Did you know?

The most common cause of draft at a window or door is the movement of air across the cold surface of the interior face of the window or door. When warm air from the room comes in contact with the cooler surface of a window, it cools, becomes denser and falls toward the bottom of the window or wall. This downward movement of air is often mistaken for air leakage. These drafts are most easily corrected by warming up the surface of the window by ensuring a heat duct is located underneath it. It is important not to block or divert heat from these heat registers.

Ventilation in the home serves three major purposes:

  • To ensure there is fresh air for residents of the home;
  • To remove odours, excess humidity and pollutants from thehouse air;
  • To provide intake air to balance air that is being exhausted out of the house. This balance is important to ensure that moisture generated in the home is not forced into the walls or that gases moving out of exhaust vents or chimneys are not pulled back into the home.

Main Sources of Household Ventilation

Windows are the simplest ventilation system in houses. Windows are effective for removing odours and moisture from kitchens and bathrooms; however, open windows are nor desirable during winter months in cold climates.

Intake Vents in houses with a forced air heating systems (furnace with ducting), bring fresh air into the house from an intake vent, located near the ground at one side of the house, each time the furnace fan runs. Kitchen and bath fans draw humidity and odours from cooking and bathing out of the house before the vapour can circulate.

Exhaust Fans in some houses is linked to the operation of a furnace fan. This provides balance between the air coming into the house and the air being exhausted out of the house. Exhaust fans and furnace exhaust fan ventilation systems require little care, other than ensuring the filters stay clean and any outdoor intake vents are clear of obstructions.

Balanced Ventilation Systems may be installed in some new homes to ensure a balanced intake and exhaust of air, airborne pollutants and moisture. These are usually box-like units that contain filters, a heat exchanger, a motor, and supply and exhaust ducting. Balanced ventilation systems are designed to warm incoming air with some of the heat that would otherwise be lost to exhaust air. The filters in these units and the screens on the intake and exhaust ducting need to be checked regularly to ensure the units function well.