Ventilation allows you to keep the interior of your home comfortable and maintain good indoor air quality. It also contributes to the health of the home’s occupants.

What does ventilation allow for?
Ventilation consists mainly of regularly expelling to the outside the odours, excess humidity and pollutants contained in the ambient air of the house. It also draws in fresh air from the outside to constantly refresh the air you breathe indoors. Opening windows is not enough to ensure proper ventilation of your home. In the winter, only mechanical ventilation will work.

What are the possible problems of inadequate ventilation?
Inadequate ventilation generates excess humidity that causes condensation in the windows, premature deterioration of the house and the proliferation of mold.

If there is inadequate or faulty ventilation, there is a risk of increased concentration of chemical and biological contaminants contained in the air. For example, doing extensive repair work or home projects, stripping paint from furniture and using gas-fired equipment are all sources of pollution for the ambient air. Proper ventilation is necessary to keep indoor air free of such pollutants.

Excessive, poorly balanced ventilation or a ventilation system that is poorly maintained often causes discomfort, dries the ambient air in winter and wastes energy.

Another means of coping with contaminated indoor air is to dilute the pollutants with intakes of fresh air. The best solution, of course, is to limit the sources of indoor pollutants. Storage of paints and cleaning products is usually an easily avoidable source of contamination.

What are the points to consider when choosing ventilation equipment?

  • Determine the necessary air flows and select equipment capable of providing an air renewal rate that is sufficient, not excessive.
  • Measure the air flows and have a specialist balance air flow when the equipment is installed.
  • If possible, opt for a heat recovery unit, as it will help keep your home heating bill at an acceptable level.
  • Make sure that the unit and the ducts are accessible at all times to facilitate maintenance and regular cleaning.
  • Use rigid conduits for easy cleaning, and maintain all components in good condition.
  • Have the air tightness of your home evaluated by an expert before buying or installing a ventilation system.

What does the installation of a ventilation system entail?
The installation of a ventilation system is a necessity for almost all homes. In order for the system to be adapted to the particular conditions and needs of each house, it must be designed by ventilation professional in accordance with the 1995 National Building Code of Canada or higher standards.

The ventilation system can be simple (a central air circulator) or more elaborate (a layout of several ventilators and conduits), depending on need.

Bathrooms should be equipped with an exhaust fan and kitchen stoves or ranges with an exhaust hood to expel smoke directly outside. Living rooms, bedrooms and regularly used closed rooms should have grilles for fresh air intake.

Mechanical ventilation of your new home
Modern homes are airtight, which increases comfort level and reduces energy costs. Nonetheless, various factors that affect indoor air quality also threaten the health of its occupants. In building airtight houses, construction includes a number of composite materials, which are assembled by means of adhesives that can contain toxic substances, such as the particle board used to build kitchen cabinets and children’s furniture, not to mention the carpeting that covers most bedrooms.

The most important provision of the National Building Code concerns mechanical ventilation of new homes. In addition to the obligation to install a system capable of replacing the total volume of air in the house once every 3 hours, fresh air must also be delivered into each room of the living quarters by means of conduits. Rigid conduits provide better performance, and are also easy to clean and balance. Installation of a heat recovery unit is suggested for reasons of comfort and energy efficiency. If the house has a fuel-burning unit such as a fireplace or an oil-fired furnace, the system must be equipped with a ventilation opening for so-called makeup air. Installing a carbon monoxide (CO) detector is strongly recommended.

If makeup air enters only by infiltrations in the envelope, it is possible that the pollutants in the building materials that make up the envelope could contaminate the indoor air. The drainage system could also contribute to indoor air pollution by allowing radon to infiltrate the living quarters.

Source: Agence de l’efficacité énergétique du Québec