Bathroom and kitchen fans are an important part of your home’s ventilation system. They remove odours from your house, which improves indoor air quality. They also remove moisture, which decreases the level of humidity in your house. High humidity can damage building materials and can cause mold growth. Mold may affect your family’s health.
Common Fan and Exhaust Systems
The two most common types of fans are impeller fans and blower fans.
Impeller fans move air with blades similar to airplane propellers.
Blower fans look like hamster wheels — they are often called squirrel cages — and generally do a better job of moving air than impeller fans.
Most exhaust systems consist of an exhaust fan, ducting and an exterior hood. Some houses have a central exhaust system, in which one fan draws moisture and odours from several rooms of the house using a network of ducts.
Kitchen exhaust systems usually have the fan and fan motor in the exhaust hood. Other systems use an in-line fan, which is in the exhaust duct, or a fan outside the house. In-line and outdoor exhaust fans are usually quieter than systems with the fan in the room.
A heat recovery ventilator (HRV) also exhausts moisture and odours. An HRV is a self-contained ventilation system that provides balanced air intake and exhaust. Like a central exhaust fan, it can be connected to several rooms by ducting.
How Good Is the Fan I Have Now?
CMHC’s research shows that many houses have exhaust fans that:
- are too noisy
- move very little air
- are not energy efficient
- may cause backdrafting of combustion appliances
- use high-wattage lighting
Are There Better Fans?
Yes. There’s a new generation of effective, quiet, energy-efficient exhaust fans and controls.
How Do I Choose the Best System?
First, choose the quietest, most energy-efficient fan in the size range required. Most fan labels have Home Ventilating Institute (HVI) ratings so you can compare noise and energy efficiency. Look for a fan with replaceable parts and permanent lubrication. A fan suitable for continuous use is preferable. Be prepared to pay more for a quality fan.
Second, select low-resistance (smooth) exhaust ducting. Seal the joints and insulate sections that run through unheated spaces.
Third, place the exhaust hood where it will not cause moisture damage on exterior surfaces.
Fourth, if you have heating appliances with chimneys, make sure that fans won’t cause the appliances to backdraft.
Fifth, install the proper controls.
To read the full CMHC fact sheet, click here…