Energy Renovation and Selling Property in Luxembourg in 2026

In 2026, energy performance has become a decisive criterion for Luxembourg buyers. An energy certificate (CPE, Luxembourg's mandatory energy performance certificate) of class A or B can significantly increase your property's value, while a class G, H or I rating can considerably slow down the sale.

Impact of the energy class on the sale price

According to Luxembourg market data for 2026, the price gap between energy classes is significant:

• Class A-B: average price 15-20% higher than class D
• Class C-D: the market benchmark
• Class E-F: 5-10% discount
• Class G-I: 15-25% discount, or even more in some municipalities

For a €500,000 apartment in class D, moving up to class B could mean an extra €75,000 to €100,000 on the sale price.

The most profitable renovation works

Thermal insulation

Insulation is the best investment in terms of cost-effectiveness:

• Roof insulation: €15,000 - €30,000 (highest ROI)
• External wall insulation: €20,000 - €50,000
• Floor insulation: €5,000 - €15,000

Window replacement

Switching to triple glazing costs between €800 and €1,500 per window, with an immediate visual impact for prospective buyers.

Heating system

Replacing an oil boiler with a heat pump:

• Air-to-water heat pump: €15,000 - €25,000
• Geothermal heat pump: €25,000 - €45,000

PRIMe House financial aid

Luxembourg offers generous subsidies for energy renovations through the PRIMe House programme:

• Thermal insulation: up to €50/m²
• High-performance windows: up to €150/m²
• Heat pump: up to €8,000
• Photovoltaic installation: guaranteed feed-in tariff

These subsidies can cover 30 to 50% of the cost of the works, making renovation highly profitable before a sale.

Renovate or sell as is?

The decision depends on several factors:

• Renovate if: the energy class is G-I, the works are straightforward (insulation, windows), and the local market places a strong premium on energy performance
• Sell as is if: the rating is already D-E, the necessary works are structural and expensive, or you need to sell quickly

To add value to your property without major works, also consider home staging.

FAQ

Is the energy certificate mandatory to sell in Luxembourg?

Yes, the CPE is mandatory for every property sale in Luxembourg. It must be available as soon as the property goes on the market and mentioned in the listings.

How long does an energy renovation take?

Allow 2 to 6 months depending on the scale of the works. External insulation takes 4 to 8 weeks, window replacement 1 to 2 weeks, and installing a heat pump 1 to 2 weeks.

Are energy renovations deductible from capital gains?

Yes, renovation works carried out in the last 5 years can be deducted when calculating the taxable capital gain, thereby reducing the tax due.