An exhaust fan’s ability to circulate air is measured by cubic feet per minute (CFM), and it’s the most important factor when it comes to choosing the right fan for your bathroom. First, you need to measure your space. The general rule is that all bathrooms should have a fan with a rating of at least 50 CFM. Bathrooms larger than 50 square feet should operate on a 1:1 ratio (one that’s 80 square feet, for example, should have a fan with at least 80 CFM). And if you want to get really precise with your measurement, you can use a simple formula to figure out the minimum CFM required for your space.





Sones
Paying attention to the sone rating of an exhaust fan is key. A sone is a measurement of sound: the fewer sones, the quieter the fan. It’s a personal preference, so before you buy one, ask yourself how quiet you’d like it to be. Low-sone exhaust fans are pricey, but more brands are making affordable models. You don’t need to buy the most expensive option, but don’t be tempted to go for the cheapest either. This should be a one-time purchase, so investing a little extra ensures you won’t have to think about it again.

Bells and whistles
When replacing or installing an exhaust fan, you have the option of stepping it up to appeal to future buyers. Spring for a model with a built-in heat lamp or night light (a bonus if you have children). There are also fans that come with timers, which eliminate having to remember to turn off the fan each time you finish using the bathroom.