How Laval is built
- Before 1961 17%
- 1961–1990 50%
- 1991–2000 13%
- 2001 or later 20%
Why Laval homes get humidity problems
Laval gets about 4,167 heating degree-days a year, a measure of how much heating its climate needs, and its winter design temperature, the cold day heating systems are sized for, is −23.1°C. Those figures come from the climate data for Montréal International in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. On Laval's coldest days, window glass and poorly insulated corners get cold enough for condensation at humidity levels that feel normal indoors, so winter humidity needs to stay at the lower end of the comfortable range.
Of Laval's 101,460 houses (single-detached, semi-detached, row houses and duplexes), 17% were built before 1961 and 67% before 1991, according to the 2021 Census. Newer houses (20% of Laval's were built since 2001) are tight and usually have an HRV or ERV that needs balancing and cleaning. Older houses that get air-sealed can lose the accidental ventilation they used to rely on.
Laval's humid summers bring the opposite problem: warm, moist air condenses in cool basements. Health Canada recommends keeping indoor relative humidity between 30% and 50%; in summer that usually means a dehumidifier in the basement and an air conditioner that isn't oversized, since an HRV or ERV doesn't take moisture out of the air.
What the assessment measures
- Relative humidity in living areas and the basement.
- Actual airflow from bath and kitchen fans, and whether they vent outside rather than into the attic.
- How much fresh air the house gets, and whether an HRV or ERV is balanced.
Related tests in Laval
NRCan-licensed service organizations serving Laval
In Quebec, EnerGuide evaluations for existing homes run through the provincial Rénoclimat program; the organizations below are the ones NRCan lists for Laval postal codes.
A service organization is a company that Natural Resources Canada (NRCan) licenses to deliver EnerGuide evaluations; its registered energy advisors do the home visit. Advisors assess ventilation and humidity as part of an evaluation and check that exhaust fans actually vent outside. Sizing an HRV or ERV may be extra.
- Expertbâtiment Services-Conseils
- Expertise en batiment Champagne
- ENERGIE3R
Ventilation and humidity assessment in Laval: common questions
HRV or ERV?
Both bring in fresh air and recover heat. An ERV also transfers some moisture, which helps keep very dry winter air from getting drier; an HRV suits houses that tend to run humid.
Why did condensation appear after we got new windows?
Tighter windows cut accidental air leakage, so humidity builds up. The fix is usually controlled ventilation, not leakier windows.
Is a ventilation assessment part of an EnerGuide evaluation in Laval?
Advisors assess ventilation and humidity during the evaluation; HRV or ERV sizing may be an extra service.