Time to vent

What proper ventilation can do for you and your energy bill

BY JAMES DULLEY

Dear Jim: My family likes to be cool during the summer, but I worry about the electric bill. Are there any ways to use ventilation to stay comfortable without running the air conditioner as much? -- Michael A., Ellijay

Dear Michael: Proper ventilation can keep you feeling cooler and reduce your electric bills for air conditioning. The actual air temperature in your home is not really important. What is important is how you feel.

Setting your central air-conditioner thermostat just two degrees higher can reduce your cooling costs by up to 5 percent. Moving air can feel degrees cooler than still air at the same temperature. This is partially due to more heat being transferred from your skin to moving air. Also, as air flows over your skin, moisture evaporates, and this feels cooler.

There are two types of ventilation. One is moving indoor air throughout your house with the windows closed. In addition to making you feel cooler, it can balance out the room temperatures in your house. The other type of ventilation is bringing in outdoor air and shutting off the central air conditioning.

Installing a ceiling paddle fan is what is commonly thought of as indoor ventilation and it works well. Run the ceiling fan on medium or high speed with the air blowing down to create a direct breeze on your skin. During winter, reverse the blade rotation and run it on low speed. This will gently circulate the air around the room without creating a breeze. Installing a whole-house ventilation fan is a typical method for outdoor air ventilation.

Although running an electric fan can make you feel cooler, it will not cool the room. Instead, it actually heats the room air because the electricity it uses ends up as heat energy. When no one is in a room to take advantage of the breeze, always switch off any electric fan, including ceiling fans. Each kilowatt-hour of electricity used by a fan produces 3,414 btu of heat that your central air conditioner has to remove.

Small, personal fans can be very effective to create a breeze directly on you while you sit in a chair or work at one location. If you purchase a small fan, select one that can also be used as a space heater. This will allow you to set your furnace thermostat lower and save energy during winter.

New small, personal fans are available that do not have a protective cage over the blades. The blade material is soft and will not harm your skin if you bump it while it is running. By not having a cage that creates resistance, the air flow is more efficient. The blades are also easier to clean. Clean blades flow more air with less electricity usage. The old oscillating fans on a tall stand are still effective for large areas.

Setting your central air-conditioner blower to "on" can help balance out room temperatures, but it will not create much of a cooling breeze. Standard blower motors are very powerful, and running one continuously will heat up the air. Variable-speed ECM (electronic commutated motor) blower motors use much less electricity on continuous low speed, so running the blower makes more sense if your system has one.

Natural outdoor ventilation is effective and free. An effective tip is when you open double-hung windows or an entry door with a storm/screen door, open both the top and bottom sashes a little. This creates a natural vertical air flow, even on a still day.

Sit by a window on the windward side and on the first floor if you have a two-story home. Open the window just a little. Open the windows much wider on the other side or on the second floor. This will create a higher velocity of the incoming air for a stronger breeze. Build a solar chimney, an apparatus for harnessing solar energy by convection of heated air, on the sunny side of your house. This will create a natural upward draft and draw air throughout your home.

The following companies offer air-ventilation products: Holmes Products, (800) 284-3267, www.holmesproducts.com; Hunter, (888) 830-1326, www.hunterfan.com; Kaz, (800) 332-1110, www.kaz.com; Vornado, (800) 234-0604, www.vornado.com; and Winchaser Products, (800) 405-2943, www.windchaserproducts.com.

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