Energy adviser: Exhaust fans move air in sealed homes

Small electric exhaust fans do a lot of work in houses, pulling moist air and heat out of bathrooms and getting rid of cooking odors in kitchens.

It is far more effective, experts say, to quickly eliminate moisture and pollutants when they are created rather than allowing them to dissipate slowly inside your home.

Indoor air can be five times more polluted than outdoor air.

In 1991, Washington’s energy building code regulations were updated to require better air sealing for new homes as a way to conserve energy. Any space where air can enter the home is sealed during construction to limit uncontrolled exchange of air between outdoors and indoors, giving homeowners better control of air flow. Exhaust fans are designed to work in tandem with a home’s central forced-air heating and ventilation system.

Roger Heasley, store manager at Grover’s Electric & Plumbing Supply in Vancouver, said those shopping for an exhaust fan — either in a new home or as a replacement — should keep three things in mind: How much air the unit will pull, operating noise level and price.

“Obviously, quieter and more powerful units will cost more than less expensive models,” Heasley said. “Retail prices can range from as low as $39, up to $154. The more expensive models also may feature built-in lighting.”

Electrical engineers measure air movement by cubic feet of air moved per minute, abbreviated as cfm. They use a measure called “sones” to describe the sound a fan produces. The lower the sone value, the more comfortable the listening environment.

“One sone is equivalent to the sound made by your average refrigerator,” Heasley said.

If you’re getting ready to install an exhaust fan, start by reading the manufacturer’s instructions and following safety precautions. Before working with electricity, turn off the power at the service panel. Make sure your duct work is properly fitted.

If you’re using new duct work, check for the right fit. Buy metal duct work for exhaust and use duct mastic sealant on the joints. Avoid bends and aim for a straight path. Keep duct work as short as possible.

When replacing a fan, buy the same size or one larger than the existing opening — it’s easier to expand a hole than to reduce it. If you’re installing a new fan, you’ll need to cut a hole in the ceiling. But you can make installation a breeze by replacing an existing ceiling light fixture with a fan-light combo.

How to Choose the Best Exhaust Fan for Your Bathroom

All homes must have exhaust fans installed. These units serve the purpose of ensuring proper air circulation and ventilation in the home is achieved, as well as the removal of odors. Another purpose for these fans is to remove moisture inside the house to decrease humidity and to prevent the formation of molds. An exhaust fan that is properly installed will really improve the health condition of the house.

The kitchen and the bathroom are the two rooms that need an exhaust fan the most. The kind of exhaust system for each room will differ as these rooms are also used for different functions. What shall be discussed further are the features worth considering for bathroom exhaust fans in particular.

1. The Size of the Room

Most fans will work for standard-sized bathrooms. Obviously, for bigger-sized bathrooms, you would also require larger fan units.

Compact bathrooms may encourage you to go for those units that come with a light fixture or heater attached. Since you lack space, these units will really benefit you. Go for those units that will let you use bulbs with low wattage so that you can lessen your electricity utility bills.

2. Noise Element

A lot of people would prefer not to use an exhaust fan because the noise bothers them. Thankfully, the newer bathroom exhaust fans have addressed this concern and are much quieter. Choose the one that generates the least noise, and these units will display this feature with an HVI certification.

3. Timer-Enabled

This is good for those exhaust fans with a light or a heating capacity. Leaving the room will usually lead you to turn off the lights or heating even though there is still some moisture or odor lingering in the air. Having a control device incorporated into the system can help you time a delayed switch-off of your fan unit. Some units have it pre-programmed, while others can be easily programmed to your preference. With these points in mind, buying bathroom exhaust fans will become easier from now on.

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