# CF=T5 Bent?



## flandjm (Dec 28, 2006)

I thought that I read somewhere that Compact Fluorescents were the same bulb as T5s, just bent to fit in a tighter space. CF are less efficient than T5 because of the restrike caused by the u shap. 

Am I mistaken?

Do you know where I can find more info on this? I tried google and searching this website with no real help. Thank You!

Jennie


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## BryceM (Nov 6, 2005)

That assumption is correct. CF's are a bit less efficient than T-5's becasue they're bent, but the actual difference in efficiency isn't that big of a deal.

If you're looking for more info, do a search at the "other" forum (Planted Tank) and look for posts by Rex Grigg. He's posted quite a bit about them.


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## flandjm (Dec 28, 2006)

*Thank You!*

I find just when I think I start to think I know what I am talking about, someone (or something) rocks the boat.


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## hoppycalif (Apr 7, 2005)

flandjm said:


> I find just when I think I start to think I know what I am talking about, someone (or something) rocks the boat.


Welcome to the club! We have many members in that club, sharing that same experience.


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## ruki (Jul 4, 2006)

flandjm said:


> I thought that I read somewhere that Compact Fluorescents were the same bulb as T5s, just bent to fit in a tighter space. CF are less efficient than T5 because of the restrike caused by the u shap.
> 
> Am I mistaken?


There is a bit more to it than that.

Compact fluorescent and T5s seem to be approximately the same diameter, but after that there are some significant differences.

CF are over-driven as compared to normal ouput T5 tubes. It's more like T5 HO. Normal Output T5 tubes emit up to 104 lumens per watt. The Hight Output version of T5 tubes produces up to 92 lumens per watt. CF produces 50-70 lumens per watt. I think it's more than just re-strike; T5s were designed to be energy efficient while CF was designed to be space efficient.

With T5, you know more of what you are getting. The shape, the pins and the ballast are all standard. With CF you get multiple shapes, pin connections and some have ballast limitations. It's more difficult to get information on exactly what your CF fixture and bulb are. Sometimes it's difficult to get even basic lumen information. 

Because T5 is a European standard and its tubes are expensive, it's also useful to compare CF with T8s. T8 bulbs produce 60 to 93 lumens per watt.



> Do you know where I can find more info on this? I tried google and searching this website with no real help. Thank You!
> Jennie


Some links on this:
Commercial Lighting Tax Deduction
Luminous efficacy - Wikipedia, the free encyclopedia
ENERGY STAR


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## gf225 (Mar 26, 2005)

Great post Ruki! Thanks.


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## flandjm (Dec 28, 2006)

Thanks ruki for explaining it to me twice!


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