Quiet Vent Fans

Q – I know it is important to run our bathroom vent fan, but I seldom switch it on because it is so noisy. We are remodeling our bathroom now. What are the best new quiet vent fans and what size is best?-Kathy J. 

A – Running a bathroom vent fan is very important for good indoor air quality (moisture, odors, and allergies). Even if your bathroom has a window that you can open, running a vent fan for the proper amount of time provides more effective ventilation year-round. Often when you crack open a window, you forget to close it until you use the bathroom again. 

  Although your old bathroom vent fan may sound like it is using a lot of electricity, fan motors are fairly low-wattage. By removing the excess moisture, especially in the summer when using air conditioning, your electric bills can be reduced overall. 

  In the winter, moisture often causes window condensation that can damage the drywall around the windows. In some instances, the moisture will migrate into the wall cavity and saturate the insulation, reducing its effectiveness. In severe situations, the insulation and wall structural materials can be destroyed. 

  For the most convenience and efficiency, consider installing a super-quiet combination vent fan/light. The premium models, usually the most decorative and full-featured, are often the most quiet models too. The newest trends are ones with beveled or frosted glass panels with brightly polished metal or real oak wood trim. They look more like decorative ceiling light fixtures because the air vent inlets are hidden in the trim ring.

  The key to efficient operation of a bathroom vent fan is knowing how long to leave it on. If you switch it off too soon, the moisture and odors are not completely re-moved. If you run it too long, it sucks out excessive conditioned indoor air. The best new models take care of this with built-in automatic humidity and/or motion sensors. 

  The humidity sensor switches on the bath vent fan and runs it only as long as necessary. It quickly clears excess moisture and then shuts off to save electricity. If the moisture level is not elevated, the motion sensor will switch on the light and the fan for only as long as you are in the bathroom.

  A model with a motion sensor and night-light is a great plus, especially with children. The 7-watt night-light uses very little electricity and often provides adequate brightness to use the bathroom at night. If you like more light, activate the motion sensor (most have manual override sensor switches) so that the bright light comes on the instant that you enter the bathroom. Some models also offer efficient fluorescent bulbs. 

  When shopping at your local home center for a bathroom vent fan, most models will look similar. To compare the sound levels-and they vary a lot-check the sound ratings in sones (usually listed on the packaging). Hidden internal features like sound-absorbing scrolls, rubber motor mounts, and shape of the air chambers have a great impact on the sound level.

  The quietest small models operate at less than 1.0 sone (the sound level of a quiet whisper). New higher-capacity models, rated in cubic feet per minute (cfm) of airflow, are typically somewhat louder, but will still be much quieter than your old one. Any models under 2.0 sones are considered quiet. 

  Since the sound level is somewhat a function of cfm capacity, it is important to size the fan properly. Also, a properly sized fan will vent the bathroom more effectively. As a rule of thumb, the airflow capacity, or cfm, of a bathroom vent fan should be about 10 percent greater than the square footage of the bathroom. For example, a 50-sq.-ft. bathroom needs a 55-cfm vent fan.