6500K (Daylight) CFLs......

[ddrueding]

Thanks you, jtr1962....

After reading the Nichia Develops 60 Lumen Per Watt White LED thread, and jtr's information on high-temp CFL bulbs, I've been thinking of giving them a try. I finally was ablt to get 5 6500K, 1100 Lumen CFL bulbs locally for ~$8. I love them. Thanks again for the great info!

These bulbs do not state their CRI rating, is it different for different 6500K CFL bulbs?

 

[jtr1962]

You're quite welcome. I'm glad you enjoyed that thread. It's come to be one of my favorites around here. Regarding the CRI rating, most CFLs tend to be at least in the high 70s or low 80s, so you will get pretty decent color rendering. Do reds look red or do they look a little washed out? And yes, different makes of 6500K CFLs will have different CRIs. It depends upon the phosphors used. Rare earth phosphors are almost always used in CFLs (as opposed to halophosphors used in the early greenish cool-white fluorescent tubes with poor color rendering), and for really good color rendering you will see some with triphosphors (those tend to be expensive, and are generally sold as full spectrum, CRI>90, and color temp in the 5000K to 5500K range). In fact, I just replaced the fixture in my bedroom with a 4-tube one from Home Depot. I'm using the same full-spectrum T-8 tubes that I mentioned in that thread. Only problem now is that I get too much glare on my screen when the light is on. :mrgrn: Other than that, it looks like I have a skylight in my bedroom at night.

I'm using a 19W, 6500K CFL (made by Commercial Electric and sold in Home Depot for $7.95) in my desk lamp and I love it as well. Much nicer than the more commonly available 2700K or 3000K CFLs which resemble incandescents. Unfortunately, getting any high color temp CFLs in most home centers is practically a lesson in futility. I was surprised Home Depot actually had daylight CFLs. Judging by the specs you gave, I think you're using the same CFL. No mention of CRI on the package, but reds look pretty decent to me (not quite as good as my full-spectrum tubes but not bad either) and anything metallic looks awesome under 6500K.

Were you dissatisfied with the more commonly available low color temp CFLs as well? I've found 6500K lighting creates a soothing atmosphere while 5000K seems to be better for a work environment. I'm still not sure if I'll keep the 5000K tubes in my bedroom or go back to 6500K. I always have my desk lamp if I don't for those times I want lower light levels and 6500K as opposed to 5000K. However, 5000K is great for reading, color matching, close work, etc. I hope eventually we'll have fixtures with LEDs where you can change the color temp to suit your mood, or even go with colored lighting for occasions. We could do it now with computer control of enough LEDs in the three primary colors (red, yellow, blue), but the efficiency wouldn't be anywhere near fluoro tubes and you would need thousands of LEDs for decent light levels (at $0.25 each and up that gets pricey).

 

[ddrueding]

I went to Home Depot and those are indeed the same bulbs as I got (just bought them out). I hadn't even tried the other CFLs. Heat, efficency, and lifetime aren't really concerns for me; just the high color temp and fuller spectrum.

So 5000k is better for reading? If so I'll have to get a hold of one for my bedside lamp....

 

[jtr1962]

So 5000k is better for reading? If so I'll have to get a hold of one for my bedside lamp....

Probably if you're reading a magazine or anything else with a lot of colors. You'll be able to see subtle differences in color better. If it's mostly text, the daylights are fine, and they still have pretty decent color rendering for photos. Both are much better than incandescent. Greens and especially blues look washed out under incandescent. For reading I tend to think intensity is most important and I wouldn't sweat it too much whether I'm using 5000K or 6500K.

Heat, efficency, and lifetime aren't really concerns for me; just the high color temp and fuller spectrum.

I've always preferred fluorescent lighting because it is closer to daylight. Until recently, the efficiency concerns weren't too important to me, either, except in the sense that to light a room to levels I feel comfortable with would require a ridiculous wattage of incandescents, and these would generate far too much heat. Now of course I'm glad my preferred method of lighting also happens to be one of the most efficient and longest lasting. Sure, sodium vapor and metal halide have somewhat better efficiencies but aren't practical for room lighting (too expensive and in the case of sodium vapor very poor color rendering).

