Q–Which would cause incandescent light bulbs to last longer: Turning them off when not in use so that the parts don’t wear out or leaving them on so they are not exposed to rapid heating and cooling?
Jessie S. Duth, Libertyville
A–Here’s a general rule of thumb about incandescent bulbs, compliments of John Katrakis of J.T. Katrakis & Associates, an energy and environmental consulting and management firm in Barrington.
The longer an incandescent bulb is on, the quicker it ages.
When an incandescent bulb is lit, the tungsten element vaporizes over time, says Katrakis.
Therefore, the less you run an incandescent bulb, the longer it should last.
“Turning it on and off should not age it, unless of course you are entering a room constantly and flicking a light switch on and off every few seconds,” says Katrakis. “That would be worse for the bulb.”
If you’re concerned about light bulb life and energy savings, consider switching over to fluorescent bulbs from incandescent bulbs.
For the same amount of light, a fluorescent bulb burns less than 40 percent of the energy used in an incandescent bulb, says Katrakis. And more importantly, it can last years longer than an incandescent bulb.
The downside is that fluorescent bulbs cost more than incandescents. That’s a major reason why people keep using incandescents. Typically, an incandescent bulb will cost around $1. A replacement fluorescent bulb can cost 10 times that. But that fluorescent bulb can last 10,000 hours, while the incandescent will last 1,000 hours. And total energy savings over the life of the bulb can be more than $50, which pays for five new fluorescent bulbs.
So long term, fluorescent lighting makes good sense. A fluorescent bulb is not only cheaper (because it lasts longer) but also saves electricity (and, as a result, money on your electric bill).
There are a couple of ways to go fluorescent.
You can change over incandescent fixtures in some areas of your home to fluorescent fixtures that take a tube-shaped bulb. Good candidates here are closet lights, basement lights or bathroom medicine chest lights.
The tube-shaped bulbs aren’t the only options. Katrakis, for example, replaced the incandescent canister lights recessed in his kitchen ceiling with canisters that take compact fluorescent bulbs.
A simpler change is to the screw-in type fluorescent bulbs that are made for use in incandescent fixtures. While you aren’t paying for replacement fixtures, these bulbs cost more than standard fluorescent bulbs so it takes longer to recoup your initial investment. However, these bulbs can be placed in living room and bedroom lamps or in overhead incandescent fixtures.
In general, Katrakis says, the best bulbs for replacement are those that are turned on more than four hours a day. The longer you run the bulb, the quicker you’ll see a return on your investment.
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Got a question about home energy or home environmental issues? Write to Energy Q&A, Chicago Tribune, Your Place section, 435 N. Michigan Ave., 4th Floor, Chicago, Ill. 60611. Or you can e-mail energy qa@aol.com. Questions will be answered only through the column.
