A recessed light/vent fan was installed in this shower stall for efficient ventilation.
Courtesy of Broan
Q: My old bathroom vent fan is noisy and does not remove humidity well. Will a new fan work more quietly and efficiently? Can I install it myself?
A: With the proper selection of a new bathroom vent fan, there can be significant improvement in overall efficiency and reduced noise. Replacing a bath vent fan is not a difficult project. Some models are designed with multiple duct adapters and brackets for simple installation.
Before running out to the home-improvement store to buy a new one, though, you may be able to improve the function and lower the noise level of your old fan. Often, just a thorough cleaning of the inside, especially the blade surfaces, increases airflow and decreases noise.
To be extra safe, switch off the circuit breaker to the vent fan. Unscrew the grill and the motor-mounting screws to get full access. Clean every surface you can reach, including up into the duct as far as possible, with an alcohol wipe.
Even if the motor bearings are a little worn, cleaning may bring it back into balance and reduce airflow resistance. Another lower-cost option is to get a fan-rebuilding kit, with just a new motor and blade. This will bring the unit back to its original efficiency and sound level.
If you decide to install a new bathroom vent fan, do a little comparison shopping before you buy. The sound level of a vent fan is rated in sones and is listed on the packaging. The quietest fans are only 0.3 sones, but any under 1.0 are very quiet. At this level, you can barely hear it running. A smaller (meaning less airflow) fan is typically quieter than a large one of equal quality.
To determine what size vent fan you need, the Home Ventilating Institute (hvi.org) recommends 1.1 cfm (cubic feet per minute) of airflow for each square foot of bathroom floor area. When selecting a multispeed fan, make sure the maximum airflow rating meets this standard.
There are differences in the efficiencies of bathroom vent-fan designs. To be Energy Star-certified, a small fan must vent at least 1.4 cfm/watt-used, and a larger fan (90 cfm and larger) must be twice that efficient.
Although fan efficiency is important, the type of fan control has a much greater impact on your utility bills. If a fan runs longer than necessary, it wastes electricity and draws out excessive conditioned air.
If the fan runs too little or is too small, excess moisture builds up indoors. This can make the air conditioner run longer, affect your comfort, exacerbate allergies and damage windows and building materials.
For maximum energy savings and convenience, consider a fan that combines motion sensors, moisture-level sensors, a multispeed motor and an LED light.
With this combination of features, the fan runs for the right amount of time in any situation. If the room’s moisture level is not excessively high, the motion sensor will start the fan when you enter the bathroom, then shut off after you leave. Moisture sensors automatically switch the fan to high speed when the humidity rises rapidly during a shower and back to a quieter, low speed before shutting off.
Send questions to Energy Q&A, South Carolina Living, 808 Knox Abbott Drive, Cayce, SC 29033, email energyqa@scliving.coop or fax (803) 739-3041.
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The following companies offer bathroom venting products:
Broan/Nutone, (800) 558-1711, broan.com
Continental Fan, (800) 779-4021, continentalfan.com
Fantech, (800) 747-1762, fantech.net
Hunter, (888) 830-1326, hunterhomecomfort.com
Panasonic, (800) 405-0652, panasonic.com