Insulation & Renovation

Every year, tens of thousands of buildings undergo insulation work to improve energy performance or renovation and decoration work.

This work can significantly degrade the indoor air quality of buildings and affect the health of occupants.

Why can insulation work degrade indoor air quality?

The purpose of insulation is to limit heat exchange between the outside and inside of a building. The performance of the insulation and therefore energy savings depends on the airtightness of the building.

In a building, air pollution is linked to the use of emissive renovation and decoration materials, the presence of furniture (agglomerated wood), the use of household and cosmetic products and uses (cooking, DIY, etc.).

The better the insulation, the higher the containment of the building."

The confinement and lack of renewal of indoor air creates the conditions for an accumulation of pollution at levels dangerous to the health of the occupants.

From a technical point of view, households have the reflex to start with insulation but they forget about ventilation. Ventilation is clearly the poor relation of energy renovation whereas it is a key item having an impact on the comfort but also on the health of the occupants - Source ADEME

Consequently, it is necessary to think about improving the ventilation of the building at the same time as the insulation or energy renovation project. The options for improving air renewal are numerous: manual ventilation, natural ventilation, single mechanical ventilation, double flow…

Studies on IAQ monitoring in buildings undergoing energy retrofits indicate a higher occurrence of moisture problems with the risk of mould growth.

Why can renovation or decoration work degrade indoor air quality?

The use, by individuals as well as professionals, of multiple materials emitting indoor air pollutants from renovation or decoration work can have a negative impact on Indoor Air Quality.

Renovation and decoration materials are a major source of indoor air pollution. Indeed, they contain many chemicals that are harmful to humans. The emission of these substances is very high for several months after their use.

In France, since 2012, there has been mandatory labelling of construction, renovation and decoration materials (insulation, glues, paints, varnishes and stains, floor coatings, stripping solutions, etc.) which indicates their level of pollutant emissions. They are classified according to the level of emissions from A+ (very low emissions) to C (high emissions).

It is advisable to use class A+ products. Be careful, however, even materials classified A+ emit pollutants.

Materials must be stored in a dry and ventilated place away from living rooms, as there is a risk of polluting living rooms.

What are the possible health effects of indoor air pollution?

  • Asthma and allergies
  • Intoxications
  • Pneumopathy
  • Neurotoxics
  • Hepatotoxic
  • Mutagens
  • Immunosuppressants
  • Endocrine disruptors


Indoor air quality testing is urgently needed if odors persist or if occupants have symptoms such as headaches, worsening asthma or allergies.

How to assess indoor air quality after insulation and renovation work?

At least 1 month after the end of the work, it is important to check whether the quality of the indoor air is degraded by the excessive presence of Volatile Organic Compounds (VOCs) such as benzene and formaldehyde classified as carcinogenic to humans.

After insulation work, it is also recommended to test for the presence of mold.