office lighting -- renovation

[the blur]

generally we do T8 lighting when renovating an office building. We wanted to get into the T5 stuff and biax, but many customers balk at the lamp price. What do you guys recommend for the 'green' office renovations?

 

[ActionDave]

I can't see any reason to do anything more than T-8's in an office.

 

[sgunsel]

I was recently in an office with T5 lamps. Each fixture had three lamps, no diffusers, and the center lamps were all removed - too bright. I think they are too bright for low ceilings. Maybe a good diffuser would help, but why not use T8?

 

[sameguy]

See your lighting rep. he can do a cost analysis for each, T5 for high areas T8 for normal.

 

[raberding]

green lighting

green lighting

many associate Green with LED...and Cree has a pretty cool 2x4 that is not too xpensive...http://www.creeledlighting.com/Products/Architectural-Troffers/CR24.aspx

 

[svh19044]

I would stick with the T8's for an office. As far as actual energy savings are concerned, assuming equal lamp life, there is minimal savings going from t8 to t5. It does not justify the initial price difference. They just aren't that much more efficient for an office.

I was recently in an office with T5 lamps. Each fixture had three lamps, no diffusers, and the center lamps were all removed - too bright. I think they are too bright for low ceilings. Maybe a good diffuser would help, but why not use T8?

T5's are too harsh of a light to use in most office areas as it's coming from such a small source. Some of the new retrofit kits are actually marketed just as you quoted, use less lamps for even more savings, delamping. That would be a retrofit kit though, perhaps not the same scenario as what you quoted.

 

[PEDRO ESCOVILLA]

full spectrum lamps. great for interior offices with out window spaces

 

[the blur]

We try to stay with the current technology. Customers like to hear about new and green. years ago, it was a 4 lamp T8 retrofit in a 2x4 layin.
Now we replace the entire fixture with a fancy 3 lamp T8 fixture, one of the open designs with a reflector. So going from 4 lamps to 3 lamps is more efficent.

But I see the future with T5's in every office. The fixture designs are out there, they just need to make the lamps more cost effective.

I did a few jobs with the BIAX, but they too were pricy.

 

[BullsnPyrs]

I'd reccomend T5 only in an direct/indirect fixture. Those are the 2x4's with a semi-circular perforated screen in the middle of the fixture. Most of the light is bounced of a white reflector and the efffect is really nice in an office.

 

[mbednarik]

Shoot for the led. I installed some lithonia LED troughers last summer. they had a lumen rating a little over half of the 4 lamp t8's that we were replacing. They dist. the light a lot better and we finished with the same FC levels according to my light meter.

 

[TNBaer]

LED? Thanks but I'll pass. It's just not more efficient than T8 at this point. I frequently go 2 lamp 28 Watt T8 with a .77BF ballast. If you're replacing a four lamp F34 system with new fixtures, I always hear that it's brighter. The quality of any 800 series T8 lamp is just that much better.

T5 isn't a little more efficient than T8, it's a little less efficient. I'm always amazed at how well this 30 year old technology holds up in most applications.

 

[the blur]

28 Watt T8

28 Watt T8

What type of problems can we expect when maintenance staff installs 28w T8's in 32w fixtures, and visa-versa? The local poco is pushing the 28w retrofits with rebates...

 

[steve66]

What type of problems can we expect when maintenance staff installs 28w T8's in 32w fixtures, and visa-versa? The local poco is pushing the 28w retrofits with rebates...

The sockets are different sizes, but I suppose if they are determined enough

For T5 vs. T8 there are a lot of variables. If your customer wants a standard prismatic fixture, give them a T8. If they want a newer looking fixture that helps reduce glare on monitors (I know, this is a problem that is going away with new monitors), there are a lot of very competitive T5 fixtures out there.

LED can be more efficient than T8 or T5 - and they are improving constantly.

Anything beats the old parabolic fixtures or the ones with louvers. It seems like the largely open design would be very efficient, but its just the opposite.

 

[BullsnPyrs]

The sockets are different sizes, but I suppose if they are determined enough

For T5 vs. T8 there are a lot of variables. If your customer wants a standard prismatic fixture, give them a T8. If they want a newer looking fixture that helps reduce glare on monitors (I know, this is a problem that is going away with new monitors), there are a lot of very competitive T5 fixtures out there.

LED can be more efficient than T8 or T5 - and they are improving constantly.

Anything beats the old parabolic fixtures or the ones with louvers. It seems like the largely open design would be very efficient, but its just the opposite.

The first 3 comments in order:

T5 is a different socket size. 28 and 25 watt T8 use the same socket as 32wT8 and T12.

True, direct indirect T5 fixtures look great and do a great job in an office enviorment. The cost of a new fixture makes the changeover have an extremely poor payback when compared to a 28wT8 relamp.

Payback is horrible and will be until LED is considerably cheaper or vastly more efficient.

And OP's origional question:

You need to look at the existing ballast to determine compatability with the 28wT8 lamp. The older the ballast the more likely you are to have compatability issues. Do you have master/slave fixtures in your facility? Ballast lead length can be a problem with the 28 watt lamp.

 

[TNBaer]

The first 3 comments in order:

T5 is a different socket size. 28 and 25 watt T8 use the same socket as 32wT8 and T12.

True, direct indirect T5 fixtures look great and do a great job in an office enviorment. The cost of a new fixture makes the changeover have an extremely poor payback when compared to a 28wT8 relamp.

Payback is horrible and will be until LED is considerably cheaper or vastly more efficient.

And OP's origional question:

You need to look at the existing ballast to determine compatability with the 28wT8 lamp. The older the ballast the more likely you are to have compatability issues. Do you have master/slave fixtures in your facility? Ballast lead length can be a problem with the 28 watt lamp.

All of the above is great!

Switching from 32 Watt T8 to 28 Watt or 25 Watt T8 is easy and painless. There may be some issues with ballast compatibility but from my experience these have been fewer than the lamp and ballast reps would have us believe. Lower wattage T8s have some issues with the cold and I do experience some striation with a certain percentage of lamps on initial startup; but these problems are few. Jump from a 700 series 32 watter to an 800 series 28 watter and the lumen loss is minimal and the gain in CRI is worth it. I stock exclusively 800 series lamps these days with lots of 28 Watters and use them with any ballast factor I desire. I can't sing the praises of the 28 Watters enough. I just stuck four of them in 8' Industrial Hoods with a 1.17 Ballast Factor and they looked fantastic (The old fixture was 3 - 60 Watt T12s).

Also, I just used some Sylvania 28 Watters and Philips 28 Watters on the same job and to a man we agreed with Philips was a little brighter.