1. Price decote formula
The price decote is the average price gap between a property of a given DPE label and an equivalent D-rated property (market reference). Source: OneDpe "green value" calibration on DVF transactions matched with DPE certificates (2025 corpus). External benchmark, cited for comparison and not as the source of our table: the Notaires de France "valeur verte" study on 2024 transactions (hedonic regression, 552,850 transactions modelled) measures -25% on G-rated houses and -12% on G-rated flats.
prix_attendu = prix_affiche × (1 - decote_pourcentage)
fourchette_basse = prix_affiche × (1 - decote_max)
fourchette_haute = prix_affiche × (1 - decote_min)The decote table is cross-referenced (DPE label × property type: house / apartment / building). Regional variants are applied automatically from the postal code for labels E, F and G: up to 11 calibrated regions (Paris intra-muros -10%, Lyon, Marseille, Aquitaine, rural Nouvelle-Aquitaine -27%, etc.); for apartments, an additional "Paris prime" variant applies (arrondissements 1-8, 16, 17 above €12,000/m², where land scarcity offsets part of the DPE penalty). For building-type properties and (label, region) pairs without a calibrated variant, a national average is applied with a disclaimer.
2. Energy cost projection
Annual energy cost is estimated from FINAL energy consumption — the energy that is actually billed — the living area and the average price of the main energy source. Consumption comes from the looked-up DPE when its number is provided; otherwise it is a reference value at the middle of the class range, not a per-building 3CL calculation. A DPE states consumption in primary energy: it is converted to final energy using the regulatory coefficient of the carrier before any price is applied, since the price is a price per billed kWh:
conso_finale = conso_primaire_kWh/m²/an ÷ coef_energie_primaire
cout_annuel = conso_finale × surface × prix_€/kWh
cout_N_ans = Σ_{i=0..N-1} cout_annuel × (1 + inflation)^i- Primary energy coefficient: for electricity, 1.9 (the mainland-France scale at which ADEME's database is observed, where the certificate states no final energy); 1.0 for all other energies
- No COP is applied to the cost: a DPE's consumption already accounts for the installed generator's efficiency, heat pumps included. The heat pump type therefore does not enter this calculation.
- Default inflation: +3%/year (CRE 2025-2030)
3. Renovation budget & aids
The renovation budget estimates the cost to reach the target class (D by default) from the current label. For a house, it starts from a pre-calibrated typical bundle per transition (roof / wall / window insulation, VMC, heat pump depending on the transition), taken as reaching the target.
For a whole building (property type "Building / collective", or an assessment issued for the entire building), no works budget and no grant is estimated; the results page says so as follows: “This assessment covers the whole building. This tool prices the works and grants for a single home: it cannot do so from a building-wide assessment. For your home, enter your own unit's DPE; for works on the whole building, an energy audit of the building is what allows them to be priced.”
In an apartment, only the works the home can carry out alone are priced: each measure of the typical bundle is replaced by the one the "Renovation Works" tool offers the home — internal instead of external wall insulation, humidity-controlled VMC instead of double-flow VMC, window replacement instead of loft insulation, a heat-pump water heater instead of the heat pump or solar water heater when the home's hot water is proven to be individual — and the heating system is not replaced. A measure is only priced if the EPC record's data do not rule it out (windows already very well insulated, a home too recent for that measure…). If you build the bundle yourself, the "Customize work bundle" card only offers, for an apartment, the measures the "Renovation Works" tool offers that home, retained by the same EPC record rules; for a house, it offers its usual catalogue, except insulating a lowest floor that the "Renovation Works" tool does not offer either: a floor already very well insulated, a floor to which the assessment attributes no heat loss (0 W/K), or a floor lying entirely on the ground. What you tick is then priced as you chose it. In an apartment, only the home's own works are priced, with the estimated class after these works, which may stay worse than the target class; co-ownership works are named but not priced. “In an apartment, these works usually concern the common parts or the building's equipment: they then fall to the co-ownership and are decided at the general meeting. They are priced here neither in cost nor in grants: this bundle only counts the works in your own home.”
For an apartment, the class reached is not presumed: it is estimated on these works alone, and the page writes it above the budget ("estimated class after these works"). The MaPrimeRénov' supported pathway, which requires a gain of at least two classes for the first stage of works (order of 17 November 2020, art. 13-2, 1° a)), is only priced if that estimate reaches it; otherwise, the page says why it is not, with this caveat: “If these works are a later stage of a renovation path already under way, your renovation coordinator can tell you whether the condition applies.” MaPrimeRénov' aids and CEE are deducted based on the selected income category, where they are estimated (see overseas France below); the Éco-PTZ is NOT — it is a loan, which finances the remaining cost.
Overseas, the page applies the following rules and writes them under the budget of the home concerned. Outside mainland France: “The MaPrimeRénov' supported pathway (whole-home renovation) is only open to homes located in mainland France (decree no. 2020-26, art. 2, I, 1°): it is neither offered nor estimated here for your home.” In Guadeloupe, Martinique, French Guiana, Réunion and Mayotte, single-measure grants are still estimated: “Home in an overseas department: the grants shown follow the mainland France scale and may differ for your home.” CEE bonuses there are estimated with mainland France sheets, in climate zone H3 (order of 22 December 2014, art. 4), except for works with no applicable mainland sheet: “CEE bonuses not estimated here: sheet specific to French overseas territories. Solar water heaters fall under a CEE sheet reserved for French overseas territories (order of 22 December 2014, art. 4); roof and wall insulation falls under such sheets for works committed until 30 April 2027 (sheets BAR-EN-106 and BAR-EN-107, repealed from 1 May 2027). This tool does not apply these sheets, and no amount calculated for your home includes them.” “Air-to-air heat pump: CEE bonus not estimated here in French overseas territories. The sheet specific to those territories (BAR-TH-141) only covers replacing an existing air conditioner in an apartment, and this tool does not estimate that case; no amount calculated for your home includes it.” “Flat roof insulation: CEE bonus not estimated here in French overseas territories. The sheet specific to those territories (BAR-EN-106) is titled "Insulation of lofts or roofs", but only covers lost lofts and roof slopes (§ 2); as it is not known whether it rules out the flat roof sheet (BAR-EN-105), this tool does not estimate this case; no amount calculated for your home includes it. Both sheets (BAR-EN-105, BAR-EN-106) are repealed from 1 May 2027.” “CEE bonuses not estimated here: sheet reserved for mainland France. For ventilation, system flushing and combined solar systems, the CEE sheet only covers mainland France, and the ministry catalogue has no sheet specific to French overseas territories for these works; no amount calculated for your home includes them.” In Saint-Pierre-et-Miquelon, Saint-Barthélemy, Saint-Martin and for postcodes starting with 98: “MaPrimeRénov' and energy savings certificate (CEE) bonuses are not estimated here for your home: whether they apply where it is located has not been verified, and no amount calculated for your home includes them.” “The Eco-PTZ is not estimated here for your home: this loan rests on a tax credit under the French General Tax Code (art. 244 quater U), and whether it applies where your home is located has not been verified. The collectivities of Saint-Pierre-et-Miquelon, Saint-Barthélemy and Saint-Martin, in particular, set their own rules on taxes, duties and levies, the latter two under conditions set by the French General Code of Local Authorities (CGCT, art. LO 6414-1, II, 1°, LO 6214-3, I, 1° and LO 6314-3, I, 1°).”
remaining_cost = max(0, total_works_cost - maprimerenov - cee
+ supported_pathway_remaining_cost)
actions = distinct actions opened by the bundle (CCH, art. D. 319-16, I, 1°)
eligible_cost = cost incl. VAT of the measures attached to an action only
cap = €7,000 (glazing and doors only) | €15,000 (1 action)
| €25,000 (2 actions) | €30,000 (3 actions or more) — art. D. 319-21
eco_ptz = min(cap, eligible_cost) — art. D. 319-54. Regulatory sources
- OneDpe "green value" calibration — DVF transactions, 2025 corpus (decote table per label × property type × region)
- External benchmark: Notaires de France — "La valeur verte des logements en France", 2024 transactions (hedonic regression, 552,850 transactions modelled) — cited for comparison, not the source of our table
- BDNB CSTB 2025 — Reference median price per commune (5,533 communes), for the median-price line in results
- CRE — Energy price trajectory 2025-2030 (default inflation +3%/year)
- ADEME — 3CL coefficients (kWh/m²/year per DPE label; primary-to-final conversion for electricity at a factor of 1.9 (the mainland-France scale at which ADEME's database is observed, where the certificate states no final energy))
- ANAH — MaPrimeRénov' 2026 (subsidies by income category Bleu/Jaune/Violet/Rose)
- Energy decency and letting — In mainland France, a dwelling is deemed non-decent — and can no longer be let as is — from 1 January 2025 if rated G, 1 January 2028 if rated F, 1 January 2034 if rated E. In Guadeloupe, Martinique, French Guiana, Réunion and Mayotte: from 1 January 2028 for class G and 1 January 2031 for class F, class E remaining decent there. Source: Act no. 89-462 of 6 July 1989, art. 6, as worded by Act no. 2021-1104 of 22 August 2021 (Climate and Resilience), art. 160.
- Renovation bundles per transition (G→D, F→D, E→D…) — in-house calibration based on ANAH and CSTB feedback
5. Legal compliance (DGCCRF)
The DPE decote calculator applies our own "green value" table, calibrated on DVF transactions matched with DPE certificates (2025 corpus). The figures are indicative: actual property value depends on specific location, general condition and local market dynamics. In compliance with the DGCCRF, no individual valuation is promised — only a notary or real estate appraiser can value a specific property.
Our approach: (1) all values are presented as "indicative estimates"; (2) low/high ranges are systematically displayed to reflect uncertainty; (3) a disclaimer reminds users that a notary or real estate appraiser remains the sole legally enforceable valuation source; (4) the calculation runs in your browser — if you are signed in, its result is saved to your account so you can find it again.
6. Known limitations
- Regional variants: applied to labels E, F and G — up to 11 regions (house and apartment), plus a "Paris prime" variant restricted to apartments. Building-type properties and non-calibrated (label, region) pairs fall back to the national average.
- Price/m² estimation: at COMMUNE level, via CSTB's BDNB 2025 (5,533 communes), with a fallback to our hand-curated price table (1,117 postcodes, incl. overseas France and Corsica). Outside coverage, the commune concerned is named on screen instead of the line simply disappearing — the percentage decote still applies.
- Granularity: the price reference is at COMMUNE level. In a large or contrasted commune, two neighbourhoods can differ widely from that median — read the gap between the asking price and the commune median with that caveat in mind.
- Energy consumption: middle of the DPE label range (unless actual consumption is entered). For the unbounded G class: 470 kWh/m²/yr (observed G-stock average ≈ 440-500 per Anah).
- Renovation bundle: pre-calibrated per transition (G→D, F→D, etc.); in an apartment, limited to the home's own works (see § 3). For a custom plan (non-standard combination, co-ownership), use the dedicated "Renovation Works" tool.