I recently purchased a 28 year old split level ranch. I am turning the basement and one of the garage spaces into my workshop. The lights down there are 4′ flourescent two bulb units and are probably original with the house. I am wondering how efficient that lighting is. I believe that two of them have bad ballasts because even after a bulb change they still take a while to come on and then occasionally flicker. Electricity is expense in this state and I wouldn’t mind making an investment in good lighting but before I do so I was wondering what you all have in your shops.
Thanks,
Chris
Replies
Fluorescent lighting is, in general, one of the more efficient ways to go, and is the preferred light source for most small and mid-sized shops. The fact that the lamps take a while to light up indicates that they may be "pre-heat". This is an old circuit type and can be readily identified by the presence of a "starter". The starter is a round aluminum cylinder about an inch in diameter and an inch and a half tall. It is usually mounted inside the fixture, and may protrude through the metal pan between the lamps and the fixture. Drawbacks to the pre-heat circuit are the delay in starting, and shortened lamp life (about 25%) when compared to a rapid start cirduit. I'd change over to rapid start when the old ballasts fail.
Jack Lindsey
Older style 4' tubes are rated 40W. New Rapid Start energy effiicent tubes are rated 32W. That's 20% electrical efficiency. Lighting efficiency is further improved through reflectivity and control. Reflectivity is improved by reflectors and painting everthing possible brite white. Primatic lenses give more down light and less glare. And don't forget to clean them once in a while. If I had the money I'd go with top of the line Holophanes. Short of that I'd get fixtures w/ electronic balasts, color corrected tubes and reflectors. What I do have is a hodge podge of freeby tearouts from TI jobs.
John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
32W bulbs are 20% more efficient electrically than 40W bulbs, but are the number of lumens of light given off by both types of bulbs the same? If they are not the efficiency would have to be calculated on Watts/lumen.
I saw in a recent copy of FW an article on shop lighting. In that article the author stated the 32W bulbs are actually less efficient at producing light than the standard 40W bulbs. The "energy efficiency" was stated as a net reduction in energy used to light a fixture.
Chris,
If you want high efficiency flourescent lighting go with Philips 800ma, high out put, low energy tubes, they are about 20% more effecient than your standard 400ma tubes. They cost a little bit more but...
Dano
Actually T8 lamps save a little more than 20% when utilized with efficient reflectors and electronic ballasts. For instance a 4 lamp fixture (I have 4 lamp data readily available) with the old standard 40 w T12 lamps used about 176 watts (due to fixture effect and ballast efficiency more than 4 times the nominal 40 watts) and produced a nominal 12000 lumens. After factoring in typical fixture coefficients etc about 8500 lumens delivered. A similar T8 fixture with electronic ballasts offers a nominal 11400 lumens, but uses only 112 watts! a 37 percent reduction. If the fixture is equipped with reflectors (and often even w/o) the delivered light is greater! Fixtures are more efficient due to the better optical qualities possible with the slimmer tube. By the way the latest are T5 lamps which are even better.
When I redid the basement 10 years ago, I bought cheap surface mount 2 lamp fixtures without ballasts. I installed 4 lamp electronic ballasts (motorola at the time) and wired two fixtures to each ballast. You can buy that configuration from a lighting supplier now I doubt if home depot stocks them. Electronic ballasts at that time were 22 dollars apiece and magnetic watt savers about 12 so I came out cheaper.
Depending on electric rates and hours of operation you can expect paybacks less than 2 years for an 8hr day 5 day a week operation.
By the way 40 w T12s are no longer manufactured although you can get 34 watt "watt miser". Lumens are even lower.
Edited 4/21/2002 11:10:10 PM ET by JANATION
Edited 4/21/2002 11:14:16 PM ET by JANATION
Chris, all questions of energy efficiency aside, I just dislike flourescent bulbs in general. Their rapid, detectable flickering does a number on my eyes when I'm trying to do any kind of close or detailed work, measuring, etc. Even when I was working for "the man," in an office with flourescent lighting, I always brought in a desk lamp with an incandescent light bulb. Of course, the warm light always attracted my co-workers, making my office the "party office"... so maybe that's why I'm self-employed now.
I know there have been a number of articles written about "good, better and best" flourescent lighting, and you've gotten some good responses here... but I'll stick with the old-fashioned bulbs until something more pleasing (to me) comes along in a flourescent (and doesn't cost the moon). Just my penny or two.
David
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