Do whole-house fans lower utility bills?

Q. My mortgage payment just shot up and I need to lower expenses. I was wondering if installing and using a whole-house fan, instead of the air-conditioner as much, would save much on my utility bills?

A. Depending upon its size, a whole-house fan uses only 10 to 20 percent as much electricity as a central air conditioner. Also, it uses significantly less electricity than a window air conditioner, yet it keeps the entire house more comfortable, not just one room. Installing one generally provides a good payback on the investment.

It is not difficult to install a whole-house fan yourself to save the labor costs. It is usually installed in the ceiling in a hallway so it sucks air out of your house and blows it into the attic. This also keeps the attic area cooler. You must make sure there is adequate exhaust vent area in the attic to handle the air flow.

The comfort and saving benefits of using a whole-house result from drawing cooler outdoor air throughout your home and the windchill effect of the breeze upon your skin. The indoor breeze from a properly sized whole-house fan can make you feel up to six degrees cooler than you would in still air.

The actual savings you realize depend upon your climate and your sense of comfort. If you live in a dry climate and can handle a little heat during the daytime, you might be able to get by without using your air conditioner at all. Run the fan at night to cool the house so it stays comfortable much of the day and then run a swamp cooler during the peak afternoon heat.

For more humid climates where you also air-condition, you may not want to use the whole-house as often. The cooler, but humid, air it brings indoors overnight can saturate the house with moisture. This may make the air conditioner run harder to remove the moisture the next day.

Pay attention to how long the air conditioner runs when alternated it with the whole-house and try to determine if there is a savings during the hottest weather. You electric bills will be the final proof. During all but the hottest weather though, using a whole-house fan should provide savings.

The two basic types of standard whole-house fans are a direct-drive or a belt-drive. Direct-drive fans have the fan blade mounted directly to the motor shaft so it spins the same speed as the motor. This is the least expensive design and is used on the smaller (air flow capacity) fans.

Larger fans often use a belt drive with pulleys to slow the fan speed. The motor is located at the corner or side of the frame. These often have higher-pitched blades and are quieter and more efficient. Some high-efficiency models have highly insulated covers which automatically open and close. These usually have two smaller direct-drive fans in one unit.

The following companies offer whole-house fans: Airscape, (877) 711-4822, www.airscapefans.com; Air Vent, (800) 247-8368, www.airvent.com; Marley, (843) 479-4006, www.marleymeh.com; R.E. Williams, (888) 845-6597, www.wholehousefan.com; and Triangle Engineering, (800) 255-9014, www.trianglefans.com.

Q. We recently had a new condensing furnace installed. It uses a small plastic pipe to vent outdoors. I am concerned animals may get in there. Will covering it with screen block the air flow too much? - Glenn R.

A. A screen can cause a significant resistance to air flow so do not just put screen over it. You may be able to make a funnel-shaped extension with a much larger opening. Cover this with coarse screen. Check with the furnace manufacturer.

The times of the year when most animals will make nests in there is after the heating season. You can cover the existing pipe opening with screen, but don't forget to remove it before you start to use the furnace next fall.

• Write to James Dulley at 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit www.dulley.com.

Historical timeline

1834: The Bernhard Koehler and Friedrich Graue families begin a large influx of German families moving to the area.

1840s: A steam grist mill, general store, cobblestone shop and blacksmith shop are the first businesses established.

1858: School District 4 opens with its first public school; Peter Nikel is the teacher.

1864: The first Concordia University is built in Addison, staying until 1913.

1874: Evangelical Lutheran Orphan Home opens to raise, train and educate orphans. School-aged children went to St. Paul's Christian Day School.

1884: Addison incorporates; population 400.

1902: Addison State Bank, the village's first, opens.

1920s: Gravel and concrete roads replace muddy roads and dusty trails. Two lanes of Lake Street are paved in 1922. Water system installed.

1962-1965: Public library and park district established.

1998: Army Trail Boulevard from Kennedy Drive to Lake Street is designated as Addison's historical district, which includes St. Paul Lutheran Church, Addison Century House and the Addison Historical Museum.