Replacing fluorescent bulbs with LED bulbs?

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Charlie Schultz
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Replacing fluorescent bulbs with LED bulbs?

Post by Charlie Schultz »

Hi all,
I've got a few fluorescent bulbs dying in my fixtures and I'm considering replacing them (bulbs and/or fixtures) with LED versions. Mine are all 4' long and a mixture of T8 and T10 sizes. Anybody have any recommendations? I think I'd want the CRI (color rendering index) to be at least 90?
David King
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by David King »

I saw some newish 4' LED shoplights at Home despot for around $40. You may still need to wait around for a CRI of 90.
These are CRI of 80: http://www.homedepot.com/p/Commercial-E ... /205331022

Here are some T8 LED bulbs that hit CRI of 90 for $19 ea http://www.e-conolight.com/lt821935.htm ... aQod-F8GIA
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Jim McConkey
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Jim McConkey »

Around here the LED T8s are going for about $10 each, same on Home Depot's web site. The CRI is only about 80, as David says. Lowes has some different bulbs, but no CRI rating is given. What is CRI anyway, and does it really make that much difference?
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Charlie Schultz
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Charlie Schultz »

Thanks all.

From wiki: "A color rendering index (CRI) is a quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source". Does it matter? Not sure how much the actual number matters, probably "warm white" is good enough (I've gotten some pretty ugly fluorescent bulbs in the past).

Beyond that, given the (supposed) long lifetime of the bulbs, is it worth switching to a non-ballast fixture (and corresponding bulbs)?
Bill Raymond
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Bill Raymond »

I think it is worth switching. I believe that LEDs will become the standard lighting for household and shop in the future. I've switched all my household incandescent bulbs for LEDs and they work very well. The early LEDs didn't dim well at all, but they've gotten better and cheaper. When I can, I'll switch out the dedicated fluorescent bathroom and kitchen can lights to LEDs, too. I'm planning to light my shop with LEDs, but at this time I'm just using our natural sunlight until I get around to installing the lights. I've really not paid too much attention to CRI: It seems that the "warm white" bulbs are good enough for me.
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by David King »

Charlie, that last one is an excellent question. I worry about the life of the ballast for one thing as several of mine have gone bad over the years. Presumably the load from an LED bulb would be quite a bit less than a normal or high intensity fluorescent bulb and there is no need for a starter. Then again LEDs are ideally powered via DC at around 3-12V so it makes little sense to power them through two sets of inverters and a quad rectifier if one or two of those could be eliminated. The best ballasts are probably only 90-95% efficient.

The CRI question is valid but it all depends on if you can get some natural light into your shop for at least part of the day.
If you look at the sun's color spectrum as filtered through the atmosphere it is full of random spikes and troughs which makes it difficult to replicate. You want to have some light from all all colors getting through, not necessarily the exact distribution of sunlight's energy. What you don't want is a light that skips over portions of the spectrum completely. I tried to do this with fluorescents by mixing up different tubes and it was a definite improvement over having just one color temperature say 2.7K or 5K.
In some near future we will have the 4' LED bulbs that will have controllable RGB function like your computer screen. For now that's only available on the screw type bulbs and at a steep price.

I've been going the incremental route, replacing all my swing arm bulbs from CF to LED since those are under $2 each and they start instantly at full output. I was gradually replacing my 8' T12 as the bulbs died with new T8 ballasts and bulbs. At this point I should probably scrap the remaining ones and start over with something better (which is perennially just over the horizon). Europe got to migrate to T5 bulbs for a while which it looks like we will be skipping over completely.
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Barry Daniels
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Barry Daniels »

LEDs and dimmer switches are not very compatible. We went through a lot of hoops to eliminate buzzing. But even the high price dimmer recommended by the lighting shop buzzed with the LEDs. I don't think the technology on this is quite resolved yet.

I am replacing all the small bulbs in our RV with LEDs mainly because they use a lot less of my 12 volt battery's capacity.
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Jim McConkey
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Jim McConkey »

My experience is different with the dimming. The early LEDs may have had a problem, but the newer generation of bulbs do not. Over the past year I have replaced four rooms full of 65W incandescent ceiling bulbs, which buzzed like crazy on a dimmer, with LED equivalents. All the lights in one room together now use less power than just one of the old bulbs used to, and they dim from full to nearly off with no audible sound at all. And very little heat. Dimmer technology has evolved with the bulbs, and each dimmer has ratings for the types of bulbs it is good for. For one of my rooms, I replaced a straight switch with a new dimmer switch in one of my rooms, but for the other 3 rooms I still have 1990s vintage dimmers, and they do not cause any bulb noise.
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Gordon Bellerose
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Gordon Bellerose »

I have changed my fluorescent bulbs and ballasts out for the newer style.
It made a huge difference in the quality of light, longevity, and stability. (no quivering bulbs)
I need your help. I can't possibly make all the mistakes myself!
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by David King »

The main issue with dimming LEDs is that you don't get the color change that you would with an incandescent bulb. There are LED bulbs that do color compensate as you dim. My other problem besides the noises coming from the dimmer switch is that different brands of LED bulbs dim differently so one or some will end up much brighter than the others. Again this isn't a wood shop issue. One thing I noticed on the dimmered and 3-way switched LEDs is that they glow ever so slightly all the time even when switched off.
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Bill Raymond »

I have some lights on a 3-way switch circuit with dimmer and not noticed any "off glow". I have a couple LEDs in our stove vent hood that have a 3-position switch (off, low, full light) that do glow on the low setting, so we have to remember to turn then fully off or fully on, not using the low setting. The lower power required for LED lighting is a real improvement since we're off-the-grid on solar with batteries and generator backup for the occasional spell of gloomy winter days here.
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by David King »

Bill, is your system low voltage DC or are you using AC inverters to run everything at 115VAC?
I think my afterglow comes either from leakage or from induced current into the long switched leg from adjacent wiring.
Back to the topic at hand I've read recently about how existing CAT5 office wiring is being used to deliver low voltage DC for new LED lighting. I can't quite remember what the benefit is but there's undoubtedly miles of underutilized copper going everywhere in office buildings. The next breakthrough will be bioluminescence. Everything will glow a nice soft blue-green all the time, guitars included. :?
Last edited by David King on Sat Feb 20, 2016 3:04 pm, edited 1 time in total.
Bill Raymond
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Bill Raymond »

David, we have 32 Kyocera 215 W panels and 32 L-16 batteries that feed 48V into a 6.6 kW pure sine wave inverter with a Kohler 8.5 kW propane generator for backup. We have 220VAC for the well pump, and a couple 220V outlets in the shop. The only alternative for us was to have PG&E extend their expensive lines to our location. We've had this setup for about 5 yrs now and are very happy with it. I'm finally getting around to installing an automatic generator start so I don't have to run out in the rain to start/stop the generator when necessary.
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by David King »

Living the dream! Do you find it limiting in terms of when you work in the shop? I think if I had to get my work done while the sun was shining I'd probably get a lot more done in less time and be happier all around
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Bill Raymond »

Not really limiting, David. The batteries provide enough storage (401 Ah each for a total of 1604 Ah in the series/parallel configuration to provide 48V) to provide sufficient round-the-clock power. On most sunny days (all summer long here in northern CA, and pretty much sun during the winter, too) the batteries are fully charged by midday. I don't, however, work much at night since the shop is a bit of a walk from the house and I don't like to run into wild pigs in the dark. There are also other predators about--the rare mountain lion or black bear, coyotes (though they aren't that much of a threat to adult humans).
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Dave Weir
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Dave Weir »

The technology hasn't really settled for the LED replacement tubes. The cheap ones at home depot don't work with all ballasts. There are others that you disconnect the ballast altogether, and there are different ways these get wired. Some from one end, some from both ends.
There is no doubt L.E.D.s will replace almost all other lighting very soon. G.E. has discontinued High Pressure Sodium and Induction street lights altogether. I've changed all the screw in incandescent to LED. But I don't think the tube replacements are quite there yet. I put some in a bathroom and had to put little aluminum spacers on the ends to make good contact. The 4' tubes for 9 dollars at HD would not light up at all. If you get ones that work with your ballast, the ballast will fail before the led tube, and then you have a new dilemma.
I'm trying to hold off a little longer, but if I was to change now, I think I would get a whole new fixture, designed for LED.
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Re: Replacing fluorescent bulbs with LED bulbs?

Post by Michael Lewis »

Charlie, I put some LED strips up under our kitchen cabinets, and it really is great to be able to see what I am chopping on the cutting board, or where did that dollop of peanut butter go? Got them from a place called Superbright LEDs. They come in self stick strips or on a reel, you get to decide. They have various concentrations of light, and colors if you are looking for such. I recommend them.
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