Bathroom Exhaust Fan Buying Guide

As soothing and relaxing long, hot showers may be for you, theyโ€™re equally destructive for the interior of your home โ€” if, of course, you do not have a bathroom ventilation fan.

The high humidity levels in the compact bathroom space can provide a breeding ground for mold and mildew. This damages several functional parts of your bathroom, including wood framing and drywall.

With a bathroom exhaust fan, excess humidity and foul smells are expelled from the space, keeping it fresh and clean. Exhaust fans are so essential that they are usually a part of building codes.

Before choosing a bathroom fan, itโ€™s important to consider a number of factors, including the floor space of the bathroom and the features you require. Dive into this article for the ultimate exhaust fan buying guide, so you can choose a bathroom exhaust fan that perfectly fits your needs!

Understand Bathroom Exhaust Fan Sizing

The amount of air bathroom exhaust fans can move (or expel) is measured in cubic feet per minute (CFM). Each fan has its own value of CFM, and the sizes for these depend on this value. So, an exhaust fan with a higher CFM will be more powerful than a fan with a lower value.

Generally, you need 1 CFM per square foot of bathroom area. So, if your bathroom space occupies 100 square feet, a vent fan rated at 100 CFM will do the trick.

How To Find The The Right Bathroom Ventilation Fan Size

  1. Measure, in feet, the length of your bathroom interior
  2. Measure, in feet, the width of your bathroom interior
  3. Apply the formula: length x width
  4. The calculation area is equal to the CFM rating to look for in your bathroom exhaust fan.

For example, if your bathroom is 12 feet long and 8 feet wide, multiplying the two dimensions will give you 96. And so, you need a bathroom exhaust fan that is rated at least 96 CFM. It is generally recommended to oversize a little bit. So, in our example, you would do good with a 100 CFM vent fan.

It is helpful to remember that the minimum size for a bathroom exhaust fan is 50 CFM. So if your bathroom is, say, 6 feet x 6 feet (and the requirement is 36 CFM), youโ€™ll still have to purchase a 50 CFM fan. Bigger is only better, though!

Bathroom Exhaust Fan Sizing For Large Bathrooms

If your bathroom is larger than a hundred square feet, we recommend purchasing an exhaust fan based on the individual units in the bathroom. These will be:

  • 50 CFM for each toilet
  • 50 CFM for each bathtub, shower, and bathtub-shower combo
  • 100 CFM for each jetted bathtub and whirlpool

For example: If your 120-square feet bathroom has one shower, one toilet, and one bathtub, you will need a vent fan rated at 150 CFM. If you also add a whirlpool, this will increase to 250 CFM. For the latter, this can be divided into two (or more) exhaust fans with ratings that sum up to 250.

bathroom exhaust fan guide

Consider The Noise Level You Can Tolerate

In addition to CFM ratings, bathroom exhaust fans come with โ€˜sone ratingsโ€™. These depict the noise level (degree of loudness) produced by the fan. Generally, lower sone ratings mean quieter fans.

A sone rating of 1 equates to an exceptionally quiet exhaust fan (excellent for bathrooms where you like to enjoy relaxing baths), ratings of 2 to 4 are considered good, while exhaust fans with sone ratings of 4 or more produce considerable noise.

Pay Attention To The Efficiency of the Bathroom Ventilation Fan

In todayโ€™s era, energy efficiency is a must to consider. Usually, the motors used in exhaust fans for incredibly low noise levels also promote energy efficiency. This means quiet bathroom ventilation fans consume lesser energy than other types.

Additionally, multiple models have humidity sensors. This means the fan turns on when moisture rises above a predefined level and switches off when the levels are back to normal. Others have motion sensors, switching the fan on when someone walks in and turning it off when they walk out. Both of these may be an initial investment, but they help conserve energy in the long run.

Know Additional Features For Your Bathroom Exhaust Fan

Bathroom ventilation fans also provide a plethora of other features! Many models have integrated lights that can replace (or add on to) existing lighting fixtures. Others have built-in heaters that help keep the bathroom interior warm in cold climates. If youโ€™re searching for a bathroom ventilation fan with multiple functions, you are likely to receive a control as well (for controlling each function) in addition to the regular wall switch.

bathroom exhaust fan with remote control

Tips For Choosing A Bathroom Exhaust Fan

  • If your bathroom space has alcoves or separate areas for wardrobes or other cabinetry, you should consider purchasing more than one fan.
  • The associated duct size should be compatible with the exhaust fanโ€™s rating. Generally, a 4-inch duct does well with a 50 CFM fan, but as the fan size increases, the duct should be larger as well. This is because less air will be expelled through smaller ducts, resulting in a poorly-ventilated bathroom interior.

Final Words

In a nutshell, you are to consider your bathroom size (and associated CFM rating), noise levels, and additional features you require while purchasing a bathroom exhaust fan. While searching for your fan, you will notice certain types can be installed on the wall instead of the ceiling, too! These are suitable for expelling air outdoors (and not into the attic or room above).

Keeping the aforementioned factors and tips in mind, you can ensure excellent bathroom ventilation โ€” and protection of other bathroom features โ€” in no time!

Find more information about Bathroom Remodeling in the Bathroom section of our BLOG.