RE2020 Regulation for Self-Builders: Complete Guide
What Is the RE2020?
The RE2020 (Réglementation Environnementale 2020 — Environmental Regulation 2020) came into force on 1 January 2022 for detached houses in France. It replaces the previous RT2012 standard and marks a fundamental shift in approach: the focus is no longer solely on energy performance, but also on carbon impact and summer comfort.
For self-builders, this means the project must meet stricter requirements from the design stage — material choices, heating systems, insulation levels, and even resilience to summer heatwaves.
💡 Tip — Even if you self-build, you must comply with the RE2020 as soon as you file a building permit. The RE2020 completion certificate is mandatory when the works are finished.
The 3 Pillars of the RE2020
The RE2020 rests on three fundamental pillars that interact with each other.
1. Energy Sobriety
Like the RT2012, the RE2020 limits energy consumption, but with more demanding indicators:
| Indicator | Meaning | Goal |
|---|---|---|
| Bbio | Bioclimatic needs | Reduce needs before even heating (insulation, orientation, compactness) |
| Cep | Primary energy consumption | Limit total consumption (heating, hot water, lighting, auxiliaries) |
| Cep,nr | Non-renewable primary energy consumption | Favour renewable energy sources |
The Bbio threshold has been lowered by roughly 30% compared to RT2012. This means the building envelope must be significantly more efficient.
2. Carbon Footprint
This is the major innovation. The RE2020 introduces a Life Cycle Assessment (LCA) of the building through two indicators:
- Ic energy: carbon impact of energy consumed over 50 years
- Ic construction: carbon impact of materials and equipment, from manufacturing to end of life
⚠️ Warning — Carbon thresholds become progressively stricter in stages (2022, 2025, 2028, 2031). A project launched today must meet the threshold in force at the time the building permit is filed, not the completion date.
In practice, this favours:
- Bio-sourced materials (timber, straw, cellulose wadding, hemp)
- Low-carbon construction methods (timber frame, rammed earth bricks)
- Decarbonised heating systems (heat pumps, solar, wood)
3. Summer Comfort
The RT2012 only addressed summer comfort in a very basic way. The RE2020 introduces the DH (Degree-Hours of discomfort) indicator, which simulates the number of hours indoor temperature exceeds a comfort threshold.
To meet this criterion, you need to plan for:
- Thermal mass of the building (heavy materials on the inside)
- Solar shading (brise-soleil, overhangs, shutters)
- Night-time ventilation (natural or mechanical over-ventilation)
- External insulation rather than internal in certain configurations
RT2012 vs RE2020: Key Differences
| Criterion | RT2012 | RE2020 |
|---|---|---|
| Effective from | 2013 | 2022 |
| Main indicator | Cep ≤ 50 kWh/m²/year | Reinforced Bbio + Cep + Cep,nr |
| Carbon | Not considered | Mandatory LCA (Ic energy + Ic construction) |
| Summer comfort | TIC (simplified) | DH (hourly simulation) |
| Energy reference | All sources combined | Renewable vs non-renewable distinction |
| Gas heating | Allowed | Banned in new detached houses |
| Bio-sourced materials | No direct incentive | Favoured via Ic construction |
Concrete Impact on Self-Building
Insulation: Aim Higher
The minimum thermal resistances from RT2012 are no longer sufficient. To achieve the required Bbio, you typically need:
| Element | Recommended minimum R (RE2020) | Indicative thickness (mineral wool) |
|---|---|---|
| Walls | R ≥ 4.5 m².K/W | 16 to 18 cm |
| Roof | R ≥ 8 m².K/W | 30 to 35 cm |
| Ground floor | R ≥ 4 m².K/W | 14 to 16 cm |
💡 Tip — For self-build projects, favour external wall insulation (EWI), which eliminates thermal bridges and frees up the thermal mass of internal walls. It pays off in the long term, especially for summer comfort.
Heating: Gas Is Out
Since the RE2020, gas heating is banned in new detached houses. The preferred solutions are:
- Air-to-water or air-to-air heat pump (the most common)
- Wood-burning stove or pellet stove as a complement
- Solar thermal for domestic hot water
- District heating if available
Materials: Think Carbon
Every material carries a carbon weight. The self-builder must factor this into their choices:
- Concrete is a major CO2 emitter — limit its use to the essentials (foundations, slabs)
- Timber stores carbon — favour timber frame, timber cladding, traditional roof structures
- Bio-sourced insulation (cellulose wadding, wood fibre, hemp) has a much better Ic construction score than polystyrene
Airtightness: Still Essential
The RE2020 maintains the requirement of Q4Pa-surf ≤ 0.6 m³/(h.m²) for detached houses. In self-build projects, this is often the trickiest point. Pay particular attention to:
- Wall-to-window junctions
- Pipe and duct penetrations
- The loft hatch surround
- Sockets and switches on external walls
⚠️ Warning — A blower door test is mandatory at handover. If the result exceeds the threshold, you will not be able to obtain the RE2020 completion certificate. Prepare by carrying out an intermediate test during construction.
What to Plan from the Start
- Commission an RE2020 thermal study before filing the building permit
- Choose a construction method compatible with carbon thresholds (timber frame, brick, etc.)
- Plan for enhanced insulation (walls, roof, ground floor)
- Select a decarbonised heating system (heat pump, wood, solar)
- Integrate summer comfort from the design stage (orientation, solar shading, thermal mass)
- Schedule airtightness testing (intermediate + final)
- Check the Ic construction thresholds in force at the time of the permit application
- Keep FDES/PEP datasheets for all materials to justify the LCA
Key Takeaway
The RE2020 is a profound evolution of French building regulations. It pushes self-build towards more virtuous practices: bio-sourced materials, decarbonised heating, enhanced insulation, and year-round comfort. It is a more demanding framework, but also an opportunity to build better and more sustainably. Engage a thermal engineering consultancy from the very start of your project — it is an investment that will save you from costly mistakes.