 

[e_dawg]

Two questions:

1. Daylight flourescent tubes (the 48" tubes, that is) don't look like daylight to me. They look very cold and bluish. I am not seeing the "full spectrum" they are supposed to be putting out. Is it only me? Are those daylight compact flourescents actually fuller spectrum than their long-tubed cousins?

2. Anybody know where to get these higher temperature CFL's in the Toronto area? I'm lucky if I can even find CFL's in high enough wattages (>23 W) to be able to use them in place of 100 W incandescents.

 

[LunarMist]

I do not recommend 6500K lighting for general use. Some sensitive people suffer more depression and are less productive in bluer light. 5000K or even 5500K lights are more pleasant and tend to make people feel better.

 

[e_dawg]

Anybody tried Sylvania Daylight bulbs?

http://www.sylvania.com/home/daylight/

They seem like a good alternative to regular incandescents

 

[sechs]

I order most of my CFLs online at http://www.topbulb.com. I don't know if they go north of the border, but they do have a serious selection.

At home, most of the bulbs that we have are 2700K to 3500K. I've been in a colour lab where they used "daylight" lamps, and it felt wierd. Actually, creepy might be a better word. Even on a bright, sunny day, the kind of natural light that you get inside isn't the same as what you get outside; and it didn't feel right to get the kind of colour that I was seeing.

I've been looking into progressively cooler lighting, but because I use CFLs for their efficiency and not their colour rendition, I usually end up getting the cheaper 2700K lamps.

 

[e_dawg]

Speaking of higher temperature lighting, I just remembered that nobody discussed automotive lighting yet. I use Sylvania Silverstars in my Jetta, as I Xenon HID's were not available as an option on them, and I wanted something better than the standard halogen lights. The Silverstars are 4000 K bulbs, compared to the standard 3000 K, and they're a little brighter, too. Excellent upgrade for your car if you don't have HID. I'd recommend it to anyone.

http://www.sylvania.com/auto/silverstar.htm

And speaking of temperatures, the 4000 K of the incandescent Silverstars is actually very close to what I think of as full spectrum daylight. If they had a slightly cooler version of the Silverstars -- say 4300-4500 K for home use, I think it would be the perfect spectral balance for my tastes. So far, the mass market flourescents strike me as horrible.

 

[sechs]

I strongly dislike HID car amps for two reasons:

1. They are high intensity (i.e. too bright), blinding other drivers on the road.

2. They tend to be too white, making it difficult for other drivers to maintain their night vision.

 

[jtr1962]

1. Daylight flourescent tubes (the 48" tubes, that is) don't look like daylight to me. They look very cold and bluish. I am not seeing the "full spectrum" they are supposed to be putting out. Is it only me? Are those daylight compact flourescents actually fuller spectrum than their long-tubed cousins?

I think the daylight tubes are meant to simulate the combination of sunlight and skylight which averages to a color temperature of 6500K. You're right about them not looking exactly like daylight. Daylight is a combination of a ~5500K point source(the sun) and the bluer sky(not sure of the color temp, but probably over 10000K). I tend to think of daylight tubes more as another means of creating a mood, much the way incandescents or candles can be used for the same thing, rather than an exact imitation of day time lighting conditions.

2. Anybody know where to get these higher temperature CFL's in the Toronto area? I'm lucky if I can even find CFL's in high enough wattages (>23 W) to be able to use them in place of 100 W incandescents.

Online is probably the best way. It seems that except for specialty lighting stores where you pay ridiculous prices you just can't get higher color temperature CFLs. For whatever reason the general public is used to the incandescent type lighting of the more commonly available CFLs. I tend to equate this with a bad habit more than a rational preference as studies show people are more productive in light that simulates sunlight.

If they had a slightly cooler version of the Silverstars -- say 4300-4500 K for home use, I think it would be the perfect spectral balance for my tastes. So far, the mass market flourescents strike me as horrible.

Very true. 5000 to 5500K is close to sunlight at the equator. I think at more northern latitudes the color temp is somewhat lower due to the angle of the incoming sunlight (atmosphere tends to filter blues which is why sunsets look orange). Regarding mass market fluorescents, they are getting better, especially the T-8 tubes. Mass produced cool white T-8 tubes have CRI in the high 70s or low 80s. I'll agree though that many types of tubes, especially warm white, as well as the warm white CFLs, are horrible, but then so are incandescents. It's a pity more people haven't discovered the benefits of full-spectrum lighting so that mass production would bring the prices down.

