We decided to give LED lights a try for our overhead track kitchen lights. Thought I would pass on the results.
There is a lot more to buying light bulbs than there used to be!
We had 6 R30 flood lights overhead track lights in the kitchen area. These are the most used lights in our house. When we moved in back in 2000, the lights were incandescents, and we changed them to R30 CFL (Compact Fluorescent Lights) units. The CFLs have worked pretty well, but they do have some delay coming on, and the life has not been that great. The life has proved to be a good deal shorter than the life claim on the box -- this is probably because the lights get turned off and on quite a bit. The lights are about 13 ft off the floor, and in a position that is awkward to get a ladder into, so not having to replace them so often would be a big plus.
The original 6 CFL R30 lights along with a trial run on one of the new LED R20 lights.
The appeal of using LEDs for these lights is that: 1) they would come on instantly, 2) switching them on and off frequently would not shorten their life, and 3) if the life claims are true, we would never have to go up that ladder again. In addition they might save some additional power over the CFL lights.
In looking into LEDs to replace the R30 CFLs, we found:
- They are pretty pricey -- the ones made specifically to replace the R30 size 65 watt incandescents are up in the $40 area. Quite a bit to spend for a light bulb, and we needed 6 of them.
- When the DOE checked on LED actual performance vs manufacturer claims, they found that 78% of the LED lights did not meet the manufactures claims. This note on LED at the 1000Bulbs site is interesting...
So, you have the prospect of paying a whole lot for an LED light that does not live up to the claims made for it -- the worst of both worlds.
- The color quality of the LEDs can be disappointing compared to incandescent lights. Since we spend a lot of time in this area, we wanted the light color quality to be good.
In order to lower the risk somewhat, we decided to just buy one of the LED floods locally and give it a trial run. After looking at the selection at several places, we decided to try an ECO Smart PAR20 LED made by Lighting Sciences and sold by Home Depot. This LED is a 350 lumen, 8 watt unit, and has an estimated life of 50,000 hours. These units were actually intended to replace 40 watt incandescent R20 bulbs, but we decided it was worth a try as they are substantially less expensive than the the R30 units -- they cost $22 each.
We installed the one test LED, and were very pleasantly surprised by the light level -- it appeared to light its area better than the 65 watt equivalent CFL had. This LED is a 3000K color temperature light, and the light is just a touch less warm than would be ideal, but fine. The CRI (Color Rendering Index) for this LED was rated at 85 out of 100 and we were wondering if this would be noticeable, but it seems fine.
Based on the good results with the test LED, we went ahead and bought 4 more of them. We also bought new fixtures to hold the lights. The LEDs would fit in the old fixtures, but the ventilation around the LED heat sink would have been somewhat restricted. We like the looks of the new fixtures better as well -- they are more compact. The old fixtures are going out to my shop and to the local Habitat Restore.
The new LED lights. Note that you can't really go by the photos to evaluate lighting levels or color temperatures.
We have had the 5 new LED floods installed for several weeks now, and are very happy with them. The 5 LED lights provide considerably better lighting than the 6 CFL floods did. The lights come on instantly, and (hopefully) will never have to be changed again.
I'm a bit puzzled as to why five LED floods rated at 350 lumen each can provide better lighting than six CFL lights rated at 750 lumen each. The pattern of the LED's is narrower than the pattern for the CFL's, and that probably accounts for some of the difference, but the narrower pattern works fine in our case. Other factors might be the optimistic ratings mentioned above, or perhaps the output of the CFLs dropping some as they age. What ever the reasons, its just undeniable that these 5 LEDs at 8 watts each light the area better than the 6 CFLs at 15 watts each.
So, this is quite a progression: Started with 6 incandescents at 65 watts each for a total of 390 watts, went to 6 CFLs at 15 watts each for a total of 90 watts, and now on to 5 LEDs at 8 watts each for at total of 40 watts -- nearly a factor of 10 drop in energy use! See the section below for the savings in electricity and carbon.
The new LED lights and fixtures.
The "Lighting Facts" label is important to
read and understand. I would be very
reluctant to buy an LED that does not
have this label.
The PAR20 LED lights.
