The overall premium by building type
Studies published by the industry bodies, the national energy agency, the developers' federation and thermal engineers between 2022 and 2025 converge on the following ranges. They represent the construction premium excluding VAT against a building compliant with the previous thermal standard, at identical brief and standing.
| Building type | Premium against the previous standard | Range by constructional choice |
|---|---|---|
| Individual house | + 4 to 8 % | + 3 % with an air-source heat pump and standard external insulation, to + 12 % with timber frame and ground-source |
| Apartment building | + 3 to 7 % | + 2 % with low-carbon concrete and a communal heat pump, to + 10 % with timber frame |
| Offices | + 5 to 12 % | + 4 % with concrete structure and a heat pump, to + 15 % for a positive-energy building |
| Education | + 4 to 9 % | Variable with site and brief |
| New hotel | + 3 to 8 % | According to star rating and energy systems |
These are orders of magnitude. The real premium depends on the outline assumptions: climate zone, density, height, brief, site constraints.
A more recent assessment is available. An official review delivered to the housing ministry in July 2025 puts the average premium induced by the 2025 step alone at 90 to 150 €/m² according to type. That review led to the decree of 18 March 2026, applicable to applications filed from 1 July 2026, which relaxes the requirements for roof extensions and introduces three modulating coefficients for apartment buildings. The decree of 15 January 2026 separately extended the regulations to thirteen categories of commercial and industrial buildings for applications filed from 1 May 2026, bringing programmes previously outside the scope into the premium calculation.
Where the premium comes from
1 The envelope: reinforced insulation
The regulations require the bioclimatic indicator to improve by at least 30 % against the previous standard. In practice that means reinforced thermal insulation: 20 to 40 mm more on the opaque envelope, triple glazing mandatory in the coldest zone, and movable solar protection — external blinds, shutters — mandatory on exposed façades.
| Envelope item | Effect against the previous standard | Indicative premium |
|---|---|---|
| Wall insulation | 20 to 40 mm more thickness | + 5 – 12 € excl. VAT per m² of floor area |
| Roof and ground floor insulation | Thickness taken to 200–300 mm | + 3 – 8 € excl. VAT per m² of floor area |
| Glazing | Double to triple in the coldest zone | + 20 – 40 € excl. VAT per m² of glazing |
| Solar protection | External blinds or brise-soleil mandatory | + 40 – 100 € excl. VAT per m² of south or west façade |
| Air permeability | Testing mandatory | + 1,500 – 3,000 € excl. VAT per building |
2 Energy systems: the end of gas
The effective prohibition of gas boilers in new buildings — through carbon and energy thresholds that penalise gas heavily — is the most structuring measure. It requires heat pumps, whether air-source, air-to-water or ground-source, solar thermal or biomass. That change is the most significant premium for individual houses.
| System | Cost under the previous standard, gas | Cost under the current regulations, heat pump | Premium |
|---|---|---|---|
| Heating a 90 m² house | Gas boiler: 3,000 – 6,000 € | Air-to-water heat pump: 8,000 – 15,000 € | + 5,000 – 9,000 € |
| Heating an apartment, per dwelling | Communal gas: 2,000 – 4,000 € | Communal heat pump, pro rata: 4,000 – 8,000 € | + 2,000 – 4,000 € |
| Domestic hot water in an apartment | Gas water heater: 1,500 – 3,000 € | Thermodynamic cylinder: 3,000 – 6,000 € | + 1,500 – 3,000 € |
| Cooling offices | Gas plant with chillers: 60 – 100 €/m² | Reversible heat pump: 70 – 120 €/m² | + 10 – 20 €/m² |
3 Low-carbon materials and the life-cycle assessment
The construction carbon indicator requires the footprint of the materials to be limited. Standard reinforced concrete is penalised, since a high cement content means a high footprint. The alternatives — low-carbon concrete, timber frame, cross-laminated panels, bio-based insulation such as hemp, cellulose and straw — have a lower footprint but a purchase premium.
| Material | Typical construction carbon | Premium against standard concrete |
|---|---|---|
| Standard reinforced concrete | 250 – 350 kg CO₂ eq./m² | The reference |
| Low-carbon concrete | 120 – 180 kg CO₂ eq./m² | + 3 – 8 % on the structural cost |
| Cross-laminated timber frame | −50 to −150 kg CO₂ eq./m², through sequestration | + 10 – 20 % on the structural cost |
| Glass or mineral wool insulation | Low | The insulation reference |
| Cellulose insulation | Very low, negative where recycled | + 15 – 30 % against mineral wool |
| Hemp insulation | Very low | + 20 – 40 % against mineral wool |
4 Additional studies and certificates
The regulations create study and certificate obligations beyond the previous standard. These costs are often neglected in initial feasibility studies.
