Ten Expert Tips for Proper Bathroom Ventilation


Proper bathroom ventilation is the key to preventing excess moisture, which can cause mold and mildew problems, damp spots on walls and ceilings, condensation on windows and mirrors, and much more. Here are 10 ventilation tips from the experts at Broan-NuTone LLC that designers, builders and remodelers should consider for new and remodeled bath projects.

1. Select a fan with the appropriate cubic feet per minute (CFM) airflow rating. Refer to guidelines set by the Home Ventilating Institute (HVI), which are based on the bathroom’s square footage and the type and quantity of water-generating fixtures to be installed. But keep in mind that HVI recommendations are minimum specifications. More is generally better when it comes to spot ventilation, so consider installing a fan with an even higher CFM rating to remove moisture more quickly.

2. Add CFMs if duct runs are long, if they have multiple turns or if the existing duct diameter is smaller than the duct connection on the new fan and cannot be upgraded. A bath fan has to fight to overcome static pressure, and a small duct diameter and multiple duct turns increase static pressure, compromising the fan’s performance. For remodels, a 4-inch duct is recommended, but if that’s not possible, upgrade to a higher CFM fan.

3. For most applications, select a fan with a low sone value for a comfortable, quiet environment. Vent fans are rated in sones, which measure the loudness of sounds. A high-quality fan will have a sone rating of 1.0 sone or less (about the same as a modern refrigerator), with nearly silent models rated at less than 0.3 sone. (By comparison, an inexpensive fan will have a 4-sone rating.)

4. Select an ENERGY STAR®– qualified fan for energy savings and performance. ENERGY STAR sets criteria for CFMs per watt, so homeowners are guaranteed savings. Also, ENERGY STAR-rated fans have to be quiet (2 sones or less) and maintain a certain level of performance.

Because utility rates are heading upward and most bath fans are in place for at least 10 years, installing an ENERGY STAR-rated fan will be of continued importance in years to come. Furthermore, ENERGY STAR-rated fans play an important role in whole-house ventilation, when the fan may be on all the time.

5. Consider a vent fan that features supplemental lighting. More is better when it comes to lighting in the bathroom, and many new fans come with incandescent bulbs or energy-efficient compact fluorescent lamps (CFLs). For remodeling projects, a fan-only model can be replaced with a unit that sports lighting, too.

6. Install a vent fan with a nightlight feature to enhance convenience and safety. High-quality models often include sockets for nightlights, which produce a gentle glow when someone gets up during the night to go to the bathroom or take medication. This is an especially important feature for seniors and children.

7. Consider a model with heating capability for increased comfort on cold mornings. Even though the temperature may feel comfortable in the bathroom, wet bathers appreciate additional heat when they step out of the shower or bath. A fan’s heating feature also can save energy because homeowners don’t have to set the thermostat higher just for an early-morning shower.

8. Install recessed fan/light units for inconspicuous operation, and decorative models for a stylish touch. Bath fans that look like traditional recessed can lights are unassuming, and ENERGY STAR-qualified models can be installed over the shower/tub. In addition, decorative fans that look like light fixtures come in contemporary and traditional styles as well as multiple finishes.

9. Consider a humidity-sensing fan that conveniently switches on when it senses an increase in humidity and turns off automatically after a specified amount of time. This is a great solution for parents of teenagers, who take long, hot showers and forget to turn the fan on, and for multifamily development owners that are concerned about property damage from mold and mildew growth.

10. Consider a multi-speed model that can operate at lower CFM levels continuously as well as higher, spot-CFM levels. This is an important feature for whole-house ventilation applications, where the bath fan might draw out small amounts of air continuously, but can be switched over to a higher CFM level when someone takes a shower or bath.