Do you use your bathroom exhaust fan for anything other than removing odors? Believe it or not, the purpose of your bathroom exhaust fan is to remove moisture from the room. Turning your bathroom exhaust fan on during a shower or steamy bath is common sense. However, turning it off right after showering means your fan is only partially effective. According to the HVI (Home Ventilating Institute), for a bathroom to be adequately ventilated, it needs to undergo approximately 8 air changes per hour. They recommend 2-3 air changes or running the exhaust fan during and for 20 minutes after showering to remove all the steam in the room as well as water vapor that may accumulate on mirrors and walls. Additionally, it will also improve air quality, reducing damage to the home from mold, cracked or peeling paint/wallpaper, warping of cabinets, and sagging framing which saves costly repairs.
The importance of bathroom exhaust fans and when to use them
Most people switch on the exhaust fan right before entering the shower and then immediately switch it off, however steam is generated faster than it is exhausted. Furthermore, if there is moisture on the walls or other surfaces such as mirrors, this moisture can evaporate into the air after you shower. It may not look like clouds of steam, but it is detrimental to your bathroom. Running the exhaust fan for 20 minutes longer than showering allows the moisture to be eliminated. The use of a bathroom fan timer switch helps ensure that your exhaust fan runs the optimal time.
Per the International Residential Code, exhausting bathroom air anywhere other than outside of the house is not recommended. This requires the use of varying lengths of ducting. Turning the exhaust fan on creates enough pressure to move the air along the duct and out of the house. If you turn the fan off prematurely, the moist air remains in the ducts and doesn’t get completely exhausted or may take longer to exit the ductwork. Over time, this can result in issues like rust or mold inside the ventilation system. This can compromise indoor air quality and put your family’s health at risk.
How to select the right exhaust fan for your bathroom
- The size of the room is one consideration to ensure air is moving the recommended 8 changes per hour. This is based on the CFM (cubic feet per minute) of the bathroom, which works out to be one CFM per square foot of bathroom. For example, a 7’ by 10’ bathroom requires a 70 CFM fan. Additional considerations include if a separate toilet room has its own fan, where the fan is installed, and if the bathroom has ceilings higher than 8’.
- How loud the fan is. The noise level is measured in sones, with a higher number of sones being louder. The HVI recommends a level of 1.0 sones or less, though several fans rate as low as .03 sones.
- Features of the fan – One option is a light/fan; a light with a fan built in, or the alternative is a can light with a fan. You can also consider an exhaust fan with an accessory heater to keep you warm after showering. Some fans have built in night lights or are motion activated for nighttime use of the bathroom. Humidity sensing fans have also grown in popularity as they sense the rise in humidity and automatically turn off after a programmed time.
- Style of fan – Exhaust fans vary in style from contemporary (slim, sleek, and streamlined) to traditional, so don’t think all bathroom exhaust fans look the same. You have the option of picking a fan that matches the style of your bathroom.
And finally, you need to clean your bathroom exhaust fan at least every 6 months to ensure it is efficient and not a fire hazard. Before choosing a bathroom fan, make sure it’s one that will be adequate for the size of your bathroom and prioritize your wants and needs regarding noise level and the features for maximum satisfaction.