| Additional mission | Who carries it out | Estimated cost excl. VAT |
|---|---|---|
| Dynamic life-cycle assessment | Thermal engineer with approved software | 2,000 – 8,000 € according to the size of the operation |
| Construction carbon calculation | Thermal engineer | Included in the thermal mission, plus 500–2,000 € |
| Air permeability test | A certified operator | 1,500 – 3,000 € per building |
| Compliance certificate with the application | Design team or thermal engineer | Fees included in the mission |
| Completion certificate | Architect, assessor, technical controller or certifier | 1,500 – 4,000 € according to the building |
| Complete thermal engineering mission | An approved thermal engineer | 0.5 – 1.5 % of the works cost excl. VAT |
What the regulations save
If the regulations generate a capital premium, they must be assessed on their overall return. The energy savings over the life of the building can amply offset the initial premium.
| Indicator | Previous standard | Current regulations | Estimated annual saving |
|---|---|---|---|
| Consumption, individual house | Below 50 kWh/m²·year | Around 30 kWh/m²·year | 200 – 400 € a year per dwelling |
| Consumption, apartment | Below 57.5 kWh/m²·year | Around 40 kWh/m²·year | 150 – 300 € a year per dwelling |
| Consumption, offices | Below 100 kWh/m²·year | Around 60 kWh/m²·year | 300 – 600 € a year per 100 m² |
| Emissions, gas-heated house | Around 1.5 t CO₂ a year | Around 0.2 t CO₂ a year | −1.3 t CO₂ a year |
Over 20 years, assuming energy prices rise 4 % a year, the discounted gain per apartment is of the order of 5,000 to 12,000 €, giving a payback of 7 to 15 years on the average premium.
Trade-offs that limit the premium
1 Optimise the envelope through bioclimatic design
A bioclimatic approach — optimal orientation, compactness, passive solar gain, summer shading — significantly reduces the bioclimatic indicator at no material cost. A well-oriented building can meet the requirement with standard insulation, saving 5 to 10 € excl. VAT per square metre on the envelope.
2 Low-carbon concrete against changing construction system
Low-carbon concrete is generally the cheapest way to improve the construction carbon indicator, at 3 to 8 % on the structural cost alone, against a complete switch to timber at 10 to 20 %. For standard apartment programmes, low-carbon concrete remains the economically optimal choice in most cases.
3 Communal against individual heat pumps
In apartment buildings, a communal air-to-water heat pump with a distribution network is generally cheaper to install than individual units per dwelling, while performing better on energy carbon. The investment is larger but the operating cost is lower.
The economist's role
The construction economist occupies a strategic position in optimising compliance. Their role goes beyond pricing the items: they must weigh the technical solutions proposed by the thermal engineer and the design team by quantifying the premium of each option; verify that the specification requires the manufacturers' environmental declarations needed for the carbon calculation; anticipate the future carbon thresholds of 2025 and 2028 to avoid redesign; and value the operating savings in feasibility analyses for developers.
ℹ ✔ The figures in summary Overall premium against the previous standard: + 3 to 8 % for housing, + 5 to 12 % for commercial. Principal items: envelope (+ 3–12 €/m² of floor area), heat pump (+ 510–1,530 € per dwelling), life-cycle assessment and studies (+ 0.5–1.5 % of engineering fees). Low-carbon concrete is the optimal cost-to-carbon solution for ordinary housing. Thermal engineering: a fee budget of 0.5–1.5 % of the works cost, to build in from feasibility. Completion certificate: 1,500 – 4,000 € excl. VAT to allow for. Return over 20 years: 5,000 – 12,000 € of discounted energy savings per dwelling.
Links to the related articles
The environmental regulations article develops the indicators, thresholds and calculation method in full. The new apartment and new house articles apply that data to residential types. The residential block article covers the constraints specific to apartment buildings. The refurbishment article clarifies why the regulations do not apply to renovation.
ℹ The construction economist on demand. The environmental regulations applied to your programme: Quostra prices the premium item by item, coordinates the thermal engineer and delivers a precise estimate from the outline stage.
Sources: the official guidance of May 2025; the decree of 29 July 2021; the order of 4 August 2021 as amended; the industry feedback reports of 2023–2024; the national energy agency's guide to bio-based materials; and the national environmental product database.
Reference basis of the figures
The ratios per square metre and per item on this page are stated in January 2026 values. They were updated from January 2025 values, the basis adopted for the whole cocoon, using the BT01 all-trades index published monthly by INSEE on its 2010 base: 132.0 in January 2025, 134.7 in January 2026, a coefficient of 1.0205.
The global amounts quoted as examples, and any rents, charges or receipts expressed per year or per night, remain on their own basis: a building cost index does not apply to them.
To bring the ratios forward, apply the usual revision formula: updated value = page value × (BT01 for the month in question / 134.7). The BT01 measures contractors' input costs, labour at 44.9 % and materials at 36.5 %, not the prices actually tendered.