Expert guide 2026
How to improve your EPC certificate?
Priority works, impact on your property value, regional grants and personalised simulation — everything you need to turn your EPC label into financial leverage.
Why improving your EPC is a profitable investment
A better EPC label means rising property value, lower bills and grants you can claim.
Property value
An A-rated property sells on average 15% higher than a D-rated one. At €300,000, that’s +€45,000 in capital gain.
Reduced bills
Moving from G to C saves €2,000 to €3,500/year on energy bills. The investment usually pays back within 5-10 years.
Grants & support
Wallonia and Brussels offer grants covering 30 to 70% of the works. A housing audit unlocks the highest amounts.
Free tip
Improve your EPC without doing any works
Your EPC certifier can only credit what they can prove. Without proof, default — often very unfavourable — values are applied. Preparing your documents can earn you a whole label!
Gather invoices for insulation, heating or glazing works — they prove actual performance to the certifier
Find specifications or technical datasheets of materials used (lambda, thickness, type of insulation)
Provide photos taken during the works showing the insulation in place, its thickness and exact location in the building
Allow destructive checks (probing a wall, opening a casing) if no documentary proof is available — replaces default values
Carry out a Blower Door (air tightness) test to prove airtightness and replace the heavily penalising default n50 value
Insulate hot water and heating pipes in unheated spaces (cellar, attic) — small investment, strong EPC impact
Install an outdoor sensor and a programmable thermostat on your boiler — credited in the EPC calculation and easy to set up
Disconnect radiators in garages and cellars to exclude them from the EPC protected volume — reduces heated surface in calculation
Provide the commissioning report of your photovoltaic installation and boiler conformity certificates
The 6 priority works to improve your EPC
Golden rule: insulate the envelope first (roof → facades → floors), then upgrade heating and hot water based on the reduced demand. The order below reflects the best EPC-impact / investment ratio.
1. Roof insulation Up to 30% savings +1 to +2 EPC labels
The roof is the largest source of heat loss (25 to 30%). Insulating attics or flat roofs with at least 20 cm of high-performance insulation (λ ≤ 0.035) is the most cost-effective and impactful action on your EPC score.
Recommended solutions:
Indicative budget
€15-50/m²
2. Facade insulation Up to 25% savings +1 to +2 EPC labels
Walls account for 20 to 25% of heat loss. External insulation (ETICS) is the most efficient solution as it eliminates thermal bridges. Cavity wall injection is often the most economical option.
Recommended solutions:
Indicative budget
€30-180/m²
3. Heating & domestic hot water Up to 25% savings +1 to +2 EPC labels
Replacing an old atmospheric boiler with a condensing boiler or a heat pump dramatically improves your EPC score. Combine with a thermodynamic or solar water heater for domestic hot water — the impact is major.
Recommended solutions:
Indicative budget
€4,000-18,000
4. Floor insulation Up to 10% savings +0.5 to +1 EPC label
Floors above a cellar or ventilated crawl space are often overlooked. Insulating from below (cellar ceiling) is the simplest and cheapest option, with excellent cost/efficiency ratio.
Recommended solutions:
Indicative budget
€20-100/m²
5. Photovoltaic panels Direct reduction of Espec +0.5 to +1 EPC label
Self-produced energy reduces the primary consumption calculated in the EPC. In Wallonia and Brussels, solar panels directly impact the final score. An investment that also pays off through self-consumption.
Recommended solutions:
Indicative budget
€5,000-12,000
6. Joinery (frames & glazing) Up to 15% savings +0.5 to +1 EPC label
Switching from single to HR++ double glazing (Ug ≤ 1.1) or triple glazing divides window heat loss by 3. Frames matter too: choose profiles with thermal break. Moderate impact on EPC score but big gain in comfort.
Recommended solutions:
Indicative budget
€500-2500/window
Fund your works with regional grants
Wallonia and Brussels offer substantial support for energy renovation.
Wallonia grants
Brussels grants
As of now, there has been no government decision regarding any new forms of financial support for renovation. As soon as we have further information, we will share it.
Frequently asked questions
How much does it cost to improve an EPC label?
Budget depends on the building’s initial state. To move from G to D, expect between €15,000 and €40,000 for insulation and heating works. Roof insulation alone (most cost-effective action) costs €2,000-5,000 for an average house. Regional grants (Wallonia, Brussels) can cover 30 to 70% of the investment.
Can you improve your EPC without major works?
Yes! Providing proof of existing insulation (invoices, photos), documenting technical specs of your glazing and boiler can already improve your score. A certifier without proof applies default materials, often unfavourable. This is exactly what we explain in our EPC visit preparation guide.
What is the return on investment of an EPC renovation?
A property rated A sells on average 15% higher than one rated D. For a €300,000 house, that’s +€45,000. In parallel, you reduce your energy bills by €1,000 to €3,000/year. The investment is generally recouped in 5 to 12 years, not counting grants.
Can regional grants be combined?
Yes, in Wallonia housing grants are stackable (insulation + heating + audit). In Brussels, Renolution grants work similarly. The amount depends on your income and the type of works. A housing audit (mandatory in Wallonia for some grants) maximises support.
How do I know which works to prioritise for my home?
Golden rule: insulate the envelope first (roof → facades → floors → glazing), then size the heating system to the reduced needs. Certinergie’s CertiBoost gives you a personalised action plan based on your actual EPC certificate data.
Ready to improve your EPC?
Start with an EPC certificate from Certinergie, add CertiBoost to simulate your works, and turn your label into value.