BTW, the Silverstars get their higher color temperature from filtering out some of the the reds and yellows, not by burning the filament at a higher temperature (tungsten lamps are limited to ~3400K). As such, they are even less efficient than regular incandescent lamps. That's fine for a car, but to light a room brightly with those would use a very large amount of power.

 

[Handruin]

I strongly dislike HID car amps for two reasons:

1. They are high intensity (i.e. too bright), blinding other drivers on the road.

2. They tend to be too white, making it difficult for other drivers to maintain their night vision.

I don't mind them, but yes I am biased since I have Xenon lights. They do appear brighter than regular halogen lights, but they don't bother me from on-coming traffic. Since I wear glasses, I have a harder time seeing at night, so these help me very much.

The only time I find HID's annoying is in massive-large snow flakes. The reflection is more apparent. Other than that I feel it improves my vision and I don't encounter any issues with maintaining night vision. I do notice a significant different when I drive in a car without them.

 

[jtr1962]

Anybody tried Sylvania Daylight bulbs?

http://www.sylvania.com/home/daylight/

They seem like a good alternative to regular incandescents

Those are similar to GE's Reveal bulbs. Both have a blue neodymium coating to bring the color temperature up a bit (this absorbs some light and brings efficiency down a bit). We have some Reveal bulbs in the dining and living room chandeliers. It is a big improvement over regular incandescent lighting. However, it still is an incandescent with all the inherent disadvantages (low efficiency, short life, too much heat generation). And the light still looks yellowish compared to fluorescent even though it is whiter than regular incandescents. I would rather ditch the chandeliers in favor of a nice fluorescent fixture but my mom won't hear of it (she likes the way the chandeliers look even though she's not crazy about incandescent lighting either). Comparing the dining room light levels (300 watts incandescent) with those in my bedroom (full-spectrum fluorescent, power draw 102 watts according to ballast specs) with a light meter shows my bedroom to be four times brighter! Or put another way, to light the dining room (similar overall size) to the same level with those small base cadelabra bulbs would require ~1200 watts.

I'm thinking LEDs will be the answer (eventually) to those who want to keep their incandescent fixtures but want higher color temp and efficiency.

Are those daylight compact flourescents actually fuller spectrum than their long-tubed cousins?

I really didn't answer this part of your question but it depends on the phosphors used. Some daylight tubes actually have better CRI than daylight CFLs. The ones I was using in my bedroom until yesterday had a CRI of 85 (Philips Alto brand Daylight Deluxe available in Home Depot). I'm guessing the daylight tubes sechs mentioned that makes things look an eerie blue are deficient in reds and have a so-so CRI.

 

[jtr1962]

I strongly dislike HID car amps for two reasons:

1. They are high intensity (i.e. too bright), blinding other drivers on the road.

2. They tend to be too white, making it difficult for other drivers to maintain their night vision.

True on point 1 if they aren't aimed properly. Regarding point 2, I've found that with white LEDs on my bike headlight (similar in color temp to HIDs) it actually works better with my night vision. Peak night vision sensitivity is in the blue-green area, so higher color temp lights will work better at night all other things being equal. I found this by directly comparing a 2.4 watt halogen bulb with an LED array driven at ~1.7 watts. Lumen output for both was fairly similar but things looked much brighter in the cooler light of the LEDs.

 

[sechs]

HID lamps are great for drivers, unless you don't have them.

Part of the problem is that street lighting is usually high-pressure sodium, which is a pleasant orange colour. Your eyes become accustomed to that colour, and then two bright white monsters come along, and everything is messed up.

If the lamps were aimed differently, that would make a difference, but would make them less useful to those who have them.

