Energy Efficient Alternative to 40 Watt (F40) T12 Fluorescent Bulbs?
Last Post 26 Apr 2013 08:49 PM by jonr. 26 Replies.
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Bill NeukranzUser is Offline
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13 Jul 2012 09:34 PM
Is there a cost effective, energy efficient alternative to 40 Watt T12 (F40T12) bulbs?

I've got about 20 of these in my house.

I'm OK with continuing to use fluorescent bulb technology because these T12 bulbs all provide indirect lighting - none of the actual bulbs are physically visible. And in fact fixture housing is not of concern because none of the fixtures too are visible.

Would appreciate the counsel of those of you who are familiar with this subject.

Many thanks, and best regards,

Bill
Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
Bill NeukranzUser is Offline
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13 Jul 2012 09:56 PM
Interestingly, after posting this subject, just two subjects down the list, is "Linear Lighting." Wow! What good fortune!

I'm wanting to emphasize lumens per watt efficiency. Looks like I need to look hard at T8 or T5 bulbs.

Best regards, Bill
Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
ICFHybridUser is Offline
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13 Jul 2012 10:30 PM
none of the actual bulbs are physically visible.
I just finished doing a bunch of mockups in my new kitchen and the T5/T8 solutions are really the way to go if you have an indirect setup. Some of the newest LED stuff is right in there if you are trying to do something with a tight profile, but it is really, really hard to find anyone who knows what they are doing with those. Even the company reps are kind of lost on how to work them well. Right now, I'd say go with the fluorescent tubes, but plan for upgrading slowly. That way, you will be able to learn about what they do in your environment.
whirnotUser is Offline
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13 Jul 2012 10:43 PM
Make sure the fixtures you replace them with have electronic ballasts, especially if they are multiple bulb fixtures. then if you have too much light you can remove a bulb or two and reduce Energy. With standard ballasts the energy use remains the same.

T5 are much more efficient than T8, so would be preferable. Also be aware there are many colors (kelvin Rating) so you can adjust the color of the lamp.

And a bit of trivia not well known, you can easily identify T5 vs t8 vs t12. it is the diameter of the bulb in 1/8 inches. (5/8, 8/8, 12/8)
Bill NeukranzUser is Offline
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13 Jul 2012 10:57 PM
Thanks!

Looks like I can simply relamp my T12s with T8s, as the end tube pin spacing is the same. Looks like it's about a 10% energy savings. Not sure yet if there's additional savings to be had if I also change out the magnetic ballasts to electronic.

Looks like I can get a 50% energy improvement if I instead go to T5s, but, these have a different end tube pin spacing and thus requiring a different fixture. Or at least replacing the end pin holders, since I'm using simple out-of-view linear bare-bulb fixtures. My guess is with the T5s I've also got the expense of replacing the magnetic ballasts.

Best regards, Bill
Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
Bill NeukranzUser is Offline
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13 Jul 2012 11:22 PM
This is a pretty interesting subject! I enjoy learning new stuff.

Looks like I can get 50% T5 improved efficiency versus my F40T12s by replacing the bulbs with F32T8 and replacing with one lamp F32T8 electronic ballasts.

Best regards, Bill
Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
BrockUser is Offline
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14 Jul 2012 07:02 PM
Keep you eye on the power used. Many of the older ballast, both magnetic and some electronic will just put out a flat wattage regardless of the lamp used. So if you throw a 32w T8 in there it may still be consuming 40w. The ballast are really what starts the power consumption and can push more in to a lower wattage tube. I have 0* start 4 foot T8's with dual 32w in the garage. The unit pulls 100w with both tubes and 80w with one tube. But they start at any temp For the cost I would stick with T8's or T5's.
Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1.8kw solar PV setup, 3400 sq ft
Bill NeukranzUser is Offline
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14 Jul 2012 08:32 PM

Thanks, Brock.

I'm confused, though.  If you have a fixture with two F32T8 bulbs, then why does it consume 100 Watts instead of 2 * 32 = 64 Watts?

Does the ballast consume the remaining amount, i.e. 36 Watts?  And if so, is it a magnetic (versus electronic) ballast?

Many thanks!

Best regards,

Bill

Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
BrockUser is Offline
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25 Jul 2012 10:34 AM
From my experience the ballast uses some of the power but it somehow pushes more power in to the lamp no matter it's rating. Sort of like pushing a 120v incandescent bulb at 140vac instead of 120vac, it's brighter and uses more power but won't last as long. I also have some "green" shop light and it uses 65w no matter what 4 foot tubes I put it in, I tried the stock 40w, 32w and even a 28w and the kill-a-watt said 65w no matter which one was in there. the 28w tubes looked the brightest, but there wasn't much difference.
Green Bay, WI. - 4 ton horizontal, 16k gallon indoor pool, 1.8kw solar PV setup, 3400 sq ft
jonrUser is Offline
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25 Jul 2012 08:33 PM
IMO, the most important metric is "$ per year". Otherwise you might start replacing those closet bulbs that will never ever pay back.
Bill NeukranzUser is Offline
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26 Jul 2012 01:38 AM
Posted By Brock on 25 Jul 2012 10:34 AM
From my experience the ballast uses some of the power but it somehow pushes more power in to the lamp no matter it's rating. Sort of like pushing a 120v incandescent bulb at 140vac instead of 120vac, it's brighter and uses more power but won't last as long. I also have some "green" shop light and it uses 65w no matter what 4 foot tubes I put it in, I tried the stock 40w, 32w and even a 28w and the kill-a-watt said 65w no matter which one was in there. the 28w tubes looked the brightest, but there wasn't much difference.