Made by Lighting Science and purchased
at Home Depot for $22 each.
I'm hardly qualified to give advice on going to LEDs or not, but I will anyway:
The LEDs are expensive and they have a long life -- you will be stuck with any mistakes you make in the selection for a long time, so do your homework carefully before you select a unit. Its different than buying a light bulb used to be. If possible, see if you can try one to see how it works out in your actual situation.
LEDs are not to the point where you can just take the claims on the packaging as the whole truth and nothing but the truth -- to make sure you are getting what you want:
Look for lights that have the "Lighting Facts" label, and learn how to read the label.
Look for lights that have the Energy Star label, as the LED light has to meet a variety of criteria in order to get the ES rating -- not just energy efficiency -- things like a certain level of CRI (Color Rendition Index), not making noise, ...
Before narrowing down to a particular LED or two, look for some reviews of the light by people who have it, and learn what you can about the company that makes the LED and what their reputation is. Quality varies considerably.
When comparing LED lights to incandescents, even though the initial LED price is high, the energy saving is so great that the payback period is short. Its something you can do and be pretty certain it will pay you dividends in a short period of time.
When comparing LED lights to CFLs, the economic payback will take a lot longer, and it may be questionable on a strictly dollars and cents basis whether its worth it or not at this point. In these cases, it probably makes sense to look at the other strong points of LEDs as a guide as to where to start -- good candidates for LED replacements:
- Lights that get cycled off and on a lot (this shortens the life of CFLs)
- Lights that are difficult to change as LEDs have very long lives.
- Lights that need to be dimmed as LEDs dim well and CFL dimmable lights are a bit spotty (but, make sure that the LED you buy is designed for use with dimmers).
- Situations where the CFL delay in coming up to full brightness is bothersome.
- Situations where the mercury content of CFLs could be a problem (although this probably tends to be overblown).
I'll do this first as though we went directly from incandescent floods to LED floods.
I'm assuming the lights are on an average of 4 hours a day. I think that when we are really paying attention, it averages less than that, but there are lapses where the lights stay on for long periods.
Six incandescent R30 floods at 65 watts each is 390 watts.
Yearly power consumption at 4 hours a day is:
(365 days)(4 hours/day)(0.390 KW) = 569 KWH per year
Cost at 10 cents per KWH is $57 per year
Carbon emissions at 1.5 lbs of CO2 per KWH is 850 lbs of CO2 per year!
The CO2 emissions are surprisingly large -- about a eighth of the CO2 emissions of a Prius for a year (15000 miles).
Five LED PAR20 floods at 8 watts each is 40 watts
Yearly power consumption at 4 hours a day is:
(365 days)(4 hours/day)(0.040 KW) = 58 KWH per year
Cost at 10 cents per KWH is $5.80 per year
Carbon emissions at 1.5 lbs of CO2 per KWH is 87 lbs of CO2
Basically, the LEDs in this case end up using about one tenth the power and energy and cut CO2 emissions and cost to operate by a factor of ten.
Cost saving is $51 per year, for a payback period of 2.2 years.
Lifetime saving assuming a 20 year life is $1,020 and 17,000 lbs of CO2.
These numbers are a bit more lopsided in favor of the LEDs because 1) we replaced 6 lights with 5, and 2) we used a nominally lower light output bulb. But, I stand by them in that the room is without a a doubt better lighted than it was before.
Added benefits include the instant on, and not having to go up and down that awkward ladder anymore.
Since we already had replaced the incandescents with CFLs, our actual saving was much less...
The yearly saving in energy between six 15 watt CFLs and five 8 watt LEDs at 4 hours of usage a day is 73 KWH a year, or about $7.30 a year. We were getting about 2.5 years of life out of a set of CFLs at about $18 per set. Using these numbers, it takes about 8 years for the energy savings and the replacement cost savings to reach breakeven with the LEDs. This is probably sooner than would occur in most cases due to our using nominally lower lumen output lights and five lights to replace six lights.
So, the economic benefits of LEDs over CFLs are not nearly as clear as for incandescents, and the payback period is longer, but it still comes well before the end of the LED lifetime.
Gary February 13, 2011