LED Lighting Questions

[Bill Jobe]

One more thing....do not trust the kelvin numbers on leds. I bought some 3000s and they were much cooler light than 3000k. Even some 2700k leds are cooler than 2700k.

[Dan Friedrichs]

Also, I have been told that leds with an led dimmer actually save you money because when you dim them they flash on and off so fast you cannot detect it, while other bulbs the excess wattage is used up by heating the dimmer and no money is saved.

It would have to be a VERY old dimmer for that to be true. Dimmers today are highly efficient. Many LED bulbs, however, cannot be dimmed.

[John K Jordan]

... Then came across 4000 lumen LED for $35 at BJ's wholesale club. I think they are Lighting America brand...

"Lighting America": Was that (Shinetoo) Lighting America or Lights of America?
Lights of America was sued by the FTC a few years ago for exaggerated claims and outright lies about the life and output of some of their lights. Some of their LED lights lost 80% of their output after just 1000 hrs of use. If they dimmed very slowly only someone using a light meter would notice. (I'm guessing this is a heat dispersion problem. I like the design of fixtures that use the aluminum fixture as a heat sink.) After I read about LEDs losing output over time I started checking new LED lights with a light meter and writing the lux numbers and date on the fixture.

This makes me wonder about the life of LED fixtures in general since many of them don't use replaceable bulbs. The lifetime claims are usually estimated and not measured. You can't believe lumen output claims either - they are often estimated as well since the equipment needed to measure lumens (integrating sphere) is very expensive. And as someone mentioned, color temperatures are also off sometimes.

JKJ

[Bill Jobe]

It would have to be a VERY old dimmer for that to be true. Dimmers today are highly efficient. Many LED bulbs, however, cannot be dimmed.

Are you certain? Mine took a special dimmer and I thought it worked on all leds. But, then, I haven't bought any lately.

[Kurt Swanson]

So I guess my question now is what type and how many lights do I need in a 24' X 36' shop that I'll be using 40 hours a week? T5 or T8's? I'd like to have them on a dimmer switch.
Maybe my electrician will have some answers. He's stopping by this week.

[Charles Taylor]

So I guess my question now is what type and how many lights do I need in a 24' X 36' shop that I'll be using 40 hours a week? T5 or T8's? I'd like to have them on a dimmer switch.
Maybe my electrician will have some answers. He's stopping by this week.

There's a sticky thread at the top of this forum's listing, "Shop Lighting", that can help with some of those answers.

[Curt Harms]

.................................................. ..............

This makes me wonder about the life of LED fixtures in general since many of them don't use replaceable bulbs. The lifetime claims are usually estimated and not measured. You can't believe lumen output claims either - they are often estimated as well since the equipment needed to measure lumens (integrating sphere) is very expensive. And as someone mentioned, color temperatures are also off sometimes.

JKJ

At least one cynic noted that they don't have to last as long as they're claimed to last, they only have to last longer than the company making the claim, and they probably will.

[Dan Friedrichs]

I think the T5/T8 choice is really about ceiling height. The light from a T5 comes from such a narrow tube - if the ceiling is too low, it'll hurt your eyes to look up at the lights. T5's are also more expensive.

Dimming fluorescents isn't advisable. Instead, hook up multiple switches so that you can turn on just a few fixtures, if desired. I've seen 6-bulb T8 fixtures with 2 ballasts - one that turns on only 2 tubes, and one that turns on the remaining 4 tubes.

[Glenn de Souza]

Hi,
As part of a renovation, I installed LED "wraparound" fixtures from a company called Simkar. See photo. You can find them online. I learned about them from the electrician. They look just like surface mount fluorescent fixtures, but they are LED. Supposedly the savings are 35-40% and the rated life is 18 years if used 12 hours/day. I installed six and switched each pair independently so I could have different levels of lighting, and it has worked out well. LED lights come in different color temperatures, I think mine are 4100K which is a nice neutral white. My last garage had fluorescent lights, which worked out just fine also. The LED seems like a brighter, crisper light and for some reason feels easier on my eyes although that could be my imagination.