 

[jtr1962]

I never thought of it that way but you may be right. Those sodium vapor streetlights take some getting adjusted to, so I can see how HID headlights can throw everything off again. I noticed the other day going across the Whitestone Bridge that the lights were changed to metal halide (they used to be sodium vapor). Metal halide is essentially a white, high-color temperature light. I wonder if this will eventually be done city-wide, and if so is it partially because of the increasing number of HID headlights. Or perhaps it may just be that metal halides finally have decent color rendering and efficiency as good as high-pressure sodium. Most of the sodium streetlight assemblies are 20 to 30 years old, and probably need to be replaced soon anyhow. I'm guessing the city will replace them with metal halide, or perhaps they'll wait until LEDs exceed sodium vapor efficiency. Regardless of when and if they'll be replaced soon, I'm sure they'll use something giving white light as the sodium vapor lights were almost universally hated when they were put in. I think the higher lumens per watt is the sole criterium that started the changeover in the early 1970s from the older mercury vapor.

 

[i]

I don't like metal halide street lights and HIDs. Sodium vapor is just fine. It's night-time ... it's not supposed to be like Texas on a clear summer's day.

Sodium vapor lights give off light at very specific frequencies. Those frequencies are relatively easy to block with the right filter. Metal halide and whatever they use in those HIDs gives off light at all kinds of frequencies. You can't block their effects without also blocking the light frequencies of whatever you're trying to look at. Like the Ring Nebula (M57) for example.

It won't surprise me if someday kids will grow up in even small towns having never seen a single star at night, let alone anything like a simple nebula.

Metal halide and HIDs ... I don't think they're worth the price, personally.

 

[Buck]

I must agree with i, the artificial light produced at night has become ridiculous. Add to this the Xenon and HID headlights, and being out at night is miserable. Give me darkness, give me dimmer switches; give me incandescent bulbs! I would like to walk out of my front door, look at the sky, and see the beautiful celestial lights in all of the glory. I would like to enjoy the darkness of a new moon, and the brightness of a full moon. I would like to sleep in my bedroom at night in complete darkness and silence.

I know, I know, it’s all about me, but since others were shoveling forth their humble opinions, I thought I’d toss mine in as well.

 

[sechs]

I'm sure that there's a great expanse of nothing in particular that would suite you well.

If anything, you could move over here to Nebraska. Pitch dark at night in most places....

 

[Buck]

I'm sure that there's a great expanse of nothing in particular that would suite you well.

If anything, you could move over here to Nebraska. Pitch dark at night in most places....

 

[jtr1962]

Sodium vapor lights give off light at very specific frequencies. Those frequencies are relatively easy to block with the right filter. Metal halide and whatever they use in those HIDs gives off light at all kinds of frequencies. You can't block their effects without also blocking the light frequencies of whatever you're trying to look at. Like the Ring Nebula (M57) for example.

It won't surprise me if someday kids will grow up in even small towns having never seen a single star at night, let alone anything like a simple nebula.

This is being addressed in the newer metal halide streetlight designs which are designed to eliminate light pollution while putting more light on the street where it belongs. This is one of my complaints as well because on most nights in NYC you can only see a few hundred stars. Sodium vapor is old technology that won't be used for the next generation of streetlights. As I said, most people hate it or any other type of monochromatic lighting. Colors render horribly and the yellowish light doesn't seem as bright as an equivalent amount of halide light. Besides that, they seem to put drivers to sleep. An ideal situation would have the streets lit up like a ball park while the sky stays dark.

I would like to sleep in my bedroom at night in complete darkness and silence.

Agreed on the silence part-I hope completely silent computers come out soon. My bedroom is fairly dark at night with no much stray light so that's no problem. A lot of times I sleep with the light on anyway-I'm used to sleeping in the day and can't always get to sleep in a dark room.

 

[blakerwry]

i dont imagine it's ever quiet in NYC

 

[jtr1962]

Generally, you'll still hear the odd ambulance, police car, or helicoptor at 3AM, but it does get pretty quiet around here late at night. Besides, the double pane windows seal out sounds pretty good. My biggest complaint is the noise from the damned airliners.

Speaking of HIDs, anyone ever consider putting one in the back window of your car? My brother used to have a fog light in his back window that he used to get back at idiots who cut him off or otherwise drove stupidly. With the huge increase in the number of idiots on the road these days, I think a rear-facing HID would be very useful, and even more blinding. I'm seriously considering putting a few battery-powered strobes on my bicycle for similar reasons. Only caveat is that I wouldn't use them if someone is behind or next to the person I'm pissed off at. I don't need to hurt innocent bystanders in the process. As for the idiot driver, think of it as Darwinism in action. :mrgrn: I don't think anyone my brother flashed actually had an accident because of it, but a few had to pull over until the spots went away. At least that kept them away from him.

