Quebec · Energy · checked September 28, 2026

Ventilation and humidity assessments in Lévis

Condensation on windows, musty basements and stuffy bedrooms are ventilation and humidity problems, and they're easy to confuse with insulation problems. A ventilation assessment measures which one you have.

Get matched in Lévis → The ventilation and humidity assessment
A heat recovery ventilator on a basement wall with four insulated ducts running up between the joists

Cost

Part of an evaluation

Houses built since 2001

26%

Tighter houses that usually rely on an HRV or ERV

Houses built before 1961

14%

Older houses usually leak more and have less insulation

Winter design temperature

−24.8°C

Colder days mean more window condensation

How Lévis is built

Lévis's houses by when they were built Ten house shapes, one for each tenth of Lévis's 45,165 houses. Before 1961: 14%, 1961–1990: 46%, 1991–2000: 13%, 2001 or later: 26%. Older houses glow hotter.
  • Before 1961 14%
  • 1961–1990 46%
  • 1991–2000 13%
  • 2001 or later 26%
Each house stands for one in ten of Lévis's 45,165 houses (single-detached, semi-detached, row and duplex), drawn by when it was built. The glow shows the usual pattern: older houses tend to be leakier and less insulated. More snow in the drawing means more heating degree-days: a longer, colder heating season. Sources: Statistics Canada 2021 Census (table 98-10-0233-01), NRCan HOT2000 climate data.

Why Lévis homes get humidity problems

Lévis gets about 4,754 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 −24.8°C. Those figures come from the climate data for Ste-Foy in HOT2000, the home-energy software Natural Resources Canada (NRCan) gives energy advisors. On Lévis'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 Lévis's 45,165 houses (single-detached, semi-detached, row houses and duplexes), 14% were built before 1961 and 60% before 1991, according to the 2021 Census. Newer houses (26% of Lévis'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.

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.

The ventilation and humidity assessment in detail.

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Very Cold East Northern Ontario, Saguenay, Quebec City

What this means in Lévis’s climate

Deep, snowy winters: stop ice dams, and pair a cold-climate heat pump with backup heat.

Winters here are long and deep, with cold snaps of −25°C to −31°C and the heaviest snow loads of any region we cover. Heat escaping into the attic melts roof snow from below, which refreezes as ice dams. An EnerGuide evaluation here should focus on the attic, the basement and rim joists, and a heating plan with reliable backup heat.

  • Ventilate and keep humidity in check. Winter air is very dry, but humidifying too much frosts windows and wets the attic. Balanced ventilation keeps a tighter house fresh without adding moisture problems. Ask: Ask for a ventilation assessment and the indoor relative humidity your windows can handle in deep cold.

What else homes in Lévis need →

Sources for this climate guide · checked October 26, 2026

NRCan-licensed service organizations serving Lévis

In Quebec, EnerGuide evaluations for existing homes run through the provincial Rénoclimat program; the organizations below are the ones NRCan lists for Lévis 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.

Source: NRCan list of licensed service organizations, checked September 28, 2026. Call to confirm your street is covered and ask about wait times.

Ventilation and humidity assessment in Lévis: 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 Lévis?

Advisors assess ventilation and humidity during the evaluation; HRV or ERV sizing may be an extra service.

Ventilation and humidity assessment near Lévis

Ventilation and humidity assessment in Québec City13 kmVentilation and humidity assessment in Trois-Rivières112 kmVentilation and humidity assessment in Sherbrooke157 kmVentilation and humidity assessment in Saguenay184 kmVentilation and humidity assessment in Longueuil218 km All 70 cities →

Sources

Checked September 28, 2026. Census figures are for the municipality (Quebec); climate data is NRCan's HOT2000 station Ste-Foy (7 km away).

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