EPC classes and indexation: complete tableau by class
Understand EPC classes (A, B, C, D, E, F, G) and their impact on rent indexation in Wallonia, Brussels and Flanders. Complete tableau.
Brief answer
In Belgium, each EPC class (A, B, C, D, E, F, G) reflects the theoretical energy performance of the dwelling, expressed in kWh consumed per m² per year. For rent indexation, the impact varies by region: in Brussels (leases prior to 14/10/2022) and Flanders, low classes (D-G) suffer a reducing coefficient (75%, 50% or 0%). In Wallonia, classes A-C follow the standard formula, while D-G leases indexed during the 2022-2023 capping window have been recalculated since November 2023 under a special method (rebased on the capped rent).
Quick read: A = excellent / G = catastrophic. For indexation, A-B-C = full indexation everywhere, F-G = 0% in Brussels (old leases) and Flanders. Calculate the applicable coefficient for your situation via the calculator.
Reading EPC classes: physical meaning
The EPC (Energy Performance Certificate) measures the theoretical energy consumption of a dwelling, recalculated according to a standardised method. The result is expressed in kWh/m²·year and ranked on a scale from A (very efficient) to G (very energy-intensive).
| Class | Common sense | Indicative consumption |
|---|---|---|
| A++ | Near-passive (rare) | < 0 (energy production) |
| A+ | Passive house | < 15 kWh/m²·year |
| A | Very good performance | 15-45 kWh/m²·year |
| B | Good performance | 45-85 kWh/m²·year |
| C | Average performance | 85-170 kWh/m²·year |
| D | Mediocre performance | 170-255 kWh/m²·year |
| E | Low performance | 255-340 kWh/m²·year |
| F | Very low performance | 340-425 kWh/m²·year |
| G | Very poor performance | > 425 kWh/m²·year |
Note: these thresholds are indicative and vary slightly between Wallonia (Espec method), Brussels (EW method) and Flanders (E-peil method). The letter principle (A-G) is identical in the three regions, and it is on this criterion that indexation is based.
Recap tableau of indexation coefficients by class and region
This is the central tableau to know for 2026 indexation:
| EPC Class | Wallonia (2026) | Brussels (lease < 14/10/2022) | Brussels (lease ≥ 14/10/2022) | Flanders (all leases) |
|---|---|---|---|---|
| A | 100 % | 100 % | 100 % | 100 % |
| B | 100 % | 100 % | 100 % | 100 % |
| C | 100 % | 100 % | 100 % | 75 % |
| D | 100 % | 75 % | 100 % | 50 % |
| E | 100 % | 75 % | 100 % | 50 % |
| F | 100 % | 0 % | 100 % | 50 % |
| G | 100 % | 0 % | 100 % | 0 % |
Three key readings:
- Wallonia: no multiplying coefficient in 2026, but D-G leases that had an anniversary during the 2022-2023 capping window are indexed under a permanent special method (decree of 19 October 2022): the calculation is rebased on the adapted (capped) rent of that period
- Brussels old regime (before 14/10/2022): only D-E (75%) and F-G (0%) are penalised, A-B-C indexed in full
- Brussels new regime (since 14/10/2022): no EPC impact — federal standard calculation
- Flanders: strictest regime, from class C a coefficient applies (75%), and G = 0%
For regional detail, see our EPC Wallonia, EPC Brussels, and our indexation cap guide.
Worked examples by class
For an initial rent of 800 €/month indexed at 2026 (full theoretical increase ~25 €/month):
| Class | Wallonia | Bxl 2020 lease | Bxl 2024 lease | Flanders |
|---|---|---|---|---|
| A | 825 € | 825 € | 825 € | 825 € |
| B | 825 € | 825 € | 825 € | 825 € |
| C | 825 € | 825 € | 825 € | 819 € |
| D | 825 € | 819 € | 825 € | 813 € |
| E | 825 € | 819 € | 825 € | 813 € |
| F | 825 € | 800 € | 825 € | 813 € |
| G | 825 € | 800 € | 825 € | 800 € |
Reading: a G-rated dwelling in Brussels (lease prior to 2022) or in Flanders sees its rent frozen at 800 € — no indexation possible that year. The Wallonia amounts assume the standard formula: for a D-G lease that went through the 2022-2023 window, the calculation is rebased on the capped rent and ends up slightly lower.
To calculate your exact case, the calculator automatically applies the right coefficient.
Why penalise low classes?
Three converging political objectives in the Brussels and Flemish Regions:
1. Fight against « energy sieves »
F-G rated properties consume 5 to 10 times more energy than A or B class. The tenant’s heating bill can reach 250 to 400 €/month in winter, the equivalent of an annual indexation… that would go to the energy supplier rather than to the landlord.
2. Incentivise landlords to renovate
By depriving the landlord of indexation as long as the property remains poorly rated, the legislator creates a progressive shortfall. Over 10 years, accumulating unrecovered indexations, the amount can justify the investment in renovation (typically 20,000 to 50,000 € to move from G to C).
3. Prepare the progressive ban on rental
Flanders has already announced the rental ban on G-rated properties from 2028. Wallonia and Brussels are studying similar mechanisms. The indexation coefficient is an intermediate step before this outright ban.