A while back I heard about someone who made a device that sent a huge EM pulse away from their vehicle. This had the advantage of disabling the vehicle but not harming the driver. The driver retained control while the vehicle harmlessly coasted to a stop. Once again, don't use when other vehicles are in range. This is also a good tool if you're being pursued by law enforcement (don't think it would work on helicoptors, though). The electronics in modern vehicles are their Achilles heel. I don't think the EM device had much effect on older vehicles with no computers (perhaps it stalled the vehicle temporarily). Modern vehicles are completely fried (every transistor in the vehicle). In fact, the repair cost is generally so high that insurance considers the vehicle totaled.

 

[Buck]

A while back I heard about someone who made a device that sent a huge EM pulse away from their vehicle. This had the advantage of disabling the vehicle but not harming the driver. The driver retained control while the vehicle harmlessly coasted to a stop. Once again, don't use when other vehicles are in range. This is also a good tool if you're being pursued by law enforcement (don't think it would work on helicoptors, though). The electronics in modern vehicles are their Achilles heel. I don't think the EM device had much effect on older vehicles with no computers (perhaps it stalled the vehicle temporarily). Modern vehicles are completely fried (every transistor in the vehicle). In fact, the repair cost is generally so high that insurance considers the vehicle totaled.

Wouldn't do much against my 1982 Diesel. The only way to stop the engine is through a vacuum system, not electronics. If the vacuum system fails, there is a lever in the engine compartment labeled "STOP".

 

[e_dawg]

Those are similar to GE's Reveal bulbs. Both have a blue neodymium coating to bring the color temperature up a bit (this absorbs some light and brings efficiency down a bit). [...] And the light still looks yellowish compared to fluorescent even though it is whiter than regular incandescents.

I just bought a pack of GE Reveal 100 W bulbs. I quite like them. IMO, they look like the Sylvania Silvestars with a slightly pinkish-purple tint when you first look at them, but the light they throw is fairly white and sunlightish IMO. I'm guessing they are somewhere around 4000 K. In comparison to the 2700 K standard incandescent right next to it, the regular incandescent seems very yellow. They also look a bit like the cool white compact flourescents, although with a little better spectral balance IMO.

It is interesting that the luminosity is so much lower with the neodymium coating: 1352 lumens @ 100 W, compared to 1690 for GE's regular Soft White bulb -- a 20% reduction. It certainly doesn't look noticeably dimmer.

I really didn't answer this part of your question but it depends on the phosphors used. Some daylight tubes actually have better CRI than daylight CFLs. The ones I was using in my bedroom until yesterday had a CRI of 85 (Philips Alto brand Daylight Deluxe)...

I was finally able to track down full spectrum flourescent tubes at Canadian Tire. They sell the GE Sunshine tubes for something like $7 CDN a pop ($5.25 USD). They are 5000 K and a CRI of 90... that sounds just about right for the home office and rec room. I see that their Flourescents datasheet also lists the GE Natural tubes at 3700 K and a CRI of 90... that sounds like it would work well for the kitchen and bathroom. Only problem (besides the cost of replacing all those tubes and finding a store that carries those 'natural' tubes) is that their luminosity is ~30% lower than standard 40 W CW tubes.

Check out the datasheets here: http://www.gelighting.com/na/litlib/pr_consumer.html

Turns out that I've been suffering with the mass market GE Cool White Watt Miser tubes with a CRI of 60 and the Daylight tubes I had been using had a CRI of 75. No wonder I hate flourescent lighting...

 

[jtr1962]

It is interesting that the luminosity is so much lower with the neodymium coating: 1352 lumens @ 100 W, compared to 1690 for GE's regular Soft White bulb -- a 20% reduction. It certainly doesn't look noticeably dimmer.

