LED bulbs and electric savings

maple1 said:

I'm pretty sure a flourescent fixture uses more juice than the sum of the bulb wattage. That's what I found when initially using my Effergy - but I forget now how much extra. I was chalking it up to the ballast using it. I ended up replacing two dual bulb 48" fixtures in my office, that were on usually 12 hours a day, with two ordinary dual socket fixtures with LEDs in them.

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Since I started paying attention, the last 15 or so tube fixture ballasts that I've installed all had a little table on them that listed input amperage for each bulb option. The tubes have a lumen label. The wattage of the tube is pretty meaningless.

Mainely Saws said:

Thanks Woodgeek . The LED bulbs that I have are 800 lumens so it looks like I would need to have 5 of these bulbs to replace the light output of one T12 75w but they would only draw about 52.5 watts compared to the 75w T12 tube . Do I have that right ?

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You don't calculate the energy use of a fluorescent light by using the watts printed on the bulb. You have to look at the ballast to find out how much power is consumed

With a Kill-o-watt and a twin tube florescent fixture rated for both 32W and 40W tubes, I measured just about 100W consumed regardless of use of T-8 32W or T-12 40W tubes. No energy savings at all. Maybe a higher quality ballast would do better, but not the ballast used in the inexpensive shop light fixture. I have replaced 3 of the old fixtures with an 11W round LED ceiling fixture, 4000K, and while not quite the same lumens the LED has brighter, easier to see lighting than the old florescent fixtures, and one of old fixtures I replaced with a similar 25W LED fixture.

I have a 16'x24' shop area( 9 1/2ft ceilings) with two 8' twin tube florescent fixtures for overhead light ( I have numerous point of contact LED lights on different machines ) so I'm thinking of taking those down & installing a number of standard round ceiling single bulb fixtures with 11w LED 's in them . Maybe use some type of reflective shroud to help .............

jebatty said:

With a Kill-o-watt and a twin tube florescent fixture rated for both 32W and 40W tubes, I measured just about 100W consumed regardless of use of T-8 32W or T-12 40W tubes. No energy savings at all. Maybe a higher quality ballast would do better, but not the ballast used in the inexpensive shop light fixture. I have replaced 3 of the old fixtures with an 11W round LED ceiling fixture, 4000K, and while not quite the same lumens the LED has brighter, easier to see lighting than the old florescent fixtures, and one of old fixtures I replaced with a similar 25W LED fixture.

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There ya go - it wasn't just me.

I was thinking maybe double the bulb wattage - but that's even more than that. I should go check again just for curiosity sakes.

jebatty said:

I measured just about 100W consumed regardless of use of T-8 32W or T-12 40W tubes. No energy savings at all. Maybe a higher quality ballast would do better, but not the ballast used in the inexpensive shop light fixture.

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I just changed out some old-style magnetic core/coil ballasts and they were rated for 120V/0.85A (102 Watts) to power a two F40 (40W) tubes, so there is 22W of loss in the old-style ballasts. Not sure what the electronic ballasts are rated for, but I would guess they have only 20% (or less) of the core/coil ballast losses.

I used these in the garage, each to replace a single 100W or 150W incandescent bulb, now with 2 x 60W equiv LED's. Better light, brighter, and far less watts.

The ballasts I replaced were in an older friend's flourescent tube kitchen light that was "home built" years ago using shop-light hoods with F40 tubes and magnetic ballasts. The person who built the light box sealed it up so tight the ballasts would get hot and turn off after 2 hours. I swapped them out with electronic replacement ballasts and problem solved - they will stay on all day and night now. Otherwise, I would not bother with keeping fluorescent tubes - would probably just go to LED strips now.

I have one shop light, two 32w T8 bulbs, electronic ballast, and on the Kill-o-Watt still 100w draw. This I use very little, on an occupancy sensor, so I haven't switched it out yet for LED. What I might and you might consider is stripping out the ballast and tubes and putting in LED strip lighting on your own with a 12v transformer.

jebatty said:

What I might and you might consider is stripping out the ballast and tubes and putting in LED strip lighting on your own with a 12v transformer.

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I was looking at that for some very old F40 hoods that I have. They are in a rarely used part of the basement and I might get around to retrofitting them one of these days.

Looks like a good bulb, price is good, not dimmable, 3000K (which I like better than 2700k) LED Woot

I would like to try out a few of these..... what is a good price point I should be looking for? I see HD has 60W Philips bulbs on sale for $4.50.

The price is good IMO, but pay attention to color 2700K and CRI 80. 2700K is much like incandescent but is too red for me. I like 3000 or 3200 for indoor and 5000K where bright white light is useful. I have not paid much attention to CRI but that may be important depending upon the application. HD has these for $8.97 on line with in store pickup in my location.

Picked up a few at HD today... they look nice. Way nicer than CFLs, and instant-on is great. I live in a mid-centry house with lots of beige, wood floors throughout, etc, so the warm/yellow is what I need. At $0.18/kwh replacing the last few incandescents around here should pay back in short order. Will probably grab a few more.

I want to re-lamp both of my farm tractors from Halogen to LED, preferably CREE and at least 6000 lumens per lamp with an effective range of 1/2 mile. I run 4 facing forward 2 facing rear and one facing to the right side. Any suggestions?

