EPC classes and indexation: complete tableau by class
Understand EPC classes (A to G) and their current impact on rent indexation in Wallonia, Brussels and Flanders. Complete tableau by class.
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 and by the date the lease entered into force: in Brussels (leases that entered into force before 14/10/2022, classes E, F, G) and in Flanders (contracts that entered into force before 1/10/2022, labels D, E, F or no EPC), the indexed rent is multiplied by a correction factor of about 0.89 to 0.99. In Wallonia, classes A-C follow the ordinary formula, while leases rated EPC D to G or without a certificate that had an anniversary during the limitation period (1/11/2022-31/10/2023) have been recalculated since November 2023 under a special method (calculation from the adapted rent).
Quick read: A = excellent / G = catastrophic. For indexation, A-B-C = full indexation everywhere; the poor classes of leases predating October 2022 get a correction factor in Brussels and Flanders, and the adapted-rent method in Wallonia. Calculate the amount applicable to 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 | Wallonia (Espec) | Brussels | Flanders (EPC score) |
|---|---|---|---|
| A++ | ≤ 0 | sub-level of A | — |
| A+ | 0 – 45 | sub-level of A | ≤ 0 |
| A | 45 – 85 | ≤ 45 | 1 – 100 |
| B | 85 – 170 | 46 – 95 | 101 – 200 |
| C | 170 – 255 | 96 – 150 | 201 – 300 |
| D | 255 – 340 | 151 – 210 | 301 – 400 |
| E | 340 – 425 | 211 – 275 | 401 – 500 |
| F | 425 – 510 | 276 – 345 | ≥ 501 |
| G | > 510 | > 345 | does not exist |
Values in kWh of primary energy per m² per year.
Note: each region has its own scale and calculation method — the same letter therefore does not mean the same consumption from one region to another (a dwelling at 300 kWh/m²·year is rated D in Wallonia, F in Brussels and C in Flanders). In Brussels, classes B to E have three sub-levels (+, neutral, −); Flanders itself presents its conversion table as indicative. Sources: SPW Énergie (brochure “Le certificat PEB”), Brussels Environment (official EPB certificate template), vlaanderen.be (explanation of the residential EPC). For indexation, only the letter counts — and the Flemish scale runs from A+ to F: label G does not exist in Flanders.
Recap table: indexation regime by class and region
This is the central table to know for 2026 indexation. In Brussels and Flanders, the criterion is the lease’s date of entry into force (not the date on which it was concluded):
| EPC class | Wallonia | Brussels (in force before 14/10/2022) | Flanders (in force before 1/10/2022) | Brussels and Flanders (more recent leases) |
|---|---|---|---|---|
| A | 100% | 100% | 100% | 100% |
| B | 100% | 100% | 100% | 100% |
| C | 100% | 100% | 100% | 100% |
| D | 100% or adapted rent¹ | 100% | × ≈ 0.945-0.980 | 100% |
| E | 100% or adapted rent¹ | × ≈ 0.945-0.990 | × ≈ 0.891-0.960 | 100% |
| F | 100% or adapted rent¹ | × ≈ 0.891-0.980 | × ≈ 0.891-0.960 | 100% |
| G | 100% or adapted rent¹ | × ≈ 0.891-0.980 | label does not exist | 100% (Brussels) |
| No certificate | 100% or adapted rent¹ | no indexation due² | × ≈ 0.891-0.960 | 100% (Flanders)² |
¹ Walloon special method: for leases that entered into force before 1/11/2022 and had an anniversary between 1/11/2022 and 31/10/2023, the calculation restarts from the adapted rent of that period. Other Walloon leases are indexed at 100%. ² In Brussels, no indexation is due as long as the EPC certificate has not been provided to the tenant, or if the lease is not registered, whatever the date of the lease. In Flanders, no EPC is required to index.
Four key readings:
- Wallonia: no multiplying factor, but D-G leases (or leases without a certificate) that had an anniversary during the 2022-2023 capping period are indexed under a permanent special method (decree of 19 October 2022): the calculation restarts from the adapted rent of that period
- Brussels, leases that entered into force before 14/10/2022: only classes E, F and G are penalised, by a factor that multiplies the full result of the formula (article 224/2, § 1/2 of the Brussels Housing Code); A-B-C-D indexed in full
- Brussels, leases that entered into force from 14/10/2022: no impact of the class — ordinary formula, provided the EPC certificate has been provided
- Flanders: factor for labels D, E, F or no EPC, only for contracts that entered into force before 1/10/2022 (decree of 3 October 2022); a more recent contract is indexed at 100% whatever its label
For the record, different percentages existed during the temporary periods, now ended, when only part of the increase could be claimed:
| Region | Period | Rule applicable at the time |
|---|---|---|
| Brussels | 14/10/2022 → 13/10/2023 | A, B, C, D: 100% · E: at most 50% of the indexation · F, G and no EPC: no indexation |
| Flanders | 1/10/2022 → 30/9/2023 | A+, A, B, C: 100% · D: half of the increase · E, F and no EPC: no indexation |
| Wallonia | 1/11/2022 → 31/10/2023 | A, B, C: 100% · D: 75% of the increase · E: 50% · F, G and no certificate: no indexation |
For regional detail, see our EPC Wallonia, EPC Brussels, and our indexation cap guide.
Worked examples by class
For a base rent of 800 €/month, lease concluded and entered into force on 1 July 2020, indexed on 1 July 2026. Starting index: June 2020 (110.05); new index: June 2026 (139.08); ordinary formula: 800 × (139.08 ÷ 110.05) = 1,011.03 €. Then, depending on the class:
| Class | Wallonia | Brussels | Flanders |
|---|---|---|---|
| A, B, C | 1,011.03 € | 1,011.03 € | 1,011.03 € |
| D | 998.96 € (indexed under the adapted-rent method) | 1,011.03 € | × 0.976119286 = 986.89 € |
| E | 986.89 € (indexed under the adapted-rent method) | × 0.976119286 = 986.89 € | × 0.952238571 = 962.74 € |
| F | 962.74 € (indexed under the adapted-rent method) | × 0.952238571 = 962.74 € | × 0.952238571 = 962.74 € |
| G | 962.74 € (indexed under the adapted-rent method) | × 0.952238571 = 962.74 € | label does not exist |
| No certificate | 962.74 € (indexed under the adapted-rent method) | no indexation due | × 0.952238571 = 962.74 € |
Reading: a G-rated dwelling in Brussels is no longer frozen, but its indexed rent tops out here at 962.74 €, i.e. 48.29 €/month less than the ordinary formula. In Wallonia, this lease had an anniversary on 1 July 2023, during the capping period: classes D to G therefore restart from the adapted rent of 2023. For a lease concluded and entered into force on 1 July 2024, in Brussels as in Flanders, every class gives the same result: 800 × (139.08 ÷ 131.92) = 843.42 €.
To calculate your exact case, the calculator automatically applies the right correction.
Why penalise low classes?
Three converging political objectives in the three 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 reducing indexation as long as the property remains poorly rated, the legislator creates a recurring shortfall. In the example above, the gap reaches 48.29 €/month, i.e. nearly 580 € per year — and it repeats at every indexation. Accumulated over the duration of the lease, this amount weighs in the decision to invest in renovation (typically 20,000 to 50,000 € to move from G to C).
3. Keep the incentive going over time
The Brussels and Flemish correction factors have no end date, and the Walloon adapted-rent method applies until the end of the tenancy. The way out is renovation: in Flanders, the factor stops applying as soon as the landlord obtains a new EPC A+, A, B or C; in Wallonia, a favourable label obtained after renovation allows a return to full indexation (Constitutional Court, judgment no. 64/2024 of 20 June 2024).
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, enough, in Flanders, to get out of the correction factor (EPC C or better) or to switch to the less penalising D factor.
Frequent practical cases
Case 1: I buy a G in Brussels with a 2018 lease
Situation: lease concluded on 12 March 2018 and entered into force on 1 April 2018 (so before 14 October 2022), base rent 800 €, class G. You can index, but with the correction factor — provided the lease is registered and the EPC certificate has been provided to the tenant. On 1 April 2026 (starting index: February 2018, month preceding the conclusion; new index: March 2026): 800 × (137.78 ÷ 106.54) = 1,034.58 €; × 0.931533646 = 963.75 €. What to do?
