After determining the fan’s location, make sure it can be positioned parallel with a joist bay and in the direction of the fan’s outlet. If the ductwork is located in an unconditioned space you may want to insulate it to prevent condensation. Consider where the termination point will be as well. These fans can be vented through the roof, a gable wall or a soffit. When locating the termination point keep in mind the direction of prevailing winds, and try to find a location that is out of sight.
Once the CFM requirement and the fan’s location are determined, you need to choose the type of fan to install. You can specify a fan-only product, a combination fan/light or a combination fan/ light/ heater. Some manufacturers even include a night light. Fan-only solutions work when you have a good lighting plan. Fan/light combinations are good solutions if you have limited ceiling space and need general lighting.
Combinations with heaters should be placed in a location where a bather is going to be naked and wet. Having so many options requires careful consideration of the number of switches required to operate all of a fan’s features.
You may need to specify a single-gang box with four switches just to operate a single unit. Fans should be switched with timers. They are most effective when left on for 20 minutes after a bather leaves the room.
Look for the Energy Star rating and an HVI certification when specifying and purchasing your products. Become familiar with all available products, and work with a manufacturer that has good representation in your community. Remember that aesthetics are just as important as efficiency.
Good bathroom ventilation protects a client’s health as well as their homes. The design/build community is responsible for specifying and providing this ventilation, so the systems we design must be balanced and easy to use. The products we choose must be visually appealing. It is our responsibility to promote healthier indoor environments along with good indoor air quality.