Proper bathroom ventilation ensures that stale air and excess humidity is expelled. By using fans in your bathrooms and laundry room you can reduce the risk of mould and damage to your home’s structure.
High performance and quieter than ever, today’s bathroom fans are available in various sizes, with or without light fixtures, high or low-capacity, and with manual or automatic controls. Installing a fan will guarantee a healthier environment in your bathroom, and you’ll be complying with Building Code recommendations.
All new renovations must include a ventilation system that complies with requirements in the National Building Code.
Bathroom fans are considered to be air extractors. They evacuate moisture and stale air to the outside without bringing outside air in. They are very efficient when sized properly for a specific room. Ideally, every bathroom and laundry room should have a fan.
A fan’s effectiveness is measured in its ability to expel odours and moisture generated by use of the toilet, shower and bath.
There are two main categories of bathroom ceiling fan installation:
All bathroom ventilation systems operate with either a propeller or turbine fan.
The bathroom ventilation system includes a fan and an exhaust duct to the outside. Each of these components plays an important role.
All fans are equipped with electric motors chosen according to their ventilation capacity; this capacity is expressed in cubic feet per minute (CFM). The size of your bathroom and length of ducting required will determine the capacity you should select. The type of duct you use will slightly affect your calculations, since rigid ducts require less power than flexible ducts.
Before you purchase a fan, determine the power you need to effectively ventilate your bathroom. There is a simple rule to follow: calculate 1 cu.ft./min for each sq.ft of surface area. We recommend you add a 20% margin, and add 1 cu.ft./min for each linear foot of rigid ducts and 2 cu.ft/min for flexible ducts.
For example: a bathroom measuring 10'x10' ventilated through a 6' flexible duct will require a fan capable of generating 100 cu.ft./min (10x10) plus 20 cu./ft./min (20% of 100) plus 12 cu.ft./min (6 x 2), for a total of 132 cu.ft./min of ventilation volume
A smaller bathroom will require a fan capable of generating ventilation volume of at least 50 cu.ft./min.
If you have a whirlpool bath or multi-jet shower in your bathroom, you should have a fan capable of generating at least 250 cu.ft./min of ventilation volume, because the increased movement of hot water will produces a lot of moisture in the air.
Ventilation ducts can be either flexible or rigid. Flexible ducts are recommended for distances less than 16'. They are also adaptable and can be navigated through any number of obstacles. Opt for insulated flexible ducts. Rigid ducts require duct elbows to circumnavigate obstacles. However, their smooth surface facilitates air circulation which is why they are recommended for longer distances
Keep in mind: shorter ducts mean better air circulation and reduced power requirements. We recommend using ducts that are at least 4" in diameter. Longer ducts should be 6" in diameter which will facilitate the movement of air. Smaller ducts, 3" in diameter, are not recommended.
Noise level is an important consideration. Fan noise is measured in sones, and bathroom fans are assessed when they are operating at maximum capacity. The higher the sone rating, the louder the fan. Fans noise varies from less than 1 sone to 4 sones. Just to compare, the noise produced by a relatively quiet refrigerator is equivalent to approximately 1 sone. A fan with a noise level of 2 sones is considered silent.
Activation and operation
Fans can be activated by a standard switch, timer, motion sensor or humidity sensor.
Check the space you have available before you select a fan. Because the fan is usually secured to the attic frame or to the ceiling, ceiling height may be a factor for a ground floor or basement bathroom.
Fans with integrated lighting are very practical in small bathrooms. You can also find fans that include a heat lamp, which can be very welcome when you step out of the bath or shower. Some models offer low-wattage night lights, which is useful for the children’s bathroom.
Grille or protective cover
The grille is usually made of plastic and can be square, rectangular or circular in shape. It fastens to the housing and can be removed to facilitate installation and maintenance.
Never vent to the attic; always vent to the outside. Heat and moisture will produce rot and mould in materials such as wood and insulation.
When you are determining the location of the fan, take into account that the housing must be solidly secured to floor joists in the attic. Fans are typically installed on the ceiling in the middle of the room, or depending on the model, directly above the shower or bathtub with a ground fault circuit interrupter (GFCI protected). The fan can also be installed on the bathroom wall; this type of installation is less effective since heat and moisture rises. If the toilet is located in an enclosed space, you should also consider installing a fan there.
Ductwork is concealed in the ceiling, attic or crawlspace and vented to the outside. Ductwork must be installed lying horizontally, sloping downwards slightly so that any accumulated water can easily drain out if condensation occurs. Ductwork that runs through an unheated space in the house should be insulated. You want to properly insulate your ventilation system and apply caulk where necessary to guard against heat loss. Check the placement of your ducting before you determine the final location of the fan. If your fan installation is part of a renovation project, existing plumbing and electrical work may influence the path the ducting needs to follow.
Unless you are very experienced in electrical work, it is highly recommended that you call upon a master electrician to connect your new fan. Remember that in Quebec, all electrical installations must be carried out by a master electrician and member of the Corporation des maîtres électriciens du Québec (CMEQ).
When in operation, fans generate static electricity which leads to an accumulation of dirt and sometimes even mould on the fan and fan housing. It is important you clean your ventilation system regularly, including the fan, fan housing, exterior exhaust outlet and any other accessible components of the system.
Cleaning a bathroom fan is fairly straightforward: disconnect the power first, then lower the grille housing and remove the module. However, cleaning an inline installation with ductwork that is harder to access can be more difficult.