Humidity: the 12 billion euros that the French lose every year
Inflated energy bills, medical costs, real estate depreciation, emergency repairs... Humidity costs French households a fortune. Investigation into an invisible economic scourge.
12.4 billion euros. This is the estimated cost of humidity for French households each year, according to our calculations based on data from INSEE, ADEME and Santé Publique France. A staggering figure that represents €440 per household on average, but which can reach several thousand euros for the most affected housing units.
The 4 financial pits of humidity
1. Energy overconsumption: +25% on the bill
A damp wall loses up to 50% of its insulating capacity. Result: the heating runs more to compensate. ADEME estimates that humidity increases the energy bill by 15 to 25% in the affected dwellings.
Average impact per household:
+280 to 450 €/year
On an average bill of €1,800
2. Health costs: the invisible cost
Asthma, allergies, respiratory infections... Mold increases by 40% the risk of respiratory diseases according to the WHO. Consultations, medications, sick leave: the bill gets heavier.
Estimated health cost:
3.2 billion €/year
Source: Santé Publique France
3. Real estate devaluation: -10 to 20%
A property showing signs of humidity sells for 10 to 20% less. With a DPE degraded by humidity, some housing even becomes unsellable or unrentable.
Average loss on resale:
-15,000 to 40,000 €
For a property of €200,000
4. Repair work: the snowball effect
Ignoring humidity is expensive. Simple untreated condensation can evolve into dry rot (30,000 to 100,000 € of work). The longer one waits, the more the bill explodes.
Early treatment
500 - 3,000 €
Late treatment
10,000 - 50,000 €
"€47,000 gone up in smoke because of humidity"
François, 58, owner in Brittany:
"For 10 years, I ignored the spots in the basement, telling myself that 'it was normal in Brittany'. When I wanted to sell, the diagnosis revealed massive rising damp and the onset of dry rot. I had to do €32,000 of work before being able to put it on the market, and I still sold for €15,000 under the market price.
If I had acted at the first signs, I would have paid €2,000 or €3,000 maximum."
Act now to save tomorrow
The calculation is simple
- A professional diagnosis costs €100 to €300
- Early treatment: €500 to €3,000
- Savings over 10 years: €5,000 to €50,000
Take the first step
Get a free diagnosis and discover the solutions adapted to your situation.
Find an expert near meSources et références
Cet article s'appuie sur des sources officielles et vérifiées pour garantir la fiabilité des informations.
- [1]Housing quality study 2026— Qualitel
- [2]Annual report on sub-standard housing— Fondation Abbé Pierre
- [3]France housing survey— INSEE
- [4]Health costs of inadequate housing— Santé Publique France
- [5]
Rédaction ZeroHumi
Équipe éditoriale ZeroHumi
Documentation technique vérifiée à partir des sources citées (ADEME, ANSES, OMS, CSTB, CEREMA)