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Why a high thermal rating matters in construction
How smart, energy efficient sustainable design can improve thermal comfort, lower heating bills
and reduce carbon emissions
Why is achieving a high thermal rating for your property important?
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A comfortable living environment in a property which is energy efficient and cost-effective to run is a goal that all homeowners will agree with. Properties which have high levels of thermal efficiency will maintain a stable indoor temperature, using minimal amounts of energy; characteristics which benefit the planet and your wallet. Furthermore, in France, achieving a high thermal rating for a building is a key principle behind the RE2020 regulation. In this article, we look at the key elements which are driving the standards, effective passive design strategies, the critical importance of air tightness as well as other key considerations.
Why are the RE2020 regulations significant?
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RE2020 – the Réglementation Environnementale 2020 – is a French regulation introduced to improve the energy and environmental performance of all buildings. France first introduced the RE2020 standards in January 2022 for new housing schemes, and they extended them to encompass all commercial properties in January 2024.
According to research, buildings are currently responsible for 39% of global energy related carbon emissions. This therefore makes it imperative that construction projects – whether they are for new build or to renovate existing buildings – achieve the highest possible technical standards of thermal comfort, reducing carbon emissions through meticulous material selection and life cycle analysis.
Which types of construction does the RE2020 apply to?
Meeting or exceeding RE2020 standards applies to virtually all building construction in France, whether it is a commercial, industrial or residential project. This includes all new constructions and significant extensions. That’s why understanding the scope of the regulation is crucial before seeking a building permit or planning permission. Though renovations do not always require RE2020, authorities will often apply it in practice, and a formal declaration of completion now necessitates an initial RE2020 attestation.
Undertaking a project which adheres to RE2020 standards is not just about following a regulation though; it has practical benefits. For example, in a home built to RE2020 specifications, superior insulation, ventilation, and considerations of orientation can help to naturally regulate indoor temperatures, reducing the need to turn on the air conditioning on a summer's day or reducing the heat load over the winter. It is worth noting that RE2020 is, however, the minimum requirement for thermal performance of new constructions.
Effective passive design strategies
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If you are looking to construct or renovate a property to the highest possible standards, achieving Passivhaus certification is the highest benchmark for energy efficiency, sustainability and thermal comfort. Think of it as the ‘gold standard’ in sustainable construction. It is not however a regulatory requirement in terms of RE2020.
Passive design strategies are sustainable architectural practices that seek to minimise the impact of building design on the environment. The Passivhaus certification, developed in Germany, is the most forward-thinking example of an effective passive design strategy internationally. Today, builders have successfully constructed thousands of buildings using the Passivhaus approach. There are five underlying principles to passive design:
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High quality insulation
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Exceptional air tightness
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Heat control and robust windows and doors
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Mechanical heat recovery and ventilation (MVHR): for example, extracting stale air from kitchens and bathrooms and drawing in fresh, filtered outdoor air
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Thermal bridge free design: A thermal bridge is a localised weakness in a building's insulation where heat can easily escape or enter, leading to energy loss, discomfort, and potential condensation issues. Designers can eliminate a thermal bridge at the design stage by applying passive design principles.
Each of these five principles work together to create a building envelope that drastically reduces energy consumption, maintains stable indoor temperatures, and ensures a high level of occupant comfort and indoor air quality.
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Furthermore, a priority should be to use natural and low carbon materials wherever possible, as well as taking account of orientation and solar shading.
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The importance of air tightness
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Air tightness reduces heat loss, improves comfort and overall protects the fabric of the building. However, it’s really difficult to get right if you don’t think about the issue from the beginning. If you wait to address the matter until after you build the property, you'll find it extremely tricky to correct and achieve the necessary air tightness. It is therefore important to look at air tightness in the whole of the building; windows, doors, chimneys… even letter boxes from which a large amount of heat can escape. If you want to check the foundations of a building, you will need to contact a structural engineer… by the same token, for air tightness an environmental engineer will check the plans to ensure they meet the requirements.
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Windows and doors
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Generally, standard double glazing with PVC frames meets French regulations; the key is how you integrate them with the insulation layers. In addition, focus on proper installation to ensure air tightness and minimise thermal bridging; it may be more cost-effective and beneficial especially if your project budget cannot afford, for example, triple glazing with timber frames.
Investment and payback periods
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The financial investment and potential payback periods unsurprisingly vary from project to project, and you can often achieve the most significant savings by applying effective design principles, which require no additional material costs.
As a general guide, achieving a high thermal rating might involve an initial investment increase of around 10 to 15%. However, there is a payback in terms of energy savings and improved thermal comfort. It is also true that a sustainable building sells! People are increasingly valuing the importance of energy efficiency and high thermal performance in their homes and offices.
Planning permission and building permits
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Unfortunately, achieving a very high thermal rating doesn’t offer many advantages in planning terms, French planning policy hasn’t meshed with environmental regulations yet. There is a requirement to demonstrate that the design has been developed to meet minimum RE2020 standards but there are few specific planning regulations associated with thermal performance, but, where new policy is being developed there appears to be a move to promote sustainability within specific regulatory frameworks. However, high-performing buildings often gain better access to financial aid and subsidies from the state, and their lower energy bills and sustainability will likely increase their market value.
Contact us
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French Plans has over 20 years’ experience helping people to apply for building permits or planning consents in France. We are fully qualified English speaking architects and planning consultants.
We also work with building professionals of all kinds, such as structural engineers, thermal engineers and surveyors.
If you are looking to realise your own project in France, whether it is a renovation, a new build, an extension or another project, residential or commercial – please get in touch.
+33 (0) 6 75 05 36 86