Posted by Sherman in Idaho [108.162.245.23] on Sunday, March 27, 2016 at 15:55:20 :
In Reply to: Shop Lights? posted by CSCameron [162.158.255.78] on Sunday, March 27, 2016 at 15:01:31 :
T8 fluorescents with electronic ballasts are the standard these days. They're cheap, available everywhere, highly standardized, and work well. They eliminate the cold-weather, flickering, and noise issues of magnetic ballasts and they're not picky about which tubes you use. I've converted dozens of old fixtures to electronic ballasts and T8 tubes and they work great.
LED "replacement tubes" that plug into a standard ballasted fluorescent fixture are a kludge. You end up with two separate power supplies operating in series, which is never a happy situation. Ballasts were never designed to drive another power supply, and with essentially twice as many parts, it seems to me you'd end up with twice the failure rate.
If you're going for LEDs, go for fixtures that are designed from the start to use LEDs. There are some that look like 4' fluorescent fixtures and some that look like high-bay mercury vapor fixtures. At this point, there's no standardization on replacement LED "bulbs", so you pretty much have to figure on scrapping the fixture when the LEDs fail. Theoretically, they should have a life of 30,000-50,000 hrs, but I've often seen LED lamp panels where one row is not working although the rest are fine. I expect there will be standardization someday, but it's not there yet. In the short run, you should be able to get replacement LEDs from the manufacturer, but I don't expect them to keep making them for long. It will be like the early versions of small fluorescents that came in dozens of different styles, most of which are now very expensive and hard to find.
Another thing with LEDs is that assuming they don't totally die, as they age they gradually get dimmer. Heat is the enemy of LEDs, and a good fixture with plenty of heat dissipation will enhance their life. But rather than replacing them when they burn out, like a normal bulb, you'll have to decide how dim is still acceptable. This is going to be an issue with public street lights, too.
In terms of efficiency, a good fluorescent uses about 1/4 as much electricity as an incandescent, while a good LED fixture uses about 1/5 as much electricity. The LEDs are more efficient, but only a little bit more. Personally, in my buildings, where I have at least 100 troffer fixtures, I'm holding off on switching to LEDs until long-lasting standards emerge that ensure I'll be able to replace bad LED units and bad ballasts(and not the whole fixture) for decades to come. The industry isn't there yet. 4' T8 fluorescents are the current standard and I'll stick with them in the meantime.
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