RE2020: here are the 5 important points to know in 2024 in France

Here are the five most important technical points of the guide on Environmental Regulations 2020 (RE2020) for new buildings: SUMMARY.

1. Energy and environmental performance :
   • RE2020 introduces reinforced requirements for the energy performance of new buildings, taking into account not only energy consumption for heating, cooling, domestic hot water, ventilation and lighting, but also environmental impacts. linked to this consumption over the entire life cycle of the building. This regulation also includes internal mobility needs (elevators, escalators) and energy consumption linked to car parks and common areas.
2. Performance indicators :
   • The regulation is based on several key indicators:
     • Bbio : Bioclimatic requirements to assess the building's energy needs for heating, cooling and lighting.
     • Cep : Total primary energy consumption.
     • Cep,nr : Consumption of non-renewable primary energy.
     • Icconstruction : Environmental impact of construction materials and energy consumed during construction.
     • DH : Degree-hour of discomfort to measure thermal comfort in summer.
3. Life cycle assessment :
   • RE2020 introduces life cycle analysis (LCA) of buildings, which means that environmental impacts are assessed from the production of materials until the end of the building's life, including operation, maintenance, and treatment of construction waste.
4. Taking summer comfort into account :
   • The RE2020 replaces the Tic indicator of the RT 2012 with a new DH indicator, which takes into account thermal discomfort during heatwave periods. This change reflects better adaptation to increasingly frequent heat waves, by anticipating the impacts of climate change on buildings.
5. Modulation of requirements :
   • The requirements of the RE2020 are modulated according to several parameters such as geographic location, size of housing, total surface area of ​​the building, and the presence of external constraints. These modulations make it possible to adjust the requirements in order to take into account the specificities of each project, including the use of default data when specific information is not available. More details below :

1-Energy and Environmental Performance in RE2020

There Environmental Regulations 2020 (RE2020) marks an important turning point in the way in which the energy and environmental performance of new buildings is assessed in France. By replacing RT2012, RE2020 broadens energy performance requirements while integrating new environmental considerations over the entire life cycle of the building. Here is an in-depth development of this first crucial point.

1.1. Expansion of the Scope of Energy Performance

Under RT2012, the assessment of new buildings mainly focused on five essential energy uses: heating, cooling, domestic hot water production, ventilation, and thelighting. RE2020 uses these criteria but adds other elements for a more complete approach:

• Internal mobility : There electricity consumption necessary for elevators, escalators, as well as lighting and ventilation of parking lots, is now an integral part of the calculation of the energy performance. This inclusion is crucial for collective buildings, where these systems represent a significant part of energy consumption.
• Energy consumption linked to car parks : Lighting and ventilation of parking lots, often ignored in previous assessments, are now taken into account to give a more accurate picture of a building's energy needs.

1.2. Integrated Approach to Environmental Impact

RE2020 goes beyond simple energy efficiency by introducing a comprehensive environmental assessment, based on the life cycle analysis (LCA) of the building. This method takes into account environmental impacts from the production of materials to the demolition of the building. It particularly focuses on:

• Building materials : Each material used in construction is evaluated in terms of carbon emissions greenhouse gas (GHG) that it generates, from its production to its implementation. This analysis encourages the use of materials with a low carbon footprint, such as bio-based materials, which store carbon rather than emitting it.
• Energy consumed during construction : The environmental impact of the construction site itself is now assessed, which includes energy consumption and emissions linked to the use of materials, as well as the disposal and treatment of waste.
• Life cycle carbon emissions : The impact of buildings on climate change is now measured over a period of 50 years, covering the construction phase, operation, and the end of the building's life. This allows a more accurate assessment of the building's total CO2 emissions, providing a comprehensive perspective on its environmental impact.

1.3. New Performance Indicators

To measure these broader aspects of energy and environmental performance, RE2020 introduces several new indicators:

• Bbio : This indicator, already present in RT2012, is modified to systematically include cooling needs, whether an air conditioning system is installed or not. This makes it possible to better anticipate future energy needs linked to global warming.
• Cep : THE energy performance coefficient Conventional now includes additional uses such as internal mobility. In addition, renewable energies captured on site and self-consumed are not counted in the building's energy consumption, thus encouraging their use.
• Cep,nr : This indicator is introduced to specifically target non-renewable primary energy consumption. This reflects the objective of reducing dependence on fossil fuels as a priority.
• Icconstruction : This indicator measures the environmental impact of construction materials and processes used during the construction of the building.
• DH : The Degree-Hour (DH) indicator replaces the Tic indicator of RT2012 to better assess thermal comfort in summer, taking into account the effects of climate change.

1.4. Consequences and Implications

The adjustments made by RE2020 mean that new buildings will not only need to consume less energy, but also be designed to minimize their overall environmental impact. These requirements are pushing construction professionals to rethink their working methods, to favor low-impact materials, and to integrate solutions into the design to reduce non-renewable energy consumption. These innovations make buildings more resilient in the face of climate change while contributing to the carbon neutrality objective that France is targeting for 2050. Ultimately, RE2020 represents a major advance in the construction of more sustainable and environmentally friendly buildings. 'environment.

2-Performance Indicators in RE2020

There Environmental Regulations 2020 (RE2020) is based on several key performance indicators that make it possible to measure andassess the energy efficiency and environmental impact of new buildings. Here is a detailed development of these essential indicators:

2.1. Bbio (Bioclimatic Needs)

The indicator Bbio measures the energy needs of the building to ensure thermal comfort and lighting without taking into account the heating systems, cooling, or production ofhot water sanitary. It focuses on the intrinsic performance of the building, that is to say on its ability to maintain thermal comfort and limit energy needs thanks to a design bioclimatic optimal.

• Objective : The Bbio aims to minimize the energy needs linked to the design of the building by optimizing theinsulation, management of solar gain, and natural ventilation. This is about encouraging architectural designs that naturally reduce reliance on mechanical systems.
• Calculation : The Bbio is expressed in points and is calculated according to heating, cooling and lighting needs. These needs are estimated from thermal simulations taking into account the orientation of the building, the characteristics of the materials, airtightness, and passive solar gain.

2.2. Cep (Total Primary Energy Consumption)

The indicator Cep measures the total primary energy consumption of the building for regulated uses, i.e. heating, cooling, domestic hot water production, ventilation, lighting, and auxiliaries (such as pumps and fans). It also includes consumption linked to equipment such as elevators, escalators, and parking lot lighting.

• Objective : Reduce energy consumption by encouraging the use of more efficient systems and equipment, as well as the integration of renewable energy. The Cep also promotes self-consumption of renewable energy produced on site.
• Calculation : The Cep is expressed in kWhep/m².an (kilowatt-hours of primary energy per square meter and per year). It takes into account the efficiency of the installed systems and the use of the building, with a penalty in the event of overconsumption linked to summer discomfort.

2.3. Cep,nr (Consumption of Non-Renewable Primary Energy)

The indicator Cep,nr is similar to Cep, but it focuses only on non-renewable primary energy consumption. This includes fossil fuels such as gas, fuel oil, and electricity from non-renewable sources, while excluding renewable energies such as solar or biomass.

• Objective : Reduce the use of non-renewable energies by promoting the use of renewable energies to achieve the carbon neutrality objectives set for 2050.
• Calculation : As for the Cep, the Cep,nr is expressed in kWhep/m².year. Calculating this indicator makes it possible to assess the building's dependence on non-renewable energy sources and to encourage their substitution by more sustainable energies.

2.4. Icconstruction (Carbon Impact of Construction)

The indicator Icconstruction assesses the environmental impact linked to the construction of the building, based on Life Cycle Analysis (LCA). This indicator takes into account greenhouse gas (GHG) emissions associated with construction materials, equipment, as well as site activities (earthworks, use of machines, waste management, etc.).

• Objective : Reduce the carbon footprint of construction by encouraging the use of materials with a low carbon footprint (such as bio-sourced materials) and by optimizing construction processes to minimize GHG emissions.
• Calculation : Icconstruction is expressed in kgCO2eq/m² (kilograms of CO2 equivalent per square meter). It evaluates all GHG emissions from the production of materials until the end of the building's life, including their transport and their implementation on the construction site.

2.5. DH (Discomfort Degree Hour)

The indicator DH measures the level of thermal discomfort felt by occupants during periods of high heat. It is designed to replace the conventional interior temperature indicator (Tic) of the RT 2012, considered insufficient to correctly assess summer discomfort.

