When selecting a ceiling exhaust fan for a bathroom or kitchen, you must ensure that the fan has the apropriate capacity to that specific room’s size and purpose. A ceiling exhaust fan must move a specific amount of air within the bathroom or kitchen to remove the moisture and odors that can build up within those areas. If the ceiling exhaust fan should be too small for the area that it is to be installed in, then the fan wont be able to efficiently clear the steam from the bathtub or the kitchen area.
With the chart that show the recommended CFM for various sizes of rooms, you can be sure that the ceiling exhaust fan that you select will be able to move enough air to allow those rooms to remain dry. Air exhaust for ceiling exhaust fans are measured in cubic feet per minute (CFM). Each room in a residence contains a specific amount of square footage, and each square footage require a specific amount of CFM for that room to remain functional.
How to Choose the Right Ceiling Exhaust Fan
The chart allows you to determine the square footage of your room and translate that into the minimum CFM that your exhaust fan should have. Additionally, the chart also shows the recommended CFM for exhaust fans to help ensure that the room will have more better performance with that particular exhaust fan. You should also ensure that the ducting for the exhaust fan have a larger diameter to allow for the exhaust fan to push the air more efficient through the room.
A narrow duct allows for more friction in the exhaust fan, which will reduce the CFM for that exhaust fan. Bathrooms often require different types of exhaust fans than kitchens. This is because bathrooms often contain high levels of moisture, especially in the area where the bathtub or shower is located.
In some bathrooms, there may be a powder room that has a small bathtub and requires a small exhaust fan. In other bathrooms, there may be a large master bathroom that has a soaking bathtub or steam shower. Soaking bathtubs and steam showers creates more moisture than a standard shower.
For this reason, the master bathroom may require an exhaust fan that has a higher CFM rating than the powder room. Additionally, charts for exhaust fans allow for the categorization of bathrooms according to their use to allow those fans to find the appropriate fan for each bathroom fixture. Should you use a ceiling exhaust fan with a low CFM rating in a room with a large bathtub, the exhaust fan will not be able to effectively remove the moisture from the room.
Kitchens require different types of exhaust fans than bathrooms. This is due to the amount of heat and grease that is created in the kitchen. It is not recommended to use exhaust fans that were created for bathrooms in a kitchen.
This is due to the fact that exhaust fans for bathrooms are not designed to handle the heat from stoves. Additionally, kitchens often use range hoods that have higher CFM ratings than bathroom exhaust fans because there is more moisture from cooking that must be removed from the kitchen. Additionally, gas ranges often create more combustion byproducts than electric stoves and ranges.
For these reasons, exhaust fans for kitchens will have higher CFM ratings to ensure proper functioning in those areas. The chart provides different recommendations for ventilation in the kitchens different than it do for bathrooms to allow users to find the appropriate fan for each of these areas in the house. Exhaust fans are not the quietest of appliances.
The noise level of ceiling exhaust fans is measured in sones. Sones represent the loudness of the exhaust fan when it is running. Fans with a rating of one sone or less are the quietest, and fans with a rating of three sones or more are loud.
If you install an exhaust fan in a bathroom that is located near bedrooms, you may want to choose a fan with a low sone rating to avoid disturbing those sleeping individual in the bedroom. Fans with DC motors tend to be quieter than fans with standard motors. Additionally, moving the motor of the exhaust fan to the attic of the house will also allow for the noise of the exhaust fan to be moved away from the bathrooms.
The installation of the exhaust fan’s ducting is essential. If the ducting for the ceiling exhaust fan is too long, too narrow, or has many elbow, the exhaust fan will not be able to effectively remove moisture from the area. If the exhaust fan ducting is made of rigid metal, it will allow the exhaust fan to effectively push air through the ducting.
Flexible tubing will allow for the ceiling exhaust fan to move less air through the ducting to the exterior of the building. Additionally, the ducting should always vent to the outside of the building. If the exhaust fan is vented into the attic of the residence, the moisture that is removed from the bathroom will condense in the attic.
Should this happen, moisture will build up in the attic and may lead to the growth of mildew in the area. Additionally, you should seal all ducting joints with foil tape to ensure that the exhaust fan does not lose any of its moving air. Foil tape creates a better seal in the joints than does standard duct tape.
When you install exhaust fans in your bathrooms or kitchens, you may want to round up to the next higher CFM rating. A ceiling exhaust fan that has a higher CFM will clear the moisture from the room faster. Additionally, if the ceiling exhaust fan does not have to run as long to clear the room of moisture, there will be less use of energy.
Additionally, a higher CFM will compensate for any loss of CFM due to friction in the exhaust fan ducting. By using the CFM chart to find the appropriate ceiling exhaust fan for each room, you will be able to ensure that your drywall and your rooms paint is protected from moisture damage.