Dry Winter Air in the GTA: Why It Happens & How to Fix IAQ (Humidifiers, Filtration, Ventilation)
When the heat turns on in Brampton, Mississauga, Toronto, Caledon, Oakville, Vaughn and The Greater Toronto Area, indoor air often drops into the low 20–30% humidity range. That means dry skin, static shocks, sore throats—and wood floors and furniture that shrink and creak. Here’s how to fix winter IAQ (indoor air quality) the right way.
Why homes get dry in winter
Cold outdoor air can’t hold much moisture. When it’s heated indoors, relative humidity falls.
Air leaks & ventilation move dry outdoor air in and humid indoor air out.
Furnace runtime increases air movement and evaporation.
Target winter humidity: generally 30–40% RH. If you see window condensation, dial it down a few percent.
Humidifier options (what to choose & when)
1) Bypass Humidifier (cost-effective, quiet)
Uses the furnace’s blower to push air across a water panel.
Best for: small–mid homes, continuous-fan setups
Maintenance: replace water panel 1–2×/season
2) Fan-Powered Humidifier (more output)
Built-in fan increases moisture delivery.
Best for: larger homes or tighter duct runs
Maintenance: panel replacement + annual cleaning
3) Steam Humidifier (highest control/output)
Boils water to produce sterile steam; controlled by a humidistat.
Best for: large homes, fine control, finished spaces
Maintenance: canister replacement + annual service
Pro tip: Pair any system with an outdoor temperature compensation control—humidity automatically lowers in extreme cold to prevent window condensation.
Filtration & airflow upgrades that help IAQ
Bigger filter boot / media cabinet (4–5") → lower pressure drop, better capture, happier blower.
MERV 11–13 media → catches finer particles (dust, pollen, many allergens) without choking airflow.
Sealed return/duct leaks → reduces dust infiltration and keeps humidity steadier.
Ventilation & fresh air balance (don’t over-dry)
HRV/ERV settings: Too much winter ventilation can over-dry a space. Balance runtime with IAQ needs.
Economizers (commercial): Verify minimum position so you meet code/IAQ without flushing all your moisture out.
Spot sources: Kitchen/bath fans should move moisture out when needed, but not run 24/7.
Simple homeowner checks
Replace filters on schedule (and make sure they fit—no bypass gaps).
Keep supply/return vents open; blocked vents raise static pressure and reduce humidifier performance.
Watch for condensation on windows—turn the humidistat down a few percent or increase ventilation for a short period.
Check your CO alarm and test monthly.
When to call a pro
You want whole-home humidity control tied to outdoor temperature.
You’re seeing condensation, moldy smells, or very uneven humidity by floor/zone.
You’re upgrading to high-efficiency filtration, adding a media cabinet, or integrating with a smart thermostat.
Commercial sites: you need IAQ + ventilation tuned across RTUs, economizers, and building schedules.
Ready to stop the winter static and sore throats?
Book Humidifier & IAQ Upgrades, or call 647-531-6151. For urgent heating issues, contact 24/7 Emergency HVAC.
FAQs (visible on the page)
What’s the ideal winter humidity for GTA homes?
Aim for 30–40% RH. If you see window condensation, lower it a bit.
Do humidifiers raise energy bills?
The added moisture lets you feel comfortable at a slightly lower temperature. Fan-powered/steam units use power, but comfort gains often offset costs.
How often should I change the water panel or canister?
Typically once per season for panels; steam canisters often once per heating season—depends on water quality and runtime.
Will a bigger filter help IAQ?
Yes. A 4–5" media cabinet with MERV 11–13 captures more without starving airflow—great for comfort, cleanliness, and system health.