- Short term: index at the corrected amount, and plan the works
- Medium term: insulate roof + frames to improve the class, then check with be.brussels how the new certificate is taken into account
- Long term: monitor regional announcements on energy requirements
Case 2: My dwelling moves from E to C thanks to works
Situation: Flemish contract concluded on 15 March 2019 and entered into force on 1 April 2019, base rent 800 €, EPC E. On 1 April 2026 (starting index: March 2019, month preceding the entry into force; new index: March 2026), with the EPC E: 800 × (137.78 ÷ 109.04) = 1,010.86 €; × 0.931533646 = 941.65 €. Effect: once the new EPC C is obtained, the correction factor stops applying and the ordinary formula plays in full: 1,010.86 €. Provided that the new certificate is valid — an expired EPC counts as no EPC.
Case 3: Recent lease in Flanders, class C
Situation: Flemish contract concluded and entered into force on 1 July 2024, base rent 800 €, class C. Consequence: the contract entered into force after 1 October 2022, so no factor applies — and the same would hold with an EPC E or no EPC. On 1 July 2026: 800 × (139.08 ÷ 131.92) = 843.42 €.
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 period). Effect: since November 2023, indexation restarts from the adapted rent of that period, with the health index of February 2023 as starting index (special method of the decree of 19 October 2022). In the official example of the Walloon administration (600 €, lease concluded in September 2019 and entered into force on 1 November 2019, EPC E), the adapted rent of 665.24 € on 1 November 2022 becomes 667.22 € on 1 November 2023, against 705.79 € with the ordinary formula. An A-C lease, or a lease with no anniversary in the period, follows the ordinary 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 — correction factor detail for old leases
- EPC and indexation in Wallonia — 2022-2023 period and special method
- EPC hub (all regions) — complete comparison
- How to find the EPC — official sources
- Indexation cap — economic view of the EPC corrections
- Calculate indexation with the right correction — 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 period — in Wallonia. Identifying it correctly before notifying is now as important as verifying lease registration. This information is provided for guidance only and does not constitute legal advice.
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), G the worst (very high consumption). Each region has its own scale; the table in the article shows the three official scales. 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 on the date the lease entered into force. In Brussels, for leases that entered into force before 14 October 2022, the indexed rent is multiplied by a correction factor of about 0.945 to 0.990 in class E and of about 0.891 to 0.980 in classes F and G; classes A to D are indexed at 100%. In Flanders, for contracts that entered into force before 1 October 2022, the factor is about 0.945 to 0.980 for an EPC D and about 0.891 to 0.960 for an EPC E, F or no EPC; label G does not exist there. More recent leases are indexed at 100% in both regions. In Wallonia, leases rated EPC D to G or without a certificate that had an anniversary between 1 November 2022 and 31 October 2023 have followed, since 1 November 2023, a permanent special method (calculation from the adapted rent); classes A to C and more recent leases follow the ordinary formula.
If my dwelling is rated G, can the landlord refuse to do the works? + −
The indexation rules do not impose works on the landlord, but they penalise him as long as the dwelling remains poorly rated: in Brussels, a lease that entered into force before 14 October 2022 with an EPC G sees its indexed rent multiplied by a factor of about 0.891 to 0.980. In Flanders, a new EPC A+, A, B or C puts an end to the correction factor; in Wallonia, a favourable label obtained after renovation allows a return to full indexation. Any renovation obligations fall under other regional legislation: check the official sources.
Can the EPC evolve during the lease? + −
Yes, following energy renovation works (insulation, frames, boiler, photovoltaic panels). The landlord then has a new certificate established that replaces the old one. In Flanders, the correction factor stops applying if the landlord obtains a new EPC A+, A, B or C (moving from E or F to D switches to the D factor); conversely, an expired EPC counts as no EPC. In Wallonia, a favourable label obtained after renovation allows a return to full indexation. For Brussels, check the effect of a new certificate with be.brussels.
Is there a difference between the kWh classes per region? + −
Yes. Precise thresholds differ between Wallonia, Brussels and Flanders, because each region has its own calculation method and scale. A Walloon B runs from 85 to 170 kWh/m²·year, a Brussels B from 46 to 95, a Flemish B from 101 to 200: inter-regional comparisons are therefore meaningless. For indexation, it is the gross class (letter) that counts, not the kWh value. Our table below gives the official scales of the three regions.
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 (low-cost procedure, no lawyer required).