Yep, I'm learning that ballasts must be matched to tubes, regardless of being magnetic or electronic.  Like you noted, otherwise, in may cases you can put in different bulb sizes, with no change in ballast, and the power consumption is nearly the same.  And in many cases the (now) improperly matched bulb burns out much faster.

And I'm learning that even if you decide to change out the ballast to accommodate a more efficient technology tube, you may even need to change out the tube clips on each end.

My project has expanded.  The mission now is to replace all magnetic ballasts with electronic ones.  In some cases I'm learning that it's more cost effective to simply throw away the whole (old) fixture, and simply replace it with a new one (i.e., F40T12 to F26T5 strip fixtures).  In other cases, I need to figure out what electronic ballast to use to replace the magnetic one, and keep the same bulb (i.e. 39 w Biax CFL).

Best regards,

Bill
Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
s.kellyUser is Offline
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06 Aug 2012 10:54 AM
Energy usage of the magnetic ballasts is higher, but the electronic ballasts do not last nearly as long. I have seen decades old mag ballasts still working. For a small energy savings you may spend alot more in ballasts over time. I would personally probably leave old ones alone until they fail.
Dana1User is Online
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06 Aug 2012 03:20 PM
The energy savings over the lifecycle of an electronic ballast will pay for the electronic ballast AND installation labor many times over, even at rates as low as 7 cents/kwh. Getting rid of the magnetic ballast ASAP is the right thing to do except for installations where the hours per year of operation are limited.

For fixtures in daily use you don't even have to think about it.

If you have a lot of ballasts to swap, buying electronic ballasts in cases of 10 cuts cost dramatically (and buying them by the case surplus on the big web-auction site can cut the cost even further.)
Bill NeukranzUser is Offline
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06 Aug 2012 11:27 PM
Thanks Dana.  I've completed phase 1 of my 'replace all magnetic with electric ballasts' project.

I purchased from eBay a quantity package of electronic ballasts for my F39BX fixtures, clipped out the magnetic ballasts from my existing fixtures, and used the existing wires to connect to the new electronic ballasts.  Ended up converting these F5 bults from rapid to programmed start - didn't need to change out each fixture's (single) bulb holder.

The elimination of no noise / hum is really nice.

Next phase is to address six F40T12 (4') two bulb strip fixtures.  In this case it looks to be less expensive to simply replace the entire strip fixtures, versus replacing the magnetic ballast and the end clips and the bulbs in each fixture.

I'm keeping my eye out for a reasonable purchase price for the fixtures - nothing on eBay at the moment.

Phase 3 is to address six F40T12 (4') one bulb strip fixtures.  I think it's the same solution.

Phase 4 is to address three F32T12 (3') one bulb strip fixtures.

And Phase 5 is to address a few misc fixtures - a 3' T8 covered fixture and a fluorescent bulb over the stove cooktop.

Best regards,

Bill
Energy reduction & monitoring
American Energy Efficiencies, Inc - Dallas, TX (www.americaneei.com)
Example monitoring system: www.welserver.com/WEL0043
inspiredledUser is Offline
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04 Mar 2013 11:35 AM
T5 are much more efficient than T8, so as far as energy saving I would choose those. Another thing to take into consideration is the temperature of the lighting. Many times people do not realize that LED lights have a pretty big variety of white light temperatures, both cool and warm. Because of this however, it should be fairly easy to match your current lighting color, if that is what you want to stick with.
Dana1User is Online
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04 Mar 2013 06:23 PM
T5s are great, but their margin over T8s are a bit less than "...much more efficient..". It's not 2x, or even 1.2x from a lumens/watt point of view, and the selection of T5 tubes with CRI>85 are pretty limited (but getting better.)
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30 Mar 2013 11:35 AM
I've spent many hours boning up on T12 improvement options for a light commercial client and my research suggests Dana is correct. T8 is mainstream with commodity pricing and many many options as to start methods, CRI, lumens per bulb, ballast factors, color temperatures etc.

T5 seems to marginally more efficient in some applications but at higher cost and fewer options .
Curt Kinder

The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill

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jonrUser is Offline
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30 Mar 2013 02:54 PM
I'd say the same for LEDs. Not there yet in terms of price vs efficiency. My understanding is that for all lights other than incandescent, it is the ballast/regulator that controls the wattage - not the bulb/tube/LED itself.
Dana1User is Online
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01 Apr 2013 07:09 PM
Yup- it works as a system- the tube or LED is just the critical component being controlled. Both will affect efficiency though- you can't get much lighting efficiency out of the worlds-crummiest tube phosphors or low-efficiency LED elements. With fluorescent tubes the tube itself has to be designed for the ballast it's using though- even though you can put a T12 into some T8 fixtures, the impedance of the bulb is different enough to not regulate well or hit it's efficiency numbers. (In some instances it can damage the ballast.)

LEDs make some sense in locations where replacing a CFL might be onerous (say 24' up on the Great Room ceiling) or where you'd have to pay somebody for replacements. In new construction the cost-adder of using an LED-only fixture isn't huge in the total installation cost, especially if you can get them at wholesale (or subsidized retail) pricing. Be sure you get something you like though- it's lifecycle may be longer than your siding or windows.
jonrUser is Offline
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11 Apr 2013 02:05 PM
Philips announces 200 lumens/watt:

http://www.engadget.com/2013/04/11/philips-tled-lamp/

Cree hits 276 lumens/watt in the lab:

http://www.cree.com/news-and-events/cree-news/press-releases/2013/february/276-lpw
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