SidecarFlip said:

I want to re-lamp both of my farm tractors from Halogen to LED, preferably CREE and at least 6000 lumens per lamp with an effective range of 1/2 mile. I run 4 facing forward 2 facing rear and one facing to the right side. Any suggestions?

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No suggestions, but I'd like to know what you find. Unfortunately, my tractor is a 6v (built in 1951) which makes it even more interesting to convert to LED.

All the new ag stuff is LED now and my tractors are just prior to but I need to change them over as the big halogen lights I have are alternator killers. Been looking at the NH dealer (they have a good selection of LED's), www.tractorseats.com (also have a good selection) and www.superbrightleds.com (have a huge selection). I'm leaning toward CREE simply because they appear to be the best and longest lasting.

I'd go with HID but HID lighting requires heavy amperage on startup whereas LED don't.

I'm still running mostly CFL's. I bought a bunch of multi-packs when I moved into my current home, about a year before the popular Cree bulb debuted at $13 (now down to $8 in my area) with higher efficiency than most bulbs available at the time, and drove the whole market down into reasonably fast payback times (~2000 hours / ~2 years compared to incandescents). However, since I bought the CFL's, I'm going to use them up.

One place I do have an LED (the Cree) is by the front door, which gets left on during the short days in the winter so we have light when we get home from work. By a rough estimate, that bulb probably has close to 4000 hours on it in a little under 2 years, which isn't enough to payback versus a CFL yet, but I calculate I'm about $8 ahead compared to having used an incandescent over that time. If I had to pay New England electricity prices, it would be more like $25 ahead.

I was going to replace the basic ceramic screw bases in my garage with T-8 fluorescents, since they're cheap and the performance specs for those versus LED's are so close. However, with Philips and Cree both claiming they'll have LED's with efficacies as high as 200 lumens/W available soon, (Philips specifically said this year), I'm waiting to see if they can make good on their promises or are just blowing hot air.

WiscWoody said:

Natural sunlight doesn't look blue to me at all. 5000K bulbs look very bluish to me.

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That's because when you see sunlight, it's almost always the brightest thing you see by a long shot. Your eyes adjust automatically and very effectively to the dominant light source. When a daylight toned bulb is the brightest thing you see, there's usually other bulbs on, and they radically shift your perception.

The info above about fluorescent fixtures may explain my higher than expected electric consumption (so thank you!). We have changed out almost every light in our home to LED, got rid of the Fios power sucker boxes (one Tivo that is a bit better and Minis elsewhere), and lower power computers. Yet the power consumption is still above what I would expect. We work from a dedicated office in our home and I think the six dual-tube fluorescent fixtures in the office - on for about 9-10 hours per day 5 days / week and perhaps 2 - 6 hours some weekends - could be the culprit.

They are in a drop ceiling with those plastic covers under them to make them look halfway decent in the ceiling. Any suggestion for a relatively easy way to convert those to LEDs? I don't want to replace the whole ceiling.

These flat ceiling lights would be a possibility. Without the plastic cover, these are very flat and perhaps 2 in each fixture would work well. I pulled out the 2 x 40w fluorescent fixtures in our basement and replaced each with one of these, the least expensive ones: 3 - 11" ($27.99) and 1 - 14" ($39.99). We have a 4 x 24 fluorescent fixture in our hallway and I am going to remove the innards of that and replace with two of these ceiling lights inside the existing fluorescent can, but keeping the plastic cover for the existing fixture.

http://www.globalindustrial.com/searchResult?searchBox=&q=led+ceiling

Wilbur Feral said:

The info above about fluorescent fixtures may explain my higher than expected electric consumption (so thank you!). We have changed out almost every light in our home to LED, got rid of the Fios power sucker boxes (one Tivo that is a bit better and Minis elsewhere), and lower power computers. Yet the power consumption is still above what I would expect. We work from a dedicated office in our home and I think the six dual-tube fluorescent fixtures in the office - on for about 9-10 hours per day 5 days / week and perhaps 2 - 6 hours some weekends - could be the culprit.

They are in a drop ceiling with those plastic covers under them to make them look halfway decent in the ceiling. Any suggestion for a relatively easy way to convert those to LEDs? I don't want to replace the whole ceiling.

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I think running those lights here would amount to about $7/week.

@Wilbur Feral - I guess if the 100 W/pair figure cited above is accurate, the usage you describe is $15-20 a month. Also a typical desktop and monitor draws 150-200 W ($4-6/mo at 10 hours per weekday), and a smaller unit maybe around 100 W. Plus factor in your regular home usage. You don't have electric water heating, do you? That can add up fast.

Anyways, if your lights are the normal recessed troffers, you can get replacement LED troffers like these:
https://www.1000bulbs.com/category/2x4-led-troffer-fixtures/

Or keep your existing fixtures and use tubular LED's like these, but the lumen rating is a low lower than a regular T8, and for some brands (not the Cree), you have to rewire your fixture to bypass the ballast:
http://www.homedepot.com/p/Cree-TW-...48-17040FLW-BDG13-1C100/205737571?N=5yc1vZbol

Or wait a year or so and see if Philips was being honest when they said they'll have 200 lm/W tubular LED's out soon.

Thanks, all. Great info. Not so worried about cost as much as figuring out how to reduce waste. And HW is Geospring (love it).