Basic Questions On Replacing T12 Fluorescent Tubes With T8 LED Tubes

[KenB64]

I plan to replace all my T12 fluorescent tubes with double ended ballast bypass T8 LED tubes ... and I have a couple of basic questions that I haven't been able to answer.

1. My T12's are all rated at 40W, 4100K and I have a mix of tubes with design outputs between 2200LM and 3000LM. I'm trying to figure out what LED tubes to buy that have a comparable output. It would seem that if I replaced ... as an example ... a 2200LM T12 fluorescent with a 2200LM T8 LED that I'd be good to go ... but I read that for an equivalent lumen output ... an LED tube will be brighter than a fluorescent tube ... which makes no sense to me ... lumens are lumens ... right? So ... what criteria should I be using and what T8 LED lumen rating should I be looking at to replace my T12 fluorescents?

2. In the garage I plan to go with 5000K T8 LED tubes and 4000K in the kitchen and bathrooms. If I went with 5000K in the house rather than 4000K ... would it be that big of a difference? From pics I've seen it doesn't seem to be ... but I've never seen it in person.

Thanks!

KenB64

 

[Duke74]

The 5000k will be a bit ‘whiter’ light than 4000k

 

[cybrdyke]

Depending on how old the T12's are, we equate them to 1700 lumen LED tubes. Well worn T12's can be even less. In garages and shops it's pretty common for folks to use a 2000 lumen LED tube to slightly improve what they had with fluorescents.
The reason for the difference in lumens between the two types is because LED puts all the light downward where it's needed and fluorescent wastes a bunch of light by shooting it up into the fixture.
As for color, it's a personal decision and there is no right or wrong. I dont normally offer an opinion. I'll make a small exception in your case. 5000k is on the "blue" side of white. It's fine for close work like in a garage. But it's not very comfortable or relaxing, which makes it a poor choice for inside a home. Even 4000k is uncommon in homes. Considering that the old incandescent light bulbs were 2700k, a very warm and relaxing tone, most people use 2700k or 3000k in their homes. The difference between 4000k and 5000k is very noticeable. Same for 3000k vs 4000k. YMMV.
Good luck,
CD

 

[KenB64]

The reason for the difference in lumens between the two types is because LED puts all the light downward where it's needed and fluorescent wastes a bunch of light by shooting it up into the fixture.

Isn't that a function of the beam angle? The tighter the beam angle the more light hits the surface. I've seen lots of LED tubes listed with beam angles between 240 and 330 degrees ... and I wonder how much the light hitting the surface is decreased.

My big problem is I can't see any T8 Led tubes in a real life setting. No one I know has them and all of the dealers I've visited have lousy displays or none at all.

KenB64

 

[BillK]

I replaced all of the tubes in my shop with these about a year ago:

https://keystonetech.com/spec_sheets/KT-LED43T8-96G-850-D.pdf

They have been great and the light difference from the old F96T-12s is amazing. Dont know where you are located but if you are anywhere nearby you are welcome to come take a look. I have tried taking pictures but they do not do it any justice.

 

[Bert_]

Isn't that a function of the beam angle? The tighter the beam angle the more light hits the surface. I've seen lots of LED tubes listed with beam angles between 240 and 330 degrees ... and I wonder how much the light hitting the surface is decreased.

My big problem is I can't see any T8 Led tubes in a real life setting. No one I know has them and all of the dealers I've visited have lousy displays or none at all.

KenB64

To narrow of angle is good either. Especially in a garage with strips. Narrow beam gives you a dark ceiling.

 

[BillK]

Forgot to ask earlier . . . . how tall is the ceiling ?

 

[cybrdyke]

Isn't that a function of the beam angle? The tighter the beam angle the more light hits the surface. I've seen lots of LED tubes listed with beam angles between 240 and 330 degrees ... and I wonder how much the light hitting the surface is decreased

KenB64

Yes. Beam angle is what I described without using the term. A fluorescent tube has a beam angle of 360 degrees. Nearly 1/3 of the light never makes it out of the fixture, so it's wasted. An LED tube delivers all of it's light, so very little is wasted. Typical LED tubes have a beam angle of around 165.
Beam angle is one of the most abused statistics in lighting. Many websites lie about this figure because they know that most people dont understand it. There are no LED tubes with a 330 degree beam angle. Any manufacturer claiming that is lying to you and should be discredited.
When you wonder about "light hitting the surface", you are correct. A wider beam angle means that the light directly below the source is going to be less.

 

[u2slow]

Reflector type fixtures redirected some of the 'wasted' uplight in the intended direction. A one-sided LED won't benefit from the reflector. Factor that in if it applies to your fixtures.

I would try a few different LED lamps before I committing to a whole house/shop worth.

 

[KenB64]

Dont know where you are located but if you are anywhere nearby you are welcome to come take a look.

Thanks for the offer! Unfortunately ... I'm located in California.

Forgot to ask earlier . . . . how tall is the ceiling ?

In the house the ceilings are 8 feet ... In the garage the ceiling is the roof line, so it's high ... but the cross rafters that I mount lights on is 8 feet ... and the walls are unpainted and the ceiling is bare wood.

There are no LED tubes with a 330 degree beam angle.

