Ventilation - FAQ

In terms of habitable space, the heat recovery ventilator (HRV) is the type of unit that ensures better energy performance. In point of fact, the hot stale air is ejected outdoors and used to preheat the fresh air coming in through the system; therefore, less energy is used to bring inflowing air to a comfortable temperature.
 
Generally speaking, a good HRV yields between 60% and 80% of sensible heat recovery efficiency (SRE) (using hot stale air) at –25 ºC. Look for a model that meets these criteria and is certified by the Home Ventilating Institute (HVI).

For more information, consult the Office of Energy Efficiency Website.
 
For bathroom fans, range hood fans and ceiling fans, look for ENERGY STAR^® certification. This way you can use products that consume less energy and make less noise.

It is true that a residence must be well ventilated to maintain an appropriate level of humidity and ensure the health of its inhabitants.

In the past, houses were ventilated by simply opening the windows and doors and by counting the number of air movements (air infiltrations and exfiltrations) through the exterior walls. Still used in many homes, this method of ventilation known as natural ventilation is not always practical, comfortable or very economical.

For example, a residence that is naturally ventilated and has an air change per hour rating of 6 means that the total volume of air of this residence renews itself six times every hour. Imagine all the energy wasted in the winter to heat the cold air that is seeping into the house...and that doesn’t mean that the entire house is ventilated!

In an airtight home, the installation of a mechanical ventilation system helps control ventilation more adequately and improves the energy rating of the residence.

Since the mechanical system uses electricity, it is particularly important to select a ventilation system that helps recover heat and energy, such as a heat recovery ventilator (HRV) or an energy recovery ventilator (ERV).

Finally, it is important to remember that the installation of a mechanical ventilation system that sends fresh air into each habitable room through ducts is mandatory in new homes in accordance with current building standards and codes.

The optimal relative humidity of a home should be between 35% and 50%. It is within this range that air contaminants are less likely to proliferate (bacteria, viruses, mushrooms, moths, etc.) therefore helping to reduce the chances of developing health problems.

The degree of humidity tends to increase naturally with the various activities performed in the home such as cooking, baths, showers and the use of the clothes dryer. To maintain an adequate level of humidity it is necessary to use appropriate ventilation (by increasing the flow of the central ventilation systems, using bathroom fans and range hood fans) when using certain rooms or appliances.

It is advisable to adjust the settings of the ventilation system to reflect the season.

In the fall, winter and spring:

• During the cold seasons, set the dehumidistat between 35 and 50% of relative humidity. This will automatically set off the system to prevent excess humidity.
• When you are away from home, set the system to recirculation mode or to off (on the controller).
• When you are at home, set the system to 20 minutes of air exchange with outdoors – 40 minutes of recirculation or 20 minutes of air exchange with outdoors – 40 minutes off.
• When there are increased sources of pollutants (large group of persons, presence of smokers, etc.), set the HRV to high air exchange (max.) for specific periods of time.

In the summer:

Set the system to off (on the controller) and open doors and windows to ensure minimum natural ventilation.

In the summer, with an air conditioner:

• When you are away from home, set the system to recirculation mode or to off (on the controller).
• When you are at home, set the system to 20 minutes of air exchange with outdoors – 40 minutes of recirculation or 20 minutes of air exchange with outdoors – 40 minutes off.

At all times:

Activate the control device for the bathroom when using the toilet, bath or shower.