I don't like changing bulbs, and so I took the plunge going mostly LED in our house a couple of years ago. Time will tell, but so far I'm a believer.

We worked on a commercial TI project recently where they installed lay-in 2x4 LED fixtures from Lithonia that were purchased through Home Depot for around $100 each. They are dimmable and look no different than traditional fluorescent troffers at a glance, but sure enough they're LED. Very slick.

SY920LED4F4441U1-2.jpg

[Bill Jobe]

I have to wonder if the powers that be are not blowing smoke when they claim incandescent bulbs use too much electricity. What I mean is, I live in the midwest and we need to heat our homes for several months each year. Isn't an incandescent 100% efficient since the watts not making light are making heat. Not much, but don't they produce only heat and light?

And someone was behind the florescent thing was just lining his pockets. I had an energy analysis done in my home and the first thing the guy did was replace 6 or 8 standard bulbs with florescent. At several times the cost of incandescent and their poor track record of failure there's not much savings there, if any.
Big business would have been hit pretty hard if everyone suddenly went to led.

[Dan Friedrichs]

Bill, you're right that the energy efficiency of incandescent is 100% if you desire the heating. However, in the summer when you don't want the heating, the power-to-lighting efficiency is REALLY poor - like 1%. Additionally, the heating benefit from incandescents is marginal, since lights are usually in ceilings, etc - not where heat is desired. Finally, heating using electricity is generally the most expensive and inefficient means of heating - burning fossil fuels in a home furnace is much more energy efficient (and often much less costly).

[Curt Harms]

I have to wonder if the powers that be are not blowing smoke when they claim incandescent bulbs use too much electricity. What I mean is, I live in the midwest and we need to heat our homes for several months each year. Isn't an incandescent 100% efficient since the watts not making light are making heat. Not much, but don't they produce only heat and light?
...........................................

In the summer you're paying the power company for electricity to produce light AND HEAT. Then you're paying the power company to power the air conditioner (if you're using one) to remove the heat created by the incandescent light bulbs. If you're some place that doesn't need air conditioning that changes. I read somewhere that incandescent bulbs convert 10%-15% of electricity into light, 85% -90% to heat. Don't hold me to those numbers but I wouldn't be surprised; incandescent lamps produce light by heating a filament to incandescence.

[John K Jordan]

...I read somewhere that incandescent bulbs convert 10%-15% of electricity into light, 85% -90% to heat. Don't hold me to those numbers but I wouldn't be surprised; incandescent lamps produce light by heating a filament to incandescence.

A wikipedia article indicates incandescent bulb efficiency averages 2.2%
https://en.wikipedia.org/wiki/Incandescent_light_bulb

There are recent developments that promise to increase the efficiency of incandescents, converting the heat into light. More efficient than LEDs?
http://www.telegraph.co.uk/science/2...m-more-effici/

JKJ

[Fred Falgiano]

i took a completely different route with LEDs.

I installed 48 bare bulb ceramic fixtures in my 600 sq ft shop with a 10' ceiling. they're on two switches and have Sylvania 5000k 9.5 Watt bulbs. Having so many creates a daylight-like environment with no shadow issues. Since they're standard bulbs, they're relatively cheap (got them on sale for $6 each at Lowe's - usually $8) and as easy to replace as screwing in a light bulb.

The ceramic fixtures were $1.50 each. Junction boxes were $1 each. Add in the wiring, connectors and staples and the whole thing came in under $500 and looks great.

Of course, it took me FOREVER. Junction boxes went up. Wiring went up. Drywall went up (by myself!), finished drywall, painted, installed fixtures/bulbs and that was it!

IMG_7866.jpg

[Bill Jobe]

Daylight temperature lighting is great. I bought my mom a daylight reading lamp because she loved to read and it made a great difference. Also, they are good for helping those with SAD.