Bath Fans

With a functional bathroom fan, you can prevent:

• Mold and mildew
• Damp spots on the walls / ceiling
• Condensation / frost on windows
• Peeling paint on the walls

What size bathroom fan do I need?

The size of your bathroom affects the size of the fan needed to expel moisture.

Fans are rated by CFMs and sones. CFM stands for cubic feet per minute – it’s a measure of airflow. The size of your bathroom can help determine how many CFMs you need. Some manufacturers recommend the number of CFMS based on square feet or cubic feet.

Some manufacturers use the CFM formula below:

Length x Width x Height x .13 = Number of CFMs (round up to nearest 10)

For example, 8.5 feet x 9.5 feet x 8 feet x .13 = 83.98 (round up to 90)

Choose a fan 90 CFM or larger.

If you’re not interested in doing the math, small bathrooms typically require about 50 CFMs, while large bathrooms require around 100 CFMs. If your bathroom is larger than 100 square feet, add up the CFMs for each fixture below:

Toilet: 50 CFMs
Shower: 50 CFMs
Bathtub: 50 CFMs
Jet Tub: 100 CFMs

Another factor when buying a fan is sones, which is a measurement of sound. The higher the number, the louder the fan — 2 is considered quiet.

Should I hire an electrician to install my bathroom fan?

Installing a bathroom fan from scratch is complicated. You’ll need a special kind of drill, a ladder, ducts and many other specialized tools. Unless you already have all the tools and experience, you will likely pay more to DIY a bathroom fan than to hire someone.

Working with electricity is dangerous, even for experienced electricians. It is safer to hire an electrician to wire in a replacement fan or install a new one.