How to move from one class to another: order of magnitude of works
Without going into technical detail, here are the main levers to improve the EPC:
| Work | Typical class gain |
|---|---|
| Roof insulation | +1 to 2 classes |
| Wall insulation | +1 class |
| Frames + double glazing | +1 class |
| Condensing boiler | +1 class |
| Photovoltaic panels | +1 class |
| Heat pump | +1 to 2 classes |
| Complete renovation (passive) | up to G → A |
For most landlords, roof insulation is the lever with the best ROI: 5,000 to 10,000 € to gain 1-2 classes, i.e. unlocking full indexation in a few years (old Brussels, Flanders).
Frequent practical cases
Case 1: I buy a G in Brussels with a 2018 lease
Situation: lease signed 2018 (old regime), class G. You cannot index (0%). What to do?
- Short term: no indexation possible, plan the works
- Medium term: insulate roof + frames to move to E (75%) or C (100%)
- Long term: monitor regional announcements on G ban
Case 2: My dwelling moves from E to C thanks to works
Situation: 2019 Brussels lease, class E (75%). You renovate and obtain a new EPC class C in April 2026. Effect: the next indexation will move from 75% to 100%. Provided that the new certificate is valid at the time of notification.
Case 3: Recent lease in Flanders, class C
Situation: Flemish lease 2024, class C → coefficient 75%. Consequence: indexation at 75% of the federal formula. If the theoretical increase is +30 €/month, you recover +22.50 €.
Case 4: Wallonia, class D to G with an anniversary in 2022-2023
Situation: Walloon lease rated EPC E, anniversary in March 2023 (during the capping window). Effect: since November 2023, indexation is rebased on the adapted (capped) rent of that period, with the health index of February 2023 as starting index (special method of the decree of 19 October 2022). An A-C lease, or a lease with no anniversary in the window, follows the federal standard formula.
How to verify the EPC class of a dwelling
Three reliable sources:
- The EPC certificate itself, mandatorily attached to the lease since 2010-2011 depending on regions
- The regional database:
- Wallonia: portal energie.wallonie.be
- Brussels: portal homegrade.brussels
- Flanders: portal energiesparen.be
- The EPC included in the rental ad (mandatory since 2018-2019 in the three regions)
For the step-by-step procedure, see our « How to find your EPC » guide.
To go further
- EPC and indexation in Brussels — coefficient detail for old leases
- EPC and indexation in Wallonia — 2022-2023 window and special method
- EPC hub (all regions) — complete comparison
- How to find the EPC — official sources
- Indexation cap — economic view of coefficients
- Calculate indexation with the right coefficient — automatically applies the EPC
- Can an indexation be refused? — EPC grounds
- Methodology — detailed legal sources
The EPC class has become, since 2022, a central parameter of the indexation calculation in Brussels, in Flanders and — for D to G leases affected by the 2022-2023 window — in Wallonia. Identifying it correctly before notifying is now as important as verifying lease registration.
Frequently asked questions
What does an EPC class A, B, C, D, E, F or G concretely mean? + −
Each class corresponds to an interval of theoretical annual energy consumption, expressed in kWh per square metre per year (kWh/m²·year). A is the best performance (very low consumption, ≤ 45 kWh/m²·year in Wallonia), G the worst (very high consumption, > 510 kWh/m²·year). Precise thresholds vary slightly between the three regions. The worse the class (G), the more the dwelling consumes and therefore the higher the energy bill for the tenant.
How do I find out the EPC class of my dwelling? + −
The EPC certificate is mandatory for any property put up for rent or sale in Belgium since 2010-2011 (depending on regions). It must be attached to the lease. If you don't have it, ask the landlord or syndic. You can also consult the regional database (CWaPE in Wallonia, IBGE-Brubanq in Brussels, VEKA in Flanders). Our EPC how-to-find guide details the step-by-step procedure.
Do all EPC classes have the same impact on indexation? + −
No. The impact depends on the region and the lease date. In Brussels (leases prior to 14/10/2022) and Flanders (all leases), low classes (D, E, F, G) suffer a reducing coefficient (75%, 50% or 0%). In Wallonia, leases rated EPC D to G that had an anniversary during the 2022-2023 capping window have followed, since 1 November 2023, a permanent special calculation method (rebased on the capped rent); classes A to C and more recent leases follow the federal standard formula. The most penalising EPC class is G: 0% indexation in Brussels (old leases) and Flanders.
If my dwelling is rated G, can the landlord refuse to do the works? + −
The landlord is not legally obliged to renovate, but already suffers an indirect penalty via the impossibility of indexing (Brussels pre-2022 and Flanders). In the longer term, several regions have announced rental bans for G then F classes. Flanders will ban renting G properties from 2028. This is a strong incentive to renovate, even if no direct obligation weighs on the landlord in 2026.
Can the EPC evolve during the lease? + −
Yes, following energy renovation works (insulation, frames, boiler, photovoltaic panels). The landlord must then have a new EPC certificate established that replaces the old one. For indexation, it is the class in force at the indexation date that counts — so a renovation from G to C before the anniversary allows recovering 100% of the indexation for that year (Brussels pre-2022, Flanders).
Is there a difference between the kWh classes per region? + −
Yes. Precise thresholds differ between Wallonia, Brussels and Flanders, because the calculation methodologies (Espec, EW, E-peil) are not identical. This complicates inter-regional comparisons — a Walloon B is not exactly equivalent to a Flemish B. For indexation, it is the gross class (letter) that counts, not the kWh value. Our tableau below gives the main ranges per region.
Calculate your indexation
Our tool automatically applies the Belgian legal formula with up-to-date Statbel indexes.
Go to the calculator →This article is informational and does not constitute legal advice. For any disputed or complex situation, consult a lawyer or the justice of the peace of the property's commune (free procedure).