Higher CCT light sources seem brighter for a given luminance level. I noticed this comparing a bike headlight modified with white LEDs to a stock one with a halogen bulb. As best as I could calculate, driving the LEDs at 1.7W produced the same lumens as the halogen bulb at 2.4W (yes, the LEDs are somewhat more efficient) but everything looked probably twice as bright (very subjective) under the LEDs.

I was finally able to track down full spectrum flourescent tubes at Canadian Tire. They sell the GE Sunshine tubes for something like $7 CDN a pop ($5.25 USD). They are 5000 K and a CRI of 90... that sounds just about right for the home office and rec room. I see that their Flourescents datasheet also lists the GE Natural tubes at 3700 K and a CRI of 90... that sounds like it would work well for the kitchen and bathroom. Only problem (besides the cost of replacing all those tubes and finding a store that carries those 'natural' tubes) is that their luminosity is ~30% lower than standard 40 W CW tubes.

I have those exact same Sunshine tubes in my workroom (I paid $5.99 US), and the only drawback is the lower luminosity. For full-spectrum 40W tubes giving 3600 lumens, try here if they ship to Canada. I'm using their T-8 tubes and I'm quite satisfied. When my GE tubes go I plan to order the T-12 tubes from them. Only thing I would recommend is to order in multiples of 6 since the shipping cartons hold 6 tubes. Although I prefer 5000K the local Pathmark lit up with 3500K tubes (only I would notice these things ) actually looks fairly good IMO. I can personally be happy with any CCT from about 3500K to 6500K as long as the tubes have a good CRI. However, I rarely see tubes with a CRI above about 85 and a CCT outside of the 5000K to 6000K range. I guess those Natural tubes are an exception, and would probably make a decent choice for any non-work area. I would personally stick with 5000K tubes in a kitchen, but that's just my preference.

Turns out that I've been suffering with the mass market GE Cool White Watt Miser tubes with a CRI of 60 and the Daylight tubes I had been using had a CRI of 75. No wonder I hate flourescent lighting...

When I do a little digging around I find almost everyone I've met who says they hate fluorescent light uses similar mass-market tubes with poor CRI and a magnetic ballast prone to flicker. I'm not thrilled with that type of fluorescent lighting myself (although I still like it better than incandescent), which is why I've been studying the problem and changing tubes and fixtures like crazy the last year. BTW, my bedroom looks great in 5000K. I notice the dust even more. :mrgrn: Seriously, though, I don't know whether it's the much higher light levels or the change to an electronic ballasted fixture with 5000K tubes, but I feel more alert now and don't get as tired staring at my monitor for extended periods. Only problem is the glare but I think a home made glare shield will solve that problem.

 

[e_dawg]

Well I have to thank you (and company) for shedding some light on the situation, because I would have still been in the dark with respect to my lighting choices if I didn't read about superior options here. (sorry about the puns... they were just too easy)

The unfortunate part of this, however, is that I will never be able to buy another light bulb or flourescent tube without worrying about the colour temp and CRI of the lighting product in question :evil: What was that they said about ignorance and bliss?

 

[jtr1962]

You're quite welcome, e_dawg, and I'm glad the time I spent studying lighting for my own purposes this past year came in handy to help others with similar problems.

One thing you may wish to consider if you're in a position to change out fixtures is an upgrade to electronic-ballasted T-8 fixtures. This increases system efficiency and avoids 60Hz flicker problems. The increase in efficiency can be dramatic, especially if you're using relatively low output tubes like the Sunshine tubes. For example, a magnetic ballast designed to drive 2 T-12 tubes to full power will have an input power of maybe 95 watts. The two GE tubes will put out 4500 lumens total, so the system efficiency will by 47.3 lm/W.

Now consider an electronic ballast driving T-8s. My new bedroom fixture has a ballast factor of 0.8, meaning it drives the tubes to 80% of full brightness. Light output (4 tubes) is therefore 4x2950x0.8, or 9440 lumens. Input power is 102 watts, so system efficiency is 92.5 lm/W, or nearly twice that of the magnetic-ballasted system. Of course, the example is skewed because I used low luminosity full spectrum T-12 tubes even though better ones are available. However, even using the 3600 lumen full-spectrum T-12 tubes I mentioned earlier, system efficiency with a magnetic ballast comes out to 7200/95, or 75.8 lm/W. This is still 18% less than the T-8 fixture, and this is using the best tubes made. Besides, as I mentioned, electronic ballasts eliminate flicker, which is the main thing that causes people to dislike fluorescent lighting (poor CRI of mass-market tubes is a close second), and that alone is enough of a reason to change fixtures. Even if changing fixtures is not an option for you, I thought it would be a good idea to give you this information. If you're handy, a more cost effective option, especially if the fixtures are in good condition, might be to just change out ballasts. T-8 tubes use the same type of sockets as T-12 tubes. You can get decent T-8 ballasts on eBay for $10 to $15 each. It seems T-8 ballasts are also able to run T-12 tubes even though this isn't recommended, and there are some that can drive both. In fact, Home Depot has a $7.95 shoplight with such a ballast (SKU 140-905). This might be just the ticket for you if you have a Home Depot nearby.

Here is an interesting article (complete with pictures) on how to overdrive tubes using the ballast from this shoplight. I tested it out, and it does work. I don't plan to build any overdriven fixtures, but it's good to know if I ever have the need for a shoplight putting out ~10,000 lumens (with only 110 watts of power!) I can.

 

[Buck]

Here is an interesting article (complete with pictures) on how to overdrive tubes using the ballast from this shoplight. I tested it out, and it does work. I don't plan to build any overdriven fixtures, but it's good to know if I ever have the need for a shoplight putting out ~10,000 lumens (with only 110 watts of power!) I can.

Good information jtr, and nice link. I just might have to give that overdrive stuff a try.

 

[ddrueding]

JTR,

That's a great article. Just curious, does Home Depot also carry "daylight" rated T-8s? Any particular brand you would reccomend? I plan on playing with this "overdrive" thing for a new light to go over my workbench (I've found the higher color temp keeps me more awake ).

 

[jtr1962]

Just curious, does Home Depot also carry "daylight" rated T-8s?

The bad news is that they don't but the good news is that the shoplight I mentioned can run T-12s. In fact, it even says on the ballast that it can run T-12s. Home Depot has Philips Alto T-12 Daylight tubes rated at 2325 lumens and a CRI of 84 in a two-pack for $5.99. Very nice tubes. I was using these in my bedroom prior to the fixture change. They also have plain cool white Philips T-8 tubes (4100K, 2850 lumens, 78 CRI) at 2 for $3.99 or in a box of ten (don't remember the price). Based on the figures in that article, rewiring the shoplights would overdrive the T-12 tubes by about 30%, so you would be getting around 6000 lumens total with the T-12 daylight tubes. GE definitely does make some nice T-8 daylight tubes (look for F32T8/SP65 on the tube) rated at 2700 lumens and 75 CRI (good enough for the workbench) but I'm not sure where to get them. If you can find them then you should be able to get close to the 10000 or so lumens I mentioned in the daylight color temperature. Or you can always order from the place I linked to a few posts back. Those are 5000K but in actual use the color temp seems a little hgher, and you can't beat the CRI of 91. BTW, a higher color temp keeps me more awake as well.

Since my mother is into plants I might have an excuse to make a few overdriven fixtures myself for seed starting. Sounds like a lot of fun, and I'm curious how long the tubes last being overdriven. According to the article, several people have gotten at least 4000 or 5000 hours with no burnouts. That's certainly adequate for occasional workbench or seed starting use. Since the T-12 tube is only mildly overdriven (30%) it should last close to the rated life (usually 20000 hours). I'd be willing to guess that T-8 tubes will last at least one-third to one-half the rated life at the 70% overdrive level of the rewired fixture. BTW, the overdriven T-8 tubes do get somewhat hotter than normal, but not severely so. They are cool enough to touch(maybe 130°F-140°F), but you probably couldn't keep your hand on one for too long.

 

[e_dawg]

One thing you may wish to consider if you're in a position to change out fixtures is an upgrade to electronic-ballasted T-8 fixtures.

Yes, I will definitely consider T-8 ballasts when I move to a new house; the condo unit I just bought is devoid of any flourescent lighting fixtures. Mostly halogens and regular A-type incandescents (which I will replace with GE Reveal bulbs before I replace them entireley -- probably with halogens). I can't say that I would consider replacing any of the incandescents with flourescent lighting because it really wouldn't match the decor (dark hardwood floors, cherry cabinets).

