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Good source for efficient leds?

richmass62 | Posted in Energy Efficiency and Durability on

I am wondering if any vendors provide extra-high-efficiency LED bulbs and fixtures?  I know that theoretically an LED fixture can provide well over 100 lumens per watt. However when shopping for can lights and under cabinet lights I am finding that the products available offer only 60 to 70 lumens per watt.

I already got the can lights so I am now looking mainly for under cabinet lights.

Also there are units out there with transformers… should I steer away from those or are those lights now all able to shut down the transformer when the lights are off?

Here are some specs of lights available, 12 “, that I found:

plt solutions – 5 watt 350 lumens
maxlite  4.3 watt 341 lumens
eshine 12 watt 690 lumens (3 strips)

It looks like I can get better efficiency with an 18 inch T8 bulb. For example I would get 770 lumens for 7 watts with a Satco T8 bulb from bulbs.com. That requires an old school fixture “with ballast bypass” apparently.

Thank you in advance.

 

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Replies

  1. yesimon | | #1

    You can get 210 lm/W with "Dubai" or new UK philips LED lights (https://www.lighting.philips.co.uk/consumer/ultra-efficient). Here are the general ideas around LED efficiency.

    1) Color temperature. The warmer the color the lower the efficiency due to phosphor conversion losses from blue light. LEDs on the blue-end will be more efficient.
    2) Color quality (CRI). The better the CRI the lower the efficiency since losses are incurred trying to replicate the broad spectrum of natural/high quality light.
    3) Power. Mass market LEDs are "over-driven". You can make LED lights more efficient and last a lot longer by running at lower current/power, but using more of them. (This is essentially the Philips ones shown above). Since you need to buy more lights it's going to cost more upfront.

    With this knowledge in hand, you should have what you need to shop wisely. Here's an example: https://www.bestledstrip.com/natural-white-brightest-led-strip-light-24v-4000k-2835-160-5m/

    1. richmass62 | | #2

      Thank you, I was looking for these "Dubai" bulbs. It was hard to find anything like it on Amazon but thanks to your help I now see that I can order 5000K, 4 watt consumption bulbs , that cost $13.47 for two bulbs. The efficiency is 800 lumens (similar to a 60 watt bulb) -- great for only 4 watts of consumption.

      https://www.amazon.com/Philips-Non-Dimmable-EyeComfort-Technology-580506/dp/B0BKH3HMQB/ref=sr_1_2?keywords=philips%2Bultra%2Befficient&qid=1674717309&sr=8-2&th=1

      I will go ahead and try these! I am surprised that the energy efficiency programs run by the utilities do not promote mass adoption of these.

      Obviously the payback may be questionable at $7 per bulb but if they are likely to last a lot longer then I am sure they will be cheaper in the long run than buying a new LED every 4 or 5 years. It is important to get the cost of these down to $4 or less so that they are adopted everywhere.

      1. aaronbeckworth | | #4

        I don’t see how this Philips bulb is a solution for you as an under cabinet light option. What type of fixture would you use for that location?
        -Aaron

        1. richmass62 | | #5

          So far the best lights I see efficiency wise are only 90 lumens per watt. Here is a link.
          https://www.amazon.com/Monios-L-Linkable-Cabinet-Closet-Daylight/dp/B072KJQDHG/ref=sr_1_45

          So the best option is to find a fixture for fluorescent bulbs and remove the ballast. Then, you can use a T5 bulb as listed in the original post, a 7 watt bulb that runs at 120 volts. Satco has 3 options for these 700 lumen bulbs and you can buy them here:
          https://www.bulbs.com/Light_Bulbs/18%22_--_under_30%22-Length_(in)/Miniature_Bipin-Bulb_Base/500_--_749/Tube_slash_Circline/Straight_Tube/results.aspx?lnd=0

          If you need a super bright light you can get a 2 foot LED strips that have a rating over 110 lumens per watt, using 11 watt to generate 1250 lumens. But this is too bright for most kitchens. Here is a link:
          https://www.1000bulbs.com/product/219392/LITH-0765.html#detail-tabs

          A few years ago I obtained a 4 watt LED "T5" type SunSet LED closet/under cabinet light, 11.5 inches and article number F8812-30. T5 is a half inch wide LED bulb. ETL number is 5005726. But they do not appear to make this any more. They do offer a track light replacement that is 100 lumens per watt using an MR16 bulb.

          It appears that the most efficient way to go may be to use an LED bulb designed for low voltage. It requires an LED "driver" and these drivers typically have efficiency of about 90%
          https://www.upowertek.com/led-driver-efficiency/

          For example, a Satco 8 watt bulb that is 2 feet long will put out 1200 lumens. However since the power is first going through the driver you lose some efficiency and you may end up 8.8 watts going in. Still that gives you 136 lumens per watt which is the best product I found overall. It appears that the LED driver may alter the voltage depending on how many LED lights you have daisy changed together, but I am not certain of this. Here are the specs on the Satco bulb I am talking about: https://www.satco.com/products/S11933

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