Cheap LED is flooding the market and it’s good to know why quality is worth paying for. Here is a quick guide that I’ve given to my people on what makes quality LED different than most of the cheap junk now on sale.
In lay terms, lumens is brightness. This should be the first measure of quality in LED. It’s’ possible to buy a cheap LED recessed trim, for example, at a box store or on Amazon if you’re willing to settle for 600-800 lumens and live in the dark. In most applications, I recommend at least 1,000+ lumens for a ceiling that is 8′ or higher because all LED’s dim over time (more on that in the “L rating” section) and what might look great for a year or two often ends up as a dimly lit nightmare long before the life of the LED is up.
- DELIVERED LUMENS
Possibly the most important reason to buy LED technology through a lighting showroom rather than anywhere else. Light loses intensity as it travels and a good lighting expert will help calculate the lumens needed for each room. Buying without the assistance of an expert usually means living in “the dim” or having light so intense that it feels like you’re in the beam of an alien abduction ship (more on that under “beam spread” below).
Delivered lumens refers to the amount of light that gets down to where the light will be used… usually 3-4 feet above the ground. Delivered lumens MUST be calculated per specific room by factoring square footage and ceiling height. It cannot accurately be listed on the box of an LED product because it’s specific to the room of installation (though some manufacturers mistakenly put “delivered lumens” on their box where they really mean “lumens”).
I contend that you can’t buy quality LED without the help of an expert who knows how to calculate the necessary delivered lumens for each room.
(note: if you need a guide on how to properly calculate delivered lumens, email me and I’ll send you one that we’ve developed and use in our stores)
- BEAM SPREAD
It’s very possible to have an LED that delivers plenty of lumens… but only in a narrow “spotlight” area. There are certainly some applications for a spotlight, but for general lighting it’s better to have a wider beam spread (usually as close to 180 degrees as possible in trims and disks, and as close to 360 degrees as possible for bulbs). Usually cheap LED will make itself look good by having a decent lumen rating but then when you look at the beam spread you realize that it’s all delivered into a small area. High lumens with insufficient beam spread is a good way to feel like you’re living in the fridge… harsh, bright spots of light surrounded by dark areas, hidden corners, and maybe even some nasty leftovers.
- CRI RATING
CRI stands for Color Rendering Index, which refers to the amount of color that your eyes will see under a particular light source. Unfiltered sunlight produces 100 CRI. Artificial light often falls short of that.
Think about the last time you walked inside from a nice bright day and everything looked dim and murky. Part of that is the amount of light outside vs. inside, but most don’t realize that another big part is that you’ve just gone from a high CRI environment into a lower CRI. The brain never stops trying to figure out where all the color went, so it will often keep “processing” to try to see the full spectrum of color, and many health experts feel that low CRI contributes to headaches, fatigue, and perhaps even more serious things like depression.
Cheap LED will have a CRI in the 80-90 range where the best LED will always be at least 90 and ideally shoot for 95+ CRI.
(note: we purchased the same photo spectrometer as those used by NASA to test lighting quality. We test samples of every LED that we sell to make sure that the lumens and CRI are accurate as listed on the box… I’m surprised by how many aren’t!)
- L-RATING & EXPECTED LIFE
This is one that even most showrooms haven’t heard of. L-Rating refers to the “Lifetime Rating” for the diodes in LED’s. Diodes have a half-life, which means that they’ll eventually be half as bright as they are when new. What most don’t know is that the rated hours for an LED is how long the diodes are expected to last until they hit half their original brightness.
In simple terms, if you have an LED with a 15,000 hour expected life and an L-Rating of L50 (note: this is VERY common on the LED’s I see in box stores and online) that means that at 15,000 hours the lumens will be half as bright. Usually the LED is so dim as to be incomfortable years before it ever gets to 15,000 hours. An L-Rating of L70 means that the lumens will be 70% as bright at the rated life. Most cheap, mass-sold LED will have a lower expected life and an L50 rating. Again, that will look great for about two years, and then begin to dim to the point of being unbearable.
The very best LED will have an L70 rating at a 50,000+ rated life.
We place a lifetime warranty on any LED that we sell, and we require vendors to get behind us on that. It’s simply too expensive for people to invest in LED that will poop out in a year or two or start to dim to the point of discomfort, so we search for LED vendors that will stand behind us with high L-Ratings and 50,000+ rated hours (which, in combination, is far longer than almost any normal user will ever need) and then agree to warranty anything that fails at any time. Most vendors will place a time limit on their warranty, but so long as it’s more than 5 years and they have a good L-Rating and lifetime expectancy, we’re willing to take the risk of giving our added warranty beyond the 5 years.
- HARMFUL BLUE LIGHT
This is a little more advanced but is gaining momentum – especially with people raising awareness about the harms of computer screen and phone screen light. Poor quality LED will have an unbalanced-spectrum light. That usually means a big spike in blue light. Diodes naturally glow blue, so you have to layer them with quality phosphors to make the light non-blue. Usually cheap LED manufacturers will use lenses and tricks with cheaper diodes/phosphors (the diode and phosphor selection process is known as “binning”) to try to hide the harmful blue light. Your eyes might be deceived but your brain can’t be fooled.
Most packaging won’t say anything about harmful blue light, so if you want to sell the healthiest LED, you’ll have to ask your manufacturer for a light spectrum report or a blue light measure (look for something below 15%).
Below is a link to view. The best quality LED will have “full spectrum” light that is as close to the left-most image (natural sunlight) where cheap LED will usually have a big spike in blue light: https://iristech.co/wp-content/uploads/2018/06/different-light-sources.jpg
Lighting spectrum is also measured with a good photo spectrometer.
(note: If you don’t want to spend on a photo spectrometer – the one we purchased cost about $3000 – but could benefit from a list of quality LED’s that meet pretty strict quality requirements, let me know what types of LED’s you’re selling and I’ll send recommendations)