Make smart changes to decrease power bill

By Alice LaPierre
Tuesday August 21, 2001

According to a 1996 Department of Energy report on residential lighting, in the average U.S. home, lighting accounts for about 1,800 kilowatt-hours a year of the total electricity bill, more than $200 annually at current energy rates.  

The smartest way to avoid the sting of high-priced energy is to make simple changes to reduce the amount of energy used for lighting.  

With compact fluorescent bulbs, it is possible to get the same amount and quality of light for a lot less money. 

U.S. Environmental Protection Agency and Department of Energy studies show that if every household switched to EnergyStar efficient light fixtures and bulbs, the savings would amount to 70 billion kwh and prevent the release of 100 billion pounds of carbon dioxide per year – the equivalent of removing 10 million cars from the road.  

These are just the environmental benefits. The consumer can reap significant economic benefits as well. 

Besides reducing your utility bills, a home with energy-efficient lighting can be just as well-lit and comfortable as one using traditional incandescent bulbs. The fastest way to capitalize on energy savings is to replace any bulb that operates three or more hours per day with a compact fluorescent bulb. This may include porch lights, living room or kitchen lights. You will notice substantial savings immediately, and according to the DOE, replacing just 25 percent of the incandescent bulbs in your house could cut your lighting bill in half. The trick here is in choosing the correct fluorescent bulb for the job. Flickering and buzzing are common problems in older fluorescent light fixtures, but are easily avoided in new fluorescent bulbs.  

Older bulbs (and some cheap new bulbs) have magnetic ballasts that “hum” at 120 cycles per second, which some people can perceive as a flicker, and which may be accompanied by a buzz as the lamp cycles. (An easy way to identify them is the 1-2 second delay when you switch the light on.) New electronic (or solid state) ballasts operate at 24,000 cycles or more per second, eliminating the flicker.  

The buzz is also gone, since there is no magnetic “pulsing” happening. 

When comparing bulbs, there are three numbers to look for to assure a quality product: watts, temperature, and the Color Rendering Index.  

As of this writing, there are no packaging standards on CFL’s, so these numbers may not appear on each brand of bulb. The watts for compact fluorescent are about one quarter of those of incandescent bulbs. If you use a 60-watt bulb in a fixture, try using a 15-watt compact fluorescent. For a 100-watt equivalent, try using a 25- or 27-watt bulb for equivalent brightness. The second criteria is in the color temperature of the light; that is, what the light from the bulb looks like.  

The unit of measurement that lighting engineers use to rate light temperature is in degrees Kelvin.  

Each manufacturer uses a slightly different blend of materials to create its bulbs; colors can range from blue-white to warm-white to rosey-white.  

Sodium street lights rate are around 2,000 K, and a 40-watt incandescent bulb is roughly 2,200 K while the average 100-watt incandescent bulb is approximately 3,000 K. Halogen bulbs are rated around 3,300 K. 

So, when looking for a good-quality compact fluorescent bulb, look for a temperature rating of around 2,700 K to produce a light that is similar to what you already have in your home. We often hear, “I like a bulb to be the color of sunlight.” Just to clarify things, sunlight ranges from a noontime bright sky of 5-6,000 K to an overcast sky color of 6,500 to 7,500 K (cool blue-ish light), to a northern deep blue sky of 8,500 K. Sunrise and sunset start around 1,500 (deep reds). Daylight changes with the seasons (high or low off the horizon), and is different in every latitude, so no bulb can do that! For a cooler light, look for a rating of 3,500 degrees Kelvin. You might want this color in a kitchen, laundry room or bath, while choosing a warmer light in a reading lamp or living room. Another criteria is the way the light from the bulb makes other colors look, or how close to “true” the colors appear. This is expressed in a scale called the Color Rendering Index, or CRI, on a scale of 0 to 100.  

Think about those orangey sodium street lights. Their color-rating index, or CRI, is very low, in the 30’s, while an incandescent bulb is generally in the 90’s. Our eyes don’t perceive very slight differences in this scale, but we can tell when a bulb is in the lower ranges, because colors look washed out or sometimes grey.  

Look for a CRI number in the 80’s; 82 is a comfortable number and is nearly indistinguishable from an incandescent bulb. Take advantage of the many rebate programs now available on bulbs – some are in-store rebates given at the register, and others require a mail-in coupon. The payback period on a $10 bulb is about 10 months at today’s electricity rates. For the best assurance of a long-lasting, quality bulb, look for the EnergyStar logo from the Department of Energy. 

For more information on energy use, rebates and related products, see the City of Berkeley’s Web site at  


Alice LaPierre is an energy analyst for the city’s Energy Office. Her column appears as a public service the first and third Tuesday of the month.