General > General Technical Chat
I thought LED lights were efficient?
<< < (3/16) > >>
SiliconWizard:

--- Quote from: james_s on April 03, 2022, 12:38:20 am ---Personally I would ignore those ratings and look at the lumens per watt, a good baseline is conventional linear fluorescent lamps which are IIRC around 60 lm/W once you factor in ballast losses, or 50 lm/W for the compact lamps intended to replace incandescent. Those old incandescent lamps are only 10-15 lm/W.

--- End quote ---

Yes, the only metric to consider is how much power a given lamp draws for a given luminous power.

Ultimately, in particular for "mundane" home lighting purposes, what matters is whether a given lamp gives you "adequate" lighting by your appreciation, and at what power from mains. Meaning that efficiency is only part of the question for your average use.

If a given LED lamp is more efficient than another kind of lamp, yet draws the same power from mains, but outputs a lot higher luminous power (that you may not need), then it's more efficient, but you gain nothing. Just a thought.
AndyC_772:
If you're reading EEVblog, chances are you don't need to worry about arbitrary letter codes for efficiency - you'll understand the basic concepts of light output and wattage.

I've just replaced all the old 58W fluorescent tubes in my garage with these:

https://www.tlc-direct.co.uk/Products/LTT524HDL.html

Less than half the power (24W vs 58W), and considerably brighter than the old tubes they replaced. I could probably have got away with only fitting one tube per fitting instead of the original two.
wraper:
Also with higher lm/W figure means you get more LED per lamp. For example I purchased Ikea Solhetta bulbs with 470lm luminous flux and only 3.4W power consumption while most of the similar bulbs have the same 470lm luminous flux but on average about 5.5W consumption. Took them apart and IKEA bulb had more than 3 times more LEDs inside. As running LED at lower current increases efficiency.
Siwastaja:
EU energy labels are a complete joke, anyway. Just categorically ignore them, and for each type of gadget, learn enough to understand how actual energy efficiency needs to be calculated. There is no shortcut.

Like wraper said, for illumination, the relevant figure is simply lm/W. Since both lm and W are reported for most types of lighting, it's easy to calculate.

LED itself does not guarantee anything. Many many LED bulbs and fixtures on the market are around 90lm/W. While somewhat better than fluorescent, it's very crappy for LEDs by modern standards, this was maybe state-of-the-art in 2005. But this is what the cheapest stuff is - and sometimes, even expensive stuff is actually the cheapest crap in disguise!

If efficiency matters to you, try to find at least 110-120lm/W LED bulbs, IMHO. This should not break your bank, unlike true state-of-the-art (>150lm/W).
tom66:
Part of the reason so many LED bulbs have poor lm/W is because the LED chips run super hot, which shortens lifespan and reduces efficiency.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod