Humidifiers, HRVs & Air Quality

Why indoor air quality matters in an Ontario house

For half the year, a Hamilton house is closed up and heated. Cold outdoor air holds little moisture, and once it is warmed indoors it becomes very dry, which is why winter brings static shocks, cracked skin, sore throats and gaps between hardwood boards. At the same time, a tight modern house can trap moisture from cooking and showers, cooking smells and the chemicals that come off furniture and finishes. Indoor air quality work is about fixing those problems at the furnace and the ducts, not with a room gadget.

Whole-home humidifiers

A furnace humidifier adds moisture to the warm air leaving the furnace. A bypass humidifier uses the furnace’s own air pressure; a fan-powered model has its own fan and works better with high-efficiency furnaces; a steam humidifier boils water and gives the most precise control, at a higher price. Most connect to a humidistat, ideally one that automatically lowers the target humidity as it gets colder outside.

Aim for about 30 to 40% relative humidity in winter, lower on the coldest days. Too much humidity condenses on cold windows and can cause mould in walls and attics. A good installer sets the control with that in mind, and the pad or water panel should be replaced every season.

HRVs and ERVs: fresh air

A heat recovery ventilator (HRV) pulls stale air from kitchens and bathrooms and exhausts it outside, while bringing in the same amount of fresh outdoor air. The two streams pass each other in a core that transfers most of the heat, so you get fresh air without throwing away the heat you paid for. An energy recovery ventilator (ERV) also moves some moisture, which suits homes that run very dry in winter or humid in summer.

New houses built under recent Ontario Building Code rules generally have mechanical ventilation, often an HRV. Older homes that have had air sealing, new windows and new insulation can become stuffy and humid, and adding an HRV fixes that. HRVs need their filters cleaned and core washed every few months, and a yearly balance check.

Filters and air cleaners

• 1-inch filters: the default slot on most furnaces. Fine for protecting the furnace, but they catch little fine dust and clog quickly.
• Media filter cabinets: a 4- or 5-inch-deep pleated filter that catches far more fine particles, with less airflow restriction, and lasts six to twelve months.
• HEPA bypass units: a separate filter cabinet for homes with severe allergies.
• UV lights: mounted at the indoor coil to keep it free of mould and bacterial growth, which helps the AC work efficiently.
• Electronic air cleaners: effective on fine particles, but need regular washing.

Any upgrade has to suit the furnace blower. A very restrictive filter in a furnace that cannot push through it reduces airflow and can make the furnace overheat. Our guide on how often to change a furnace filter explains MERV ratings.

Smart thermostats

A smart thermostat makes schedules easy, lets you adjust from your phone, and, with a heat pump or hybrid system, can manage when the furnace takes over. Some qualify for small rebates through Ontario programs or utility offers. It must be compatible with the system: heat pumps, two-stage furnaces and humidifiers need the right wiring and settings.

Moisture problems in basements

Damp basements in summer are common in older Hamilton houses and on the clay soils south of the Mountain. Running the air conditioner helps upstairs, but a basement often needs a dehumidifier or better air circulation. A contractor can advise whether a whole-home dehumidifier makes sense or whether the problem is water getting in from outside.

Carbon monoxide

Air quality work is a good moment to check your carbon monoxide alarms. Ontario requires a working CO alarm outside every sleeping area in homes with a fuel-burning appliance, a fireplace or an attached garage. Alarms wear out, usually after seven to ten years: check the date on the back.

How the request works

You request air quality work once, and we pass it to one licensed contractor who works your area. Describe what bothers you, dry air, stuffiness, dust, odours or condensation on windows, and the age of the furnace. Pairing it with a furnace tune-up or duct cleaning saves a second visit.