Bathroom Fans: A Complete Guide

What Does a Bathroom Fan Do? 

Depending on your climate, up to 20 percent of households might be affected by humidity issues. High humidity levels in homes can lead to several problems, both for homeowner health and the building's structural integrity. According to a recent publication by the Environmental Protection Agency (EPA), the ideal indoor relative humidity (RH) for homes should be kept between 30 and 50 percent. When humidity levels rise above 50 percent, mold and mildew growth will almost assuredly begin to grow throughout your home. While we often associate mold with growing on wood, other types of fungi can grow on paper, carpeting, food, and even your insulation when the moisture conditions are correct. Mold and mildew spores are among the leading causes of respiratory diseases, asthma, and other allergies affecting millions of people across the country. In addition, high humidity levels can create ideal conditions for pests such as cockroaches and dust mites.

What is an HVI Certified Bathroom Fan?

HVI Certification for bathroom fans ensures that the product has undergone rigorous performance testing by a third-party organization. The testing required for HVI Certification provides:

• Assurance that independent testing has been completed. 
• Confirmation the product will perform as advertised.
• The security that a properly sized and installed model will give the user the right amount of ventilation for the best indoor air quality.

Fans without HVI Certification can inflate their performance ratings and may not always meet building code requirements. HVI Certified bathroom fans are widely available from most major brands, and you can even filter for this attribute when shopping online.

Do Bathroom Fans Use a Lot of Electricity? 

As with almost every appliance and energy fixture in the home, the answer to this question is: "It depends." Just as LED light bulbs use only a fraction of the energy compared to older incandescent bulbs, bathroom fans have a wide range of electricity use. The most energy-efficient models who receive ENERGY STAR certification might use as little as 6 watts, similar to a LED light bulb. On the other hand, standard bathroom fans might use upwards of 60 to 70 watts of electricity. Some of the newer models of bathroom fans can include lighting fixtures, which will increase the overall energy usage of the product. 

What Are the Different Types of Bathroom Fans? 

Almost all bathroom fans complete the same function of getting rid of excessive odors, humidity levels, and even mold spores that accumulate in bathrooms' moist environment. However, there are slight differences based on where the fans are mounted, how they expel the moisture and air inside bathrooms, and any extra features they might include. The most common types of bathroom fans available on the market today include:

• Ceiling-mounted fans
• Wall-mounted fans
• Exterior exhaust fans
• Inline exhaust fans
• Bathroom fans that include lighting fixtures

What Is a Ceiling-Mounted Exhaust Fan?

This type of fan is best for bathrooms located on the upper stories of a home. The exhaust pipe will move up through the attic and vent to the outside through the roof. For this type of fan, it is vital to make sure that the ductwork is vented to the outside. In addition, assure that it is insulated to avoid condensation buildup that could negatively affect the insulation in your attic.

What Is a Wall-Mounted Exhaust Fan?

A wall-mounted exhaust fan is for bathrooms located next to an exterior wall. In this type of installation, the fan is set up on the outside of the outer wall. Wall-mounted exhaust fans offer power ventilation coupled with quiet operation.

What Is a Exterior Exhaust Fan?

An exterior exhaust fan is mounted on the exterior of the home. These are great for reducing noise levels inside the house while regulating moisture to prevent mold and mildew

Do Exhaust Fans Have Lights?

For homeowners who want to improve the aesthetics of their bathroom, exhaust fans that include lighting fixtures are often less of an eyesore and achieve multiple purposes in one unit.

How Do You Know If a Bathroom Fan Is Efficient?

The energy efficiency of bathroom fans is measured by airflow. The metric for measuring this airflow is in cubic feet per minute per watt (cfm/W). Unfortunately, the minimum standard for ENERGY STAR bathroom fans has an efficacy rating of only 2.8 cfm/W. The most efficient models on the market today, however, can achieve a grade of up to 19 cfm/W. If you are searching for the most energy-efficient bathroom exhaust fan for your home, don't only look for ENERGY STAR certification. Instead, check the label for the efficacy rating and prioritize products that achieve a minimum cubic foot per minute per watt rating of at least 10.

How Do You Calculate the CFM Required for a Bathroom Fan? 

Bathroom fans are rated by their cubic foot per minute (CFM) rating. This doesn't necessarily determine the product's energy efficiency as it doesn't look at per-watt usage. However, it can be helpful to size the best fan for your bathroom properly. Most fans come with a CFM rating anywhere between 50 and 110. Homeowners can adequately size the best bathroom fan for their homes by using the following formula:

How Long Do Bathroom Exhaust Fans Last? 

Bathroom fans, when properly maintained, will last for an average of ten years. Dusting and cleaning around the fan intake will help avoid the accumulation of dust and debris, which will put more stress on the fan's small motor. If your bathroom fan is noisier than usual, it might be a sign that it is wearing down and needing replacement.

Why Does a Bathroom Fan Make Noise? 

Bathroom fans make minor amounts of noise due to the small motors, fans, and blower wheels that help expel the moisture-ridden air. Most new models of bathroom fans will make minimal amounts of noise. However, homeowners who want the most silent fans should opt for exterior exhaust fans mounted on the home's exterior.

How Long Should You Run the Bathroom Fan After a Shower? 

The optimum amount of time homeowners should run the bathroom fan after a shower largely depends on the shower's length, the size of the bathroom, and whether or not the bathroom has an operable window. However, the Home Ventilation Institute recommends leaving the bathroom fan running for at least 20 minutes. This time will lower humidity levels and get rid of excessive moisture and condensation levels in the bathroom and in the ductwork that takes the moisture outside the home.

How Do You Maintain a Bathroom Fan? 

The accumulation of dust can lead to louder, vibrating noises that are not only annoying to listen to but can reduce the lifespan of your fan. Excess dust can settle on the fan blades or the blower wheel. In the worst-case scenario, this can cause the fan to hit the exhaust housing and produce a loud, banging sound. Regularly cleaning and dusting around the fan intake and the entire housing is the best way to properly maintain your bathroom fan.