trees, chimneys, roof structures or neighbouring buildings. Roof condition and structural load matter just as much: if a roof renovation is due in the next few years, it belongs before the installation. A first, free estimate of the potential is provided by the federal Sonnendach.ch tool – but it does not replace an on-site roof survey.

With components, it is not the brochure that counts but lifetime and warranty. Modules typically last 25 to 30 years; the inverter, the heart of the system, usually has to be replaced after 10 to 15 years – this replacement belongs in any honest calculation. Look for separate product and performance warranties on the modules, a warranty covering installation and roof watertightness, and an inverter with headroom for a later expansion. Where there is partial shading, power optimisers or micro-inverters are worthwhile. In Switzerland, the hail resistance of the modules is also relevant – including with a view to building insurance.

Incentives are not a side issue but part of the economics – and in Switzerland they come in several layers. Nationally there is the one-time remuneration handled by Pronovo, which covers part of the investment cost. On top of that come cantonal and municipal programmes whose level depends on where you live; energiefranken.ch offers an overview by postcode. Thirdly, on an existing building a system is tax-deductible as property maintenance in most cantons. All of these amounts and rules change regularly (as of 2026); concrete figures belong in the property-specific quote, not in a blanket rule of thumb. Because incentives influence the sequence and the deadlines, you should check them early and for your canton.

EnergieSchweiz, the federal programme, explicitly recommends obtaining and comparing several quotes before deciding – a good rule of thumb is three. That is exactly what we advise too. The lowest price is not automatically the best offer: quotes are often hard to compare because they contain different assumptions, components and services. Gather several impressions – and make our free orientation one of them. A quote that discloses its assumptions and calculates over the full lifetime will hold up to comparison. Do not jump at the first offer – and scrutinise ours too, rather than simply taking it.