Converting T12 kitchen lighting to T5 or T8?

[PandaBear]

I have a 4 tube 48" kitchen light fixture running off magnetic Ballast. It runs on average 5-8 hours a day depends on season, weather, etc. My understanding is T8 is the same socket and I can just replace the ballast to electric and get some easy savings, but it would be difficult to switch to T5 due to shorter tube length and smaller socket.

Is it worth trying to convert to T5 via adapter kit, or replacing the fixture, vs just to T8 and reuse the existing fixture? or is it just not worth any move and stay with T12?

My electric rate is about 12c/kwh at my current tier.

 

[JHZR2]

Time value of money?

48" tubes are what? 40W in T12?

What are they in T8? 35W?

Run some quick math in terms of your time, the conversion kit cost, etc.

Can a T8 run in a T12 slot without change of ballast?

Id probably wait until the lights fail or you remodel if the numbers arent compelling. A better ROI may be on a motion sensor or timer for the space so that the lights arent on so much.

 

[SuperDave456]

I think T12 bulbs are being "outlawed" from importation or manufacture by congress in 2014. I could be wrong, it may be 2016. T-8's are like 20% more efficient, T-5's are like 30% more efficient, but T-5's produce more glare and cost 2x the price of T-8's.
You can Google all kinds of neat articles on this topic.

4 years ago I replaced the T12 fixtures in my kitchen with new ones. I didn't know the above information until afterwards.
After looking at my choices I found that it was easier to replace them than to try to figure out the parts and wiring to fix the old equipment.

Could it of been done cheaper? Yes, but with also more research and headaches. I wanted lights in my kitchen pronto.

The magnetic ballasts have a hum, and begin to fail by taking time to turn on when cold. In my circumstance it sometimes took 5-10 minutes for the bulbs to turn on.
When I tore apart the fixtures to replace them I found that the magnetic ballasts were leaking a black smelly goo that had gotten all over the inside of the fixture.

The new electronic ballasts are instant on, even when cold, don't hum, and I'm on the same T-12 bulbs that I bought new 4 years ago. The lights in the kitchen are on probably 2-3 hours a night.

If I had it to do all over again I would go to T-8's just cause I will have to do that in the not so distant future.

 

[sparky123]

The socket ends in your fixture will accept a T12 or T8 linear fl. tube. The T12 tubes will be outlawed shortly, when I'm not sure. The magnetic ballast in a T12 fixture may hum and will not operate properly below 50 degree F. However, they will outlast an electronic ballast. Each has its plus' and -s's. If your fixture needs a new ballast then you'll have a hard time finding a magnetic ballest for a F40T12 fixture. You'll get an electronic ballast. It would make sense to get the F32T8 bulbs as they produce very nearly the same light output as the F40T12 bulb. You have choice of color temp. bulbs (warm white 2700K, 3500k, Cool white 4100K, Natural light 5000k, and daylight 6500k. Very important to get a bulb w/the high CRI (Color Rendition Index). Whether it makes sense for you to change your ballast and tubes out depends. 4x8watt= 32watt energy savings cost of ballast $20, Bulbs $4 ea. aprx. Forget the T5 conversion option IMO. If you want the T5's, get the complete fixture. (Not sure if you'll get the color temp choices w/the T5 bulbs as you would the T8 bulbs.)

 

[eljefino]

I'd go with the T8s and new electronic ballast. "They" say you save 15-30% over a magnetic ballast T12. T8s being smaller, IMO, give off more useable light because of more light reflecting around behind them etc.

You can get a fixture for about the price of a good ballast, but it probably won't be as well built as the one you have now. Are you emotionally attached?

 

[KeithS_NW_Ohio]

I replaced the dual T12 in my kitchen with an T8 3500k bulbs &
electronic ballast about 5 years ago, and never look back.
I also change out one of my garage T12's with T8 5000k bulbs.
Brighter than the other T12 4100k which is still there. Also lights up faster in the winter.

 

[tom slick]

I don't think you'd recoup any real money but they are more efficient, put out more light and you have more bulb color choices. I like 5000k bulbs for work areas and 3500k bulbs for living areas.

 

[PandaBear]

Efficiency (aka electric bill) is one reason, but that hum and cold start is another. I have no emotion to that generic builder special simple light (just a white plastic cover anyways), just trying to save time if a simple conversion kit to T5 is available at low cost instead of installing a new fixture and paint the ceiling for any newly exposed area.

Also would going from 4 F40T12 to say F35T8 or T5 means I can use fewer tube or shorter tube if I only need the same brightness (lumen)?