The study and bedroom do not have light fixtures installed, so I am actually considering putting in a T-8 ballast, but I am leaning away from that option because it would wash out the computer screen a bit (what is your opinion on that? Every office environment I have worked in with flourescent lighting required that I crank up the brightness and contrast to be able to see the screen properly, and even then the contrast wasn't nearly as good as it was at home, where my computer area is lit by an incandescent that is not nearly as bright).

As for the bedroom, flourescent lighting would be just plain wrong IMO...

 

[jtr1962]

The study and bedroom do not have light fixtures installed, so I am actually considering putting in a T-8 ballast, but I am leaning away from that option because it would wash out the computer screen a bit (what is your opinion on that? Every office environment I have worked in with flourescent lighting required that I crank up the brightness and contrast to be able to see the screen properly, and even then the contrast wasn't nearly as good as it was at home, where my computer area is lit by an incandescent that is not nearly as bright).

As for the bedroom, flourescent lighting would be just plain wrong IMO...

I'm having that glare problem right now as I mentioned previously, although a polarizer or glare shield should solve it (and would in most brightly lit offices). I didn't have glare prior to the fixture change even though that was still fluorescent lighting. A fixture with a dimming ballast would also work, but those are hard to find and too costly. What size is the study? You can light a room not too brightly by choosing a one or two tube fixture, and thus avoid the glare problem. Or you can have two or more independently switched fixtures where you can have very bright lighting at will but dim it down for when you're using the computer. Believe it or not, despite the glare, with the lack of flicker and higher lighting levels I find that I'm less fatigued after using the computer for long periods than before. After a few hours, my eyes learned to adjust for the glare. I still plan to buy a polarizer as I couldn't imagine editing pictures on a washed out screen like this.

Fluorescent can work in any room IMO. It's just a matter of getting the right fixture and tubes. I would imagine for a bedroom or living room with a wood decor a lower lighting level and a lower color temperature (3500K) would work better. There are all types of fluorescent fixtures, including some with wood designed to match traditional decors. And some mount flush in the ceiling so as to be totally unobtrusive. My only recommendation is that unless space or appearance constraints prevent otherwise, go with fixtures using four-foot tubes. Other sizes are harder to find, especially in certain color temps, and cost more.

 

[ddrueding]

Out of curiosity, any guess on the CRI of the CFLs @ home depot? Those are the only ones I have and I'd like a benchmark (comparing to the T-12s @ 84 you mentioned). Online ordering is not an option currently as I am without credit card (or any other location-aware ID....long story)

 

[jtr1962]

Out of curiosity, any guess on the CRI of the CFLs @ home depot? Those are the only ones I have and I'd like a benchmark (comparing to the T-12s @ 84 you mentioned). Online ordering is not an option currently as I am without credit card (or any other location-aware ID....long story)

I've looked at a lot of CFL comparisons, and 82 seems to be the CRI of almost all of the recent ones. Based on comparing my desklight CFL to the tubes, I would say that 82 is a fair guess. Reds rendered very slightly better under the 4-foot tubes than under the CFLs, but other than that I didn't notice much difference.

I'm surprised you don't have a CC. That must be horrible. Do you know anyone locally who could order online for you and then take cash on delivery?

 

[ddrueding]

I'm surprised you don't have a CC. That must be horrible. Do you know anyone locally who could order online for you and then take cash on delivery?

No CC is not the ideal, but for more major purchases, I do have a company AMEX I can use. But for stuff like this, I'm not up for the hassle. I've found quite a few vendors that still do COD to my PO box.

 

[Pradeep]

How do you do COD to your PO box? Using USPS and you pay the post office before they give you the package from behind the counter?

 

[ddrueding]

How do you do COD to your PO box? Using USPS and you pay the post office before they give you the package from behind the counter?

I have an account with the service that handles my box, they cut money orders on the spot and I pay in cash when I pick up the package. Quite handy, considering the complete anonymity of the whole thing.

 

[sechs]

Just to be clear, you don't have a post office box... just a mail box at a store.

 

[The_Giver]

Just to be clear,...

Very important, this is, in a thread about light bulbs.