Solar panel ROI in Luxembourg: detailed calculation
For a well-sized residential installation, the payback period observed in Luxembourg in 2026 is 7 to 11 years, after the Klimabonus grant — over a 25 to 30 year lifespan.Here is the detailed calculation and how it compares with other forms of savings.
Worked example for a 5 kWp installation
| Price before grant | €11,125 |
| Estimated Klimabonus 2026 grant | −€4,950 |
| Net cost after grant | €6,175 |
| Estimated annual production | 4,750 kWh |
| Self-consumed (35%) at 25 cents/kWh saved | ≈ €416/yr |
| Surplus sold at 7 cents/kWh | ≈ €216/yr |
| Total annual savings | ≈ €632/yr |
| Payback period | ≈ 9.8 years |
Indicative example based on market ranges and the Klimabonus 2026 scale detailed on ourprices andsubsidies pages. Your actual self-consumption rate depends heavily on your consumption profile — see ourdedicated guide and thesimulator for a personalised estimate.
Solar vs a savings account
A standard Luxembourg savings account yields around 1.5 to 3% a year. A solar installation paid back in 7 to 11 years, with a 25-year panel performance warranty (see ourmaintenance and lifespan guide), generates a markedly higher implicit return over its full lifespan — at the cost of less liquid capital than a bank deposit.
Tenants, landlords and co-owned buildings
The Klimabonus mainly targets owner-occupiers. Landlords and co-ownership associations may be eligible under specific conditions, to check case by case on Guichet.lu. For a co-owned building, a decision from the general assembly is generally needed before any quote — see ourpages by municipality for concrete examples by local building type.
Impact on your carbon footprint
Self-consumed electricity replaces a share of consumption that would otherwise be covered by the national electricity mix, which relies heavily on imports. The exact size of the reduction varies with the imported mix at the time of consumption, but the direction stays constant: the more you self-consume, the less your household depends on the grid.
Free simulation based on your roof and your actual consumption.
Frequently asked questions about solar panel ROI
How do you calculate the payback period of a solar installation?
Payback period (in years) = net cost after Klimabonus ÷ annual savings. Annual savings combine self-consumed electricity (20-30 cents/kWh saved) and surplus sold (4-10 cents/kWh). For a typical 5 kWp installation, this works out to roughly 8 to 10 years.
Is solar more profitable than a savings account?
A standard Luxembourg savings account yields around 1.5 to 3% a year. A well-sized solar installation, paid back in 7 to 11 years, generates an implicit return of roughly 9 to 14% a year over its 25-30 year lifespan (performance warranty) — clearly higher, at the cost of lower liquidity than a savings account.
Can a landlord benefit from the Klimabonus?
The Klimabonus 2026 mainly targets owner-occupiers, but certain rental setups may be eligible depending on the arrangement — check case by case on Guichet.lu before committing, as the exact eligibility conditions depend on the property status.
What about a co-owned apartment building?
Installation generally requires a decision from the co-owners' general assembly before any quote, and the minimum required power per unit is 1.5 kWp in that case. See our subsidies page for the full applicable scale.
Does a solar installation really reduce a household's carbon footprint?
Yes: self-consumed electricity replaces a share of consumption that would otherwise be covered by the national electricity mix, which relies heavily on imports. The exact size of the reduction depends on the imported mix at the time of consumption, but the direction stays constant: the more you self-consume, the less your household depends on the grid.