I want to get compact fluorescent bulbs because they save money and may help my children read and study better. Which are most economical and best for the kids?—Pat F.
You will probably want to buy different compact fluorescent lights (CFLs) for various locations in your house. There are many shapes to fit any lamp or fixture.
I have used standard CFLs for years to lower my utility bills, but I recently tested some of the new high-visual-acuity CFLs in my home and office. I normally have to wear reading glasses to read the telephone book, but I can often read it under these new lights without my glasses.
It is important to understand that the wattage rating of a light bulb measures how much electricity it uses, not the amount of light it produces. A standard incandescent light bulb consumes about 100 watts of electricity to produce the same brightness as a 23-watt CFL. When you count up the number of light bulbs lit in your house at night, using CFLs gives a huge savings.
CFLs also last 10 to 12 times longer than incandescent bulbs (10,000 hours of use compared to less than 1,000 hours). With many standard CFLs priced as low as $7, the lower bulb-replacement cost is an additional savings.
Fluorescent bulbs work by ionizing a small amount of mercury, which produces ultraviolet light (UV) rays inside the bulb. When these UV rays hit a phosphor coating on the inside of the bulb or tube, it produces visible light.
The least expensive CFLs use a single-component halo phosphor. It is inexpensive to make, energy efficient, and is acceptable light for hallways, closets, and general lighting. These will have a CRI (color rendition index) of about 60 to 70. The CRI rating indicates how true colors look under the light. The sun provides the truest color at a CRI of 100.
The next level of CFL uses a more expensive tri-phosphor coating inside the bulbs. This produces better quality light with a CRI of about 85. More expensive CFLs with CRIs in the 95 range closely simulate natural daylight. You can find these only at professional electrical supply outlets and custom lighting shops.
The special CFLs that make it easier to read without glare and work with fine detail are often called “full-spectrum” because they simulate the full-spectrum light from the sun. Check for this on the packaging. Their CRI is in the 93 to 96 range, so they also produce natural-looking light.
They are actually much different from the other CRI-95 CFLs, though. These full-spectrum bulbs produce a higher ratio of scotopic light to photopic light, similar to the sun. Remember, humans have worked and read under artificial lighting for only about 100 years, so our eyes still are more effective (visual acuity) under natural light. Scotopic light is sensed more by the eye’s rods (black and white) and photopic light affects the eye’s cones.
When selecting your CFLs, look for ones with integral electronic ballasts built into the base. The ballast controls the amount of electric current that flows through the bulb. Electronic ballasts reduce annoying flicker and buzzing.
If you have the lamp or light fixture on a dimmer switch, make sure to purchase dimmable CFLs. Standard CFLs will not operate if you attempt to dim them. There are also new three-way CFLs that will fit in any lamp with a three-way socket. For lamps with a large shade, consider using a circular CFL. These have a separate electronic ballast base that lasts three times longer than the replaceable bulbs.
Write for Utility Bills Update No. 936 for a room-by-room lighting guide. Include $3.00, a business-size SASE, and Update number. Mail requests and questions to James Dulley, Kentucky Living, 6906 Royalgreen Drive, Cincinnati, OH 45244 . Go to www.dulley.com to instantly download.