• Objective : Guarantee optimal thermal comfort during summer periods, by anticipating the impacts of climate change, such as the intensification and frequency of heat waves.
• Calculation : The DH is expressed in °C.h (degree-hour). It represents the sum of the temperature differences between the interior of the building and the comfort temperature over the entire hot season. The higher the DH, the greater the discomfort. The maximum regulatory threshold (DH_max) is set to guarantee acceptable comfort, with a penalty in the form of an increase in energy consumption in the event of excess.

3-Life Cycle Assessment (LCA) in RE2020

One of the most innovative and significant aspects of Environmental Regulation 2020 (ER2020) is the introduction of Life Cycle Assessment (LCA) for new buildings. This method represents a major evolution compared to previous regulations, which mainly focused on energy performance during the operating phase of the building.

Principle of Life Cycle Analysis (LCA)

LCA is an assessment method that makes it possible to quantify the environmental impacts of a building throughout its existence. It takes into account all stages of the building's life cycle, from the extraction of raw materials necessary for the production of construction materials to the end of the building's life, including dismantling and waste treatment. The key steps included in the LCA are:

1. Production of materials : Extraction of raw materials, manufacturing of construction materials, transportation to the construction site.
2. Construction and construction site : Energy and water consumption on the construction site, management of waste generated during construction.
3. Operation : Energy consumption for heating, cooling, lighting, ventilation, domestic hot water, and the auxiliaries necessary for the operation of the building.
4. End of life : Demolition, transport of debris, treatment and disposal of waste, recycling potential of materials.

Environmental Indicators Used

To assess environmental impacts throughout this life cycle, RE2020 uses several key indicators:

• Icconstruction : This indicator measures the environmental impact linked to construction materials, their transport, and the construction processes themselves. It also includes the greenhouse gas emissions associated with these activities.
• Icenergy : This second indicator assesses the impact of energy consumption throughout the operating phase of the building, taking into account the energy sources used, whether renewable or not.
• Icbuilding : This global indicator brings together the cumulative environmental impact of all contributions (components, energy, water, construction site) to give a complete vision of the carbon footprint of the building.

Importance of LCA in Building Design

The introduction of LCA in RE2020 aims to encourage more sustainable building design, where the focus is not only on energy efficiency, but also on reducing environmental impacts from the construction phase. This encourages building professionals to:

• Choose materials with low environmental impact : Recycled, biosourced materials, or those that store carbon (such as wood).
• Optimize construction processes : Reduction in energy and water consumption on construction sites, better waste management.
• Anticipate the end of the building’s life : Design for disassembly, reuse and recycling of materials, minimization of non-recyclable waste.

INIES Database

To facilitate the implementation of LCA, RE2020 relies on the INIES database, which brings together the environmental data necessary for assessing the impacts of construction products and materials. This database is essential for providing accurate and reliable information for LCA calculations, allowing professionals to compare and select materials based on their environmental impact.

4-Taking Summer Comfort into Account in RE2020

The 2020 Environmental Regulations (RE2020) introduce significant changes to the way summer comfort is taken into account in new buildings. Unlike the previous thermal regulation (RT 2012), which used the indicator Tic (Conventional indoor temperature) to evaluate summer comfort, RE2020 introduces a new indicator called DH (Degree-Hour of discomfort).

1. Replacement of the Tic Indicator by DH

The Tic indicator, used in RT 2012, measured the maximum temperature reached inside a building during a sequence of five particularly hot days in summer. However, feedback showed that this indicator did not sufficiently correlate with the discomfort felt by the occupants. In other words, the Tic did not always accurately reflect the actual thermal comfort conditions in a building, especially during prolonged heat waves. To address this limitation, RE2020 introduced the DH indicator, which measures the degree of thermal discomfort experienced by occupants throughout the hot season. The DH indicator is expressed in degree-hour (°C.h), which makes it possible to quantify the discomfort accumulated over the entire summer period.

2. Calculation of the DH Indicator

The DH is calculated as the sum of the differences between the interior temperature of the building and a predefined comfort temperature, over all the hot hours of the day and night. The comfort temperature generally varies between 26°C and 28°C, depending on outside temperatures. Each hour that the indoor temperature exceeds this comfort temperature contributes to increasing the total discomfort degree hours. Thus, a building where the interior temperature frequently exceeds the comfort threshold will accumulate a high DH, indicating significant thermal discomfort for the occupants.

