Bathroom Exhaust Fans

Bathroom Exhaust Fans

Most people enjoy taking long hot showers.  But let me ask you a question.  Has your bathroom ever looked like it was going to rain after you did?

While that steamy environment might help to keep you warm in the cold winter, it is going to wreak havoc with your walls.

If you do not have sufficient insulation in your walls or ceiling, that warm steam will condense on the cold surfaces.  The constant dampness could cause your walls to start crumbling.

In addition, that warm, moist environment will promote mold and mildew growth.

And finally, the moisture will interact with anything made of steel and copper, and you will end up rust and corrosion damage.

To prevent or halt these problems, you should consider installing an exhaust fan.  A exhaust fan sends the warm, moist air outdoors–if properly installed.

When shopping for an exhaust fan you need to know the cubic feet of your bathroom.

  • square feet = width x length
  • cubic feet = square feet x height of room

For example, if your bathroom is six feet by eight feet then the room is 48 square feet.  Then, if your ceiling is eight feet high, then the cubic feet of your room is 384 (48 x 8).

Now that you know the cubic feet, it’s time to shop.  You want an exhaust fan that will recycle the air about once every five minutes.  Exhaust fans are sold by advertising the cubic feet per minute (CFM) they recycle air.

Knowing that your bathroom is 384 CF, you will divide that by 5 to find out you need a fan that will recycle at least 76.8 CFM.  You can always purchase a larger fan if you really want to move the air, but the largest fan available is around 180 CFM.  Therefore, if you have a really large bathroom, you may not be able to achieve the recycling rate of 5 minutes.  One idea is to intall a second fan.

This is not a guide for installing the actual fan, but you do need to ensure that the fan is properly installed.  For tips on how to do that, be sure to read Bathroom Exhaust Fan Installation.

Posted November 5, 2018 by chris in General