Busting myths on ways to conserve energy

December 16, 2007

My teenage son and I have an ongoing "discussion" about whether to turn off lights when leaving a room. He says it uses more electricity to turn them off and on than just to leave them on. I don't think that makes sense. Who is right?

This is one of the energy myths we often run into. In this case, you are right.

It's true, a small burst of power is used when a light is turned on, but it's tiny compared with the amount of energy used while it is burning. This is true of all types of light bulbs, including compact fluorescent bulbs. It's also a myth that frequently turning lights on and off reduces their operating life.

Here are some other energy myths we frequently hear from customers:

Myth No. 1: It takes more energy to warm up a room than to just maintain a comfortable temperature.

Not true, with most heating systems. When you're away for several hours and when sleeping, it pays to lower the thermostat. A one-degree decrease in temperature for eight hours equals a 1 percent to 2 percent savings on heating costs for that period.

How much you should lower a thermostat depends on the type of heating system and your personal comfort. Temperature setbacks work great with zonal systems such as wall heaters. Baseboard heaters are slower to warm up, so we advise adjusting the thermostat only a few degrees. Due to the long warm-up time, we don't recommend any setback on ceiling-cable heat. Customers with forced-air heating systems, which recover more quickly, can make larger fluctuations. We recommend installing a programmable thermostat that will adjust automatically. For heat pumps we'd recommend about a 6-degree setback.

Myth No. 2: Heat rises, so why would someone install ceiling heat?

Heat doesn't actually rise (although hot air rises unless restrained). It is radiant energy that travels from warm objects to cooler ones. Heat from your ceiling radiates down, heating objects in the line of sight of the ceiling. Those objects, in turn, heat up and radiate heat to other cooler objects and surfaces. The more insulation in the floor, walls and ceiling, and the more efficient your windows, the less heat will be lost to these cooler surfaces.

Myth No. 3: Energy Star is a gimmick to sell more appliances.

Not true. Energy Star is a program to promote the manufacture and purchase of more energy-efficient products and homes. The program, begun in 1992, encompasses thousands of products that meet energy use criteria set by the U.S. Environmental Protection Agency and the U.S. Department of Energy. Since its beginning, the program (which includes Energy Star homes) has helped Americans save about $14 billion on energy bills and prevented greenhouse gas emissions equal to those from 25 million vehicles, according to Energy Star's 2006 annual report. If you are in the market for new appliances, it makes sense to look for the Energy Star label. You'll be saving money each month in lower operating costs.

Myth No. 4: I can save 50 percent on my heating bill if I buy a more expensive space heater.

This is a myth we've written about before, but the facts are worth repeating. If heaters plug into an electrical outlet, they will:

• Be 100 percent efficient at turning electricity into heat.
• Convert one watt of electricity into 3.413 British thermal units of heat ... and no more.
• Produce more heat the higher the wattage.
• Offer a maximum wattage of 1,500, or 5,120 BTUs.

Excepting any energy used to, say, run a blower or rotate the unit, the wattage consumed by an electric space heater will create the same amount of heat regardless of its cost or other features. A $40 heater will be as efficient as a $400 heater. So shop wisely and buy the correct size of heater for your use. If manufacturers' promises sound too good to be true, they probably are.