3. Taking Future Climate Scenarios into Account

The DH calculation method also integrates future weather scenarios, taking into account the effects of climate change. This includes inserting heatwave sequences into conventional weather files used for simulations. These adjustments are essential because they make it possible to better anticipate and plan the performance of buildings in the face of heat waves, which are expected to become more frequent, intense, and prolonged in the years to come.

4. Discomfort Thresholds and Penalties

RE2020 defines two thresholds of the DH indicator to assess summer comfort:

• Low Threshold : If the DH is less than 350°C.h, the building is considered comfortable even during heatwaves.
• High Threshold (DH_max) : If the DH exceeds a certain threshold (set according to the characteristics of the building and its environment), the building is considered not to comply with the requirements of RE2020.

Between these two thresholds, the building is compliant, but to encourage reaching the low threshold, a penalty in the form of cooling package is added to the total energy consumption of the building (Cep). This penalty is intended to deter designs that fail to maintain adequate summer comfort without excessive reliance on air conditioning systems.

5. Impact on Building Design

The introduction of DH as a key indicator for summer comfort in RE2020 has important implications for building design. Designers must now consider a variety of strategies to limit thermal discomfort:

• Optimization of orientation and thermal inertia : Maximize solar gains in winter while minimizing summer overheating.
• Use of passive materials and systems : For example, effective sun protection, thermal insulation reinforced, and adequate natural ventilation to limit heat accumulation.
• Incorporation of green spaces : These spaces can help reduce the ambient temperature around buildings and improve summer comfort.

5-Modulation of Requirements in RE2020

There Environmental Regulations 2020 (RE2020) introduces a detailed approach for modulating energy and environmental performance requirements. This modulation is essential to adapt the requirements according to the specific characteristics of each construction project. Here is an in-depth development on the different aspects of this modulation:

1. Geographic Modulation (Mcgeo)

• Principle : Geographic modulation adjusts the requirements according to the geographical location of the building. This modulation takes into account climatic differences across France, particularly mountain or seaside areas which may present specific challenges in terms of heating or cooling.
• Impact : For example, a building located in a mountainous region might have less stringent energy performance requirements for heating, given the more severe climatic conditions.

2. Modulation According to the Average Surface Area of ​​Housing (Mcsurf_moy)

• Principle : This modulation aims to balance the requirements between small and large dwellings within the same building. A small home, for example, might have different energy performance requirements compared to a large home due to their respective size and the impact on energy consumption.
• Impact : Small dwellings in a collective building can be favored by a modulation which recognizes their lower impact in terms of overall energy consumption compared to large dwellings.

3. Modulation According to the Total Surface Area of ​​the Building (Mcsurf_tot)

• Principle : This modulation applies particularly to collective buildings and adjusts the requirements according to the total surface area of ​​the building. It takes into account the specific challenges linked to large constructions, such as the management of common areas and collective facilities.
• Impact : Large collective buildings can benefit from a modulation which takes into account the proportionally less impact of common spaces compared to individual housing, which can soften certain energy requirements.

4. Modulation Depending on the Presence of Converted Attics (Mccombles)

• Principle : This modulation takes into account the presence of attic arranged in the building. Attics, often less well insulated and with a ceiling height of less than 1.80 meters, may require adjustments to the requirements so as not to penalize the rest of the building.
• Impact : Modulation makes it possible to adjust the energy performance requirements for these specific spaces, thus preventing the attic from imposing disproportionate constraints on the entire building.

5. Modulation According to the External Constraint Category (Mccat)

• Principle : RE2020 provides for a modulation for buildings subject to significant external constraints, such as exposure to noise (BR2 or BR3) or the need to install air conditioning in certain climatic zones (such as the Mediterranean rim).
• Impact : Buildings exposed to noise pollution which limit natural ventilation by opening windows, or those located in regions where air conditioning is almost essential, will see their requirements modulated to take into account these external constraints.

6. Modulation for Use of Default Environmental Data (Mided)

• Principle : When specific data is not available, RE2020 allows the use of default data, but with modulation that adjusts the requirements to compensate for the lack of precision of this data.
• Impact : This modulation is particularly important for complex or innovative projects where specific data on materials or techniques are not yet fully documented. It allows flexibility while encouraging precision in environmental assessments.

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