RE2020: the ICénergie index

The objective is twofold in terms of energy performance. RE2020 should enable the construction of buildings that consume less energy and also use less carbon-intensive energy sources. Thus, for the first time, the regulations set a maximum threshold for greenhouse gas emissions from energy consumption. The_ICénergie indicator was created with RE2020. Find out everything you need to know about this index and its influencing factors here!

Definition of the_ICénergie index

The_ICénergie indicator assesses the impact on climate change of energy consumption during the use of the building throughout its lifetime (set at 50 years). This impact is measured in kg of_CO2 equivalent emitted into the environment per^m2 of gross floor area or usable floor area.

It complements the_{ICconstruction} index, which represents the impact of construction products and equipment and their implementation on climate change. These two indicators make it possible to represent the impact of a new construction on climate change.

_ICenergy indicator values in RE2020

The_ICénergie index is expressed inkg_CO2/m² and must remain below the_{ICénergie_Maxmoyen} defined in RE2020.

The pivot values for_{ICénergie_maxmoyen} for an average building are as follows:

• 160 kg_CO2/m² in detached or semi-detached houses
• 560 kg_CO2/m² in multi-family housing (to gradually reach 260 kg_CO2/m² by 2028).

Calculation of the_ICenergy indicator

The _{ICénergie_max} is calculated based on the_{ICénergie_maxmoyen}:

_{ICenergy_max}=_{ICenergy_maxaverage} × (1 + Mcgeo + Mccombles + Mcsurf_avg + Mcsurf_tot + Mccat)

With:
Mcgéo = modulation coefficient based on the geographical location (geographical area and altitude) of the building
Mccombles = modulation coefficient based on the floor area of converted attic space in the building (new modulation that allows the Bbio requirements to be adjusted to take into account heated areas with a ceiling height of less than 1.80 m (not included in the SHAB))
Mcsurf_moy = modulation coefficient based on the average surface area of the dwellings in the building or part of the building
Mcsurf_tot = modulation coefficient based on the total surface area of the building
Mccat = modulation coefficient based on the category of external constraints on the building (reformulation of categories CE1 and CE2 of RT 2012). Mccat compensates for external constraints that limit the possibilities for natural ventilation of the building by opening windows (Br2, Br3), when this requires the use of an air conditioning system for buildings in the Mediterranean coastal and inland regions (H2d and H3).

Like the Cep and Cep,nr indicators, the_ICénergie index is adjusted according to geographical location, average housing size, building size, converted attic space, and external constraints category.

Example of_{ICénergie_max} for a single-family home / for a multi-family building (in kg_CO2/m²):

Levers of influence of the_ICénergie index

Some levers identified in 2021 by CEREMA¹ that can influence the_ICénergie index:

In multi-unit dwellings:

– Low-carbon concrete: around -50 kg_CO2/m²
– Use of low-carbon products in finishing work: -100 kg_CO2/m² 
– Wood structure (CLT): -150 to -200 kg_CO2/m²
– Optimization of environmental data: -50 kg_CO2/m²

In single-family homes:

– Use of low-carbon products in finishing work: -100 kg_CO2/m²
– Wood structure: -150 kg_CO2/m²
– Optimization of environmental data: – 50 kg_CO2/m²

The_ICénergie indicator is an index used to measure the environmental impact of a building's energy consumption. It thus meets a dual objective of RE2020: to construct buildings that consume less energy and to reduce the carbon impact of these buildings. It complements the Bbio, Cep, and Cep,nr indices. It is an energy consumption performance indicator, although its performance is viewed from the perspective of greenhouse gas emissions.

1. Source: https://www.cerema.fr/system/files/documents/2021/12/ctt_re2020.pdf
   ↩︎