Quebec · Energy · checked September 28, 2026

Ventilation and humidity assessments in Longueuil

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 Longueuil → 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

16%

Houses built before 1961

21%

Winter design temperature

−23.2°C

How Longueuil is built

Longueuil's houses by when they were built Ten house shapes, one for each tenth of Longueuil's 52,710 houses. Before 1961: 21%, 1961–1990: 55%, 1991–2000: 9%, 2001 or later: 16%. Older houses glow hotter.
  • Before 1961 21%
  • 1961–1990 55%
  • 1991–2000 9%
  • 2001 or later 16%
Each house stands for one in ten of Longueuil's 52,710 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. Snowfall scales with heating degree-days. Sources: Statistics Canada 2021 Census (table 98-10-0233-01), NRCan HOT2000 climate data.

Why Longueuil homes get humidity problems

Longueuil gets about 4,275 heating degree-days a year and has a winter design temperature of −23.2°C, according to NRCan's HOT2000 climate data for Montréal-St-Hubert. On Longueuil'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 Longueuil's 52,710 houses (single-detached, semi-detached, row houses and duplexes), 21% were built before 1961 and 76% before 1991, according to the 2021 Census. Newer houses (16% of Longueuil'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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NRCan-licensed service organizations serving Longueuil

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

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.

Programs in Longueuil

Provincial · needs an evaluation Rénoclimat (Quebec) Quebec's audit-linked path: an assigned evaluator for $150 + tax (refunded except the tax when you receive assistance), then rebates for insulation, air sealing, doors and windows Open

Ventilation and humidity assessment in Longueuil: 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 Longueuil?

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

Ventilation and humidity assessment near Longueuil

Ventilation and humidity assessment in Montréal14 kmVentilation and humidity assessment in Laval23 kmVentilation and humidity assessment in Saint-Jean-sur-Richelieu26 kmVentilation and humidity assessment in Terrebonne28 kmVentilation and humidity assessment in Trois-Rivières115 km All 70 cities →

Sources

Checked September 28, 2026. Census figures are for the municipality (Quebec); climate data is NRCan's HOT2000 station Montréal-St-Hubert (3 km away).

Get matched with a registered advisor in Longueuil

Tell us your postal code and what you’re planning. We’ll connect you with one licensed service organization serving your area. No spam, no shared lead lists.

Email us what you’re planning, your postal code and the type of building (a house, a duplex or triplex, or a larger multi-unit building) — we’ll reply with registered service organizations for your area and which rebates apply.

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