Tuesday, September 03, 2013

exploring efficient workshop lighting alternatives

Musings about upgrading the lighting in the new workshop. Newer lighting technologies have some problems, like cost and radio interference. Last year's newer technologies (like compact florescents) and "regular" florescents and their descendants have disposal issues because of the contained mercury..

Hello from my new home in Lion's Head! I am moving in and setting up. It is great to be here.

This is the wood shop in back of the garage. The solid wood walls and the white ceiling make for a pleasant space.

In this room there are 4 ceiling mounted rapid start dual 40 watt fixtures, probably about 10-15 years old. One of the fixtures would not light. I could not find 40 watt bulbs locally. The newer 32 watt bulbs fit in the fixture but they won't light up.

There are four more of these dual 40 watt fixtures in the other rooms, eight in total. Each uses 80 watts of energy so (8x80=) 640 watts. You might have fixtures like these and haven't given them much thought since they are pretty reliable. As of July 1 2012, 40 watt T12 bulbs are no longer manufactured in the US.

Should I retrofit or replace all of them and with what? I wondered how these older florescents would start in the winter before the wood stove heats the building? Florescents, although improved with the T8 types, use more energy by comparison to LEDs. Florescents, including the CFL type contain mercury so they are a disposal issue. LEDs are instantly at full power in any temperature.

I have found that both the LED and the T8, while giving great light from much less energy, cause radio interference in the FM band. The FM signal is weak here so it is a tough test. I like to listen to the radio while I work. I have not overcome this problem yet. The old fixtures do not cause this interference.

For the florescent, I had to change the ballast and it turned out to be easier to take down the fixture. This gave me a chance to clean it thoroughly which took off years of grime - the fixture is white now and will give better lighting. It was also MUCH easier to work on the bench than on the ceiling.

Any damaged bulb support posts should be replaced. The T8 rapid start, whether the bulbs are large or small diameter, use the same support posts as the T12.

I could not buy new replacement 40 watt tubes for the one that would not start. Only 32 watt bulbs are available now. These new tubes fit (the pins are the same) but will not start in the older fixture unless the ballast is replaced, or the entire fixture. The ballast is the power supply, the block inside the fixture with all the wires. Hard to see in the picture but this one is oozing a black tar like goop. This one is bad.

The fixtures and tubes are dirty so they are not putting out as nearly as much light as they could be.

Cost to retrofit one florescent with newer T8 technology:

  • New 32 watt tubes 2x5 $10
  • New solid state ballast $15
  • remove clean and replace $0 (or have an electrician do this for you)
  • Total $25

With T8 bulbs, each fixture would draw 64 watts or (8x64=) 512 watts if all were retrofitted.

The 17 watt Philips LED bulb however was $44. It is one I have used previously. Would it really compare with only 1/4 the power?

Because the LED is a common screw base (called a T26 base) I had to take down one of the florescent fixtures and temporarily attach a pigtail socket in it's place. I screwed in the LED to the test socket. This was not a permanent installation.

The light quality from the LED was warm white and pleasing. It is very bright. I didn't have a lightmeter so the comparison was totally subjective. The LED certainly was, to my eye and to several visitors, suitable as a worklight. I would probably double them up like the florescents so that there were two LEDs used as a replacement for each of the florescent fixtures. The total energy use per pair would be (17x2=) 34 watts, about the same as one T8 bulb, but at three times the cost! How to mount these will take some study. Perhaps I could reuse the florescent fixtures to mount LEDS (more about that later).

For now, I have removed the LED and retrofitted two of the florescent fixtures with T8. The T8 are on a different switch from the older T12 so if I want to listen to the radio for now, I need to leave off the newer lights. Not a permanent solution.

This is a sample what I hear when I turn on either the T8 or the LED.

Improving the shop lighting will be a work in progress.

Thanks for your interest. If you have ideas about this, I'd appreciate hearing from you.

More about T12 vs T8 Reference

shop lighting reading list
a parabolic workshop light
led household bulbs
exploring efficient workshop lighting alternatives (this article)
work light led retrofit
testing fluorescent light fixtures - the test jig
testing fluorescent light fixtures - the test method (video)
testing fluorescent fixtures - 40 watt
efficient workshop lighting 2
updated bench lighting


frazelle09 said...

i suppose you might try just plain aluminum foil around whatever is causing the interference...

We hope you will continue to post. We are still very interested in your progress on the solar hot water heater system and the new changes you have made to it. We have already incorporated the ones we could find - the long angle pieces instead of the furring.

Have a wonderful afternoon and we hope you are settling in well up there in beautiful Canada! :)

Rod Layman said...

Great article George!

I have had radio frequency interference issues as well, and have had some luck extending the FM antenna for the radio so that it is further from the source of the interference: this may not work if you use a simple wire from the radio's antenna post (if it has one) but may work if you can use a piece of shielded TV cable, grounded at the radio end, to shield the antenna until it's some distance from the interference. How long should the extended antenna be? Added to the end of any reasonable length of shielded coax, use the length of the existing antenna that came with your radio and make your new, longer one, a straight multiple of that length -- for example, if the FM antenna is 36 "" long then make the new antenna, beginning where your coax ends, 36, 72, or 118" long.