The problem with motion sensor based switch is that the switch is in the middle of the place, and if we turn on the kitchen light and stay in the family room for TV, it will turn off after a while because the switch can't see the family room.

 

[greenjp]

I conducted a pretty involved test on this subject for work over the last year. As others have said, forget about T5. They'd require some sort of retrofit kit or whole new fixtures.

Our test involved replacing 2' T12 lamps and magnetic ballasts with T8 lamps and electronic ballasts. The T12 lamps were the nominal 20W type, and the T8 were the nominal 17W type. On the surface this would seem to indicate a 15% saving. However, the electronic ballasts themselves are more efficient, and you may be able to use a lower ballast factor type to take advantage of increased initial light output, improved lumen maintenance, and the improved fixutre efficiency mentioned by eljefino. We found a total savings of about 39%.

Per some info from Philips and GE, a 4 lamp 4' T12 fixture with a single magnetic ballast can be expected to draw 172W and put out ~6,600 lumens (@60% fixture efficiency) at mean rated life (these numbers vary somewhat depending on exact ballast and lamp type but are useful for illustration). 4 T8 lamps on a "low" (0.77) factor ballast will draw 97W and put out ~6,300 lumens (@75% eff.) Go with a "normal" 0.87 factor ballast and you're at 109W and 6,900 lumens.

So, figure 60-70W savings. At 6 hrs/day, $0.12/kw-hr, you're looking at saving about $17/year. Probably not worth it from a pure dollars and cents perspective until the existing lamps or ballast start failing, but it maybe worth it just to get the less noisy ballast, improve the starting operation, and possibly go with a different color temp and higher CRI (definitely get 800-series lamps).

As to "de-lamping", it would be possible to go down to a 3 lamp setup if you use a "normal+" or high factor ballast, but then you'll have the potential for increased glare and the fixture might look weird. Probably not a good idea in the kitchen.

Definitely worth shopping around for the ballasts. Prices for the high efficiency types (GE UltraMax, Philips Advance, Sylvania Quicktronic) vary wildly from one vendor to another. We got them in volume for
jeff

 

[VNTS]

Your lowest cost solution would be to use the F32T8 lamps retorifitted into your fixture with a 4 lamp electronic ballast.
I designed the the filaments back in the day when I worked for Sylvania and did most of the development on the T8 lamps back in the 80's.

On the other hand, assuming you dont have garbage coolwhite lamps with lousey color renditon , I would just keep them myself.
They should last 20K hours give or take. The Octron stuff I worked on I tweaked the filaments and we life tested to median life of over 30K hours.

With switch to the FO32, your saving roughly 40Watts vs the F40T12, pay back would be a long time.

 

[DBMaster]

I have two recessed light housings in my kitchen. They had what I thought were shop lights inside of them. They did look the same. When the ballasts went out I installed two cheap shop light fixtures in the recesses. Guess what? They went bad in short order due to the heat. I installed two surface mount E27 bulb sockets in each recess and used compact fluorescent bulbs. In the future I can change to LED if I want to cut power consumption, but the 25W CFL's have been up there for three years now.

 

[eljefino]

Originally Posted By: VNTS

I designed the the filaments back in the day when I worked for Sylvania and did most of the development on the T8 lamps back in the 80's.

BITOG has an expert on everything!!! Cheers!

 

[Cujet]

Don't forget that you can get electronic ballasts for the T12's.

Also, if you need maximum light output, modern T12's have up to 4000 lumen capability. Whereas T8's are up to 3200 lumens.

Lumens per watt is not much different between the two, if electronic ballasts are used along with quality bulbs.

 

[PandaBear]

Great, what about reliability of T8 electric ballast these days? I think the ballast I have now came with the house and that makes it about 17 years old. How long would I expect it to last if it is not recessed into the ceiling and runs 6 hours a day on average?

 

[Cujet]

I have had zero T8 ballast failures, and I have a good number of fixtures, mostly in closets. I also have 7ea. T12 fixtures in my garage. I've converted some of those to electronic ballasts as the originals fail.

My house is 12 years old.

 

[VNTS]

Difficult to say on the lifespan of the electronic ballasts, any component [censored] out in them and there done.

I have some magnetic and triad utrad from back in the day pirated and at my folks house, about 1/2 have [censored] out, note these were infant electronic ballasts from development/evlauation I used them for their garage.

per your sitiuation, if your remodeling and want a nicer fixture for it and upgrade to the T8 with electronic ballasts and get nice lamps with color rendition and 3000K color.
Note life of any lamps is based on a 3 hr on 20 min off cycle, so lamps life is good.