Here's an example of a tube that claims a 330 degree beam angle ... https://websvc.maxlite.com/api/items/documents/L13T8SE440-GB?type=datasheet ... Philips claims these are 240 degrees ... https://www.assets.signify.com/is/c...hting/united-states/20210222-15w-4000-pss.pdf Since LED's are flat it only makes sense that the beam angle would be around 180 ish ... but maybe these higher beam angles are the result of reflections inside the tube ... so maybe some of the light does go upward behind the plane of the LED ... but maybe it's not much. I think I need to review some polar plots to get a handle on this one.

I would try a few different LED lamps before I committing to a whole house/shop worth.

At least with tubes ... that's not proving easy. The local selection in the big boxes is very sparse ... isn't easy to find anything but non bypass tubes that require a ballast. Most available are low output tubes as well ... or require a 25 tube minimum purchase ... and often the pricing for individual tubes of any spec is extravagant. When I look online I find several tubes that I think might be suitable but are only available in lots of 25 or whatever. Some that I'd like to check out like the Philips MainsFit are only available wholesale and in lots of 25. Might be able to try an experiment with LED bulbs ... haven't looked at bulbs at all.

Thanks!

KenB64

 

[cybrdyke]

Here's an example of a tube that claims a 330 degree beam angle ... https://websvc.maxlite.com/api/items/documents/L13T8SE440-GB?type=datasheet ... Philips claims these are 240 degrees ... https://www.assets.signify.com/is/c...hting/united-states/20210222-15w-4000-pss.pdf Since LED's are flat it only makes sense that the beam angle would be around 180 ish ... but maybe these higher beam angles are the result of reflections inside the tube ... so maybe some of the light does go upward behind the plane of the LED ... but maybe it's not much. I think I need to review some polar plots to get a handle on this one.

The Maxlite is a lie. The Philips is accurate. Most of the legit manufacturers offer a 240d, which is achievable with the strip mounted to the top of the glass and a little help from the phosphors in the tube. 330 is not achievable (notice how the photometrics are missing?).
Beam angle is a specific scientific term and it's measured in labs on special equipment. The less scrupulous manufacturers will lie about these figures because they so rarely will be called out on them.

At least with tubes ... that's not proving easy. The local selection in the big boxes is very sparse ... isn't easy to find anything but non bypass tubes that require a ballast. Most available are low output tubes as well ... or require a 25 tube minimum purchase ... and often the pricing for individual tubes of any spec is extravagant. When I look online I find several tubes that I think might be suitable but are only available in lots of 25 or whatever. Some that I'd like to check out like the Philips MainsFit are only available wholesale and in lots of 25. Might be able to try an experiment with LED bulbs ... haven't looked at bulbs at all.

In my area, every single electrical supply house stocks them. They sell them individually.

 

[Bert_]

I like 240*. Gives you some uplighting.

 

[BillK]

At least with tubes ... that's not proving easy. The local selection in the big boxes is very sparse

KenB64

Ken,
Surely there must be some electric supply houses around ?? I bought my tubes at Rexel. I probably paid a little more but the peace of mind that they are literally walking distance from my business made it an easy decision.

 

[u2slow]

Thanks for the offer! Unfortunately ... I'm located in California.


In the house the ceilings are 8 feet ... In the garage the ceiling is the roof line, so it's high ... but the cross rafters that I mount lights on is 8 feet ... and the walls are unpainted and the ceiling is bare wood.


Here's an example of a tube that claims a 330 degree beam angle ... https://websvc.maxlite.com/api/items/documents/L13T8SE440-GB?type=datasheet ... Philips claims these are 240 degrees ... https://www.assets.signify.com/is/c...hting/united-states/20210222-15w-4000-pss.pdf Since LED's are flat it only makes sense that the beam angle would be around 180 ish ... but maybe these higher beam angles are the result of reflections inside the tube ... so maybe some of the light does go upward behind the plane of the LED ... but maybe it's not much. I think I need to review some polar plots to get a handle on this one.


At least with tubes ... that's not proving easy. The local selection in the big boxes is very sparse ... isn't easy to find anything but non bypass tubes that require a ballast. Most available are low output tubes as well ... or require a 25 tube minimum purchase ... and often the pricing for individual tubes of any spec is extravagant. When I look online I find several tubes that I think might be suitable but are only available in lots of 25 or whatever. Some that I'd like to check out like the Philips MainsFit are only available wholesale and in lots of 25. Might be able to try an experiment with LED bulbs ... haven't looked at bulbs at all.

Thanks!

KenB64

Online I have to buy quantities like that. At the electrical supplyhouse I could easily buy 1 or 2 LED tubes (I needed 36" ones).

 

[KenB64]

Surely there must be some electric supply houses around ?? I bought my tubes at Rexel. I probably paid a little more but the peace of mind that they are literally walking distance from my business made it an easy decision.

For sure ... there are LOTS of 'em around here ... but so far the ones I've checked are evidently doing so well they don't want my money.

 

[rsanter]

There are several reasons for what you are saying.
Lighting is both an art and a science.
You have:
Color rendering index
Color quality
Light quality
Color temperature
And more

Th amount of light a meter sees and the amount of like the eye perceives are different based on several factors
LED is better at the higher color temperature and that is also where the human eye perceives the light to be brighter