Win Air Ultra Quiet Ventilation Fan Bathroom Exhaust Fan (70CFM/0.3Sone) with 4 Inch Duct Size

How to chose your bathroom fan:

Determine CFM:

A fan's ability to move air is measured in cubic feet per minute (CFM). The bigger your bathroom, the higher the CFM rating you'll need.

Tip: A fan should have a CFM rating high enough to replace the air in your bathroom at a rate 8 times per hour.

Most fans are rated from 50 to 110 CFM. For bathrooms 50 square feet and smaller, get a 50 CFM fan. For bathrooms that are larger, you need to select a fan that can move at least 1 CFM per square foot of room. So, for an 80 square foot bathroom, select a fan with at least an 80 CFM rating.

Determine the size of your bathroom with this formula:

Length x Width x Height x 0.13 = Minimum CFM rating

Bath Fans Sound & Ducting:

• The best bath fans have a sone rating less than 1.5. Before installation, check to see if you can use existing wiring and ducting.
• The industry standard for measuring the amount of sound a fan makes when it's in use is called sones.
• The lower the sone rating, the quieter the fan will be.
• One sone is equivalent to the sound of a quiet refrigerator. A quiet bathroom fan will be rated at about 1.5 sones or less.
• If you are replacing or upgrading a fan, the diameter of the duct connector on the new housing may be larger than the size of your existing duct. To maximize performance, try to match your duct diameter to the new fan