Is solar worth it for your home in Luxembourg?

What the calculator does

Three tools, each with its own inputs. You can stop after the first one.

1. 1. Annual yield and savings

   Choose a canton, the orientation and tilt of the roof, a system size and your annual consumption, with or without a battery. The tool returns the expected production in kWh per year, from the PVGIS solar yield published by the European Commission's Joint Research Centre, together with the share you would consume yourself and the yearly saving.

2. 2. Return on investment over 25 years

   Compares the two public support schemes a household can choose from. Option A is the Klimabonus 2026 grant: P × (1,155 − 33 × P) euros for a system of P kWp below 15 kWp, 10,000 euros from 15 kWp, plus up to 2,250 euros for a battery; the surplus is then sold at market value. Option B is the guaranteed feed-in tariff for 15 years, 165 × 0.97^(n − 2019) euros per MWh for a first injection in year n, up to 10 kW, which is about 129 euros per MWh for 2027. The tool gives the payback year and the net gain over 25 years for each option.

3. 3. Heat pump heating

   Estimates how much of a heat pump's electricity a solar system covers over a year, and how much still has to be bought, from the heated surface and the insulation level of the house.

Three worked examples

Computed by the calculator on 2 November 2026 with its default assumptions: due south, 35° tilt, canton of Luxembourg, 1,800 euros per kWp installed, avoided kWh valued at 0.20 euros, surplus at 0.05 euros, first injection in 2027. The first scenario changes the orientation to south-east, the third adds a 7 kWh battery.

Option A: Klimabonus grant, surplus sold at market value. Option B: guaranteed feed-in tariff for 15 years, no grant. With these assumptions the grant pays back faster in all three cases; the gap narrows when consumption is high relative to production.

What a kWh you no longer buy is worth

The saving per kWh is the variable part of the electricity bill, not the bill divided by the number of kWh. For a household in Luxembourg it is about 0.16 euros from August to December 2026 (State contribution under the law of 22 July 2026) and about 0.20 euros at the January to July 2026 rate, rather than the 25 cents a quick division suggests. The calculator uses 0.20 euros by default and lets you change it.