PC vs. t12 vs. t8 vs. t5

[crossxfire2]

Alright, more light is emitted from the smaller tubes, right? PC is brighter than t8, but t5 is brighter than PC? But, T8 is brighter than T12? This doesn't really concern corals. It is more for African Violets.... but anyway, is this information correct? My main concern is between the t12 and t8.... how big is the brightness gap? I saw them right next to each other at home depot, and the t8 was brighter.... but I don't know how much of a brightness gap is between them.

[caferacermike]

Unless you run your T-12 as VHO, between 80-100w. And it's not really so much that one bulb is brighter but that you can fit MORE of them in one area.

[crossxfire2]

how would you run a t-12 as VHO?

[alton]

Go to gelighting.com and check out the lumens chart for t5 / t8 / t12

[cpreefguy]

Also, it is not necessarily the bulb that will determine how "bright' each one is. The reflectors will have a lot to do with it

[brewercm]

I always thought that all VHO bulbs were T12? Not necessarily the other way around though.

[crossxfire2]

Well in that case, what is better about t-5 than pc I ask? Just...better spectrum options??? Haha I am such a lighting newbie.

[sharkboy]

Read this link for a lot of info..it is lengthy but very informative.
http://reefkeeping.com/issues/2007-12/newbie/index.php

[alton]

I received the following information from GE Lighting comparing T5 to T8 (At the bottom is a graph that shows a simple comparison)

T8 versus T5, Which is the better lamp?


There is some debate as to which is the better lamp to be using on new designs. Fixture manufacturers state the fixture efficiency can be improved with smaller diameter lamps, but the difference is only 3/8 of an inch as far as diameter. A well-designed T8 fixture can be just as efficient. So lets look at some of the variable between the two lamp types.



The standard F32T8 system efficiency is around 81 lumens per watt. The standard F54T5HO is around 80. Using a High Efficiency Ballast and either F28T8 or F32T8HL lamps have efficiency above 94%. See attached excel spreadsheet.



The F54T5HO uses Program Start ballast, which is a good choice for switching more than twice a day. The F32T8 can use Program Start ballast or Instant Start ballast. If the application is continuous or only turns on and off less than 5 times a day, the Instant Start ballast is a good choice. Instant Start ballast is less cost.



The F54T5HO can be used in a lot of applications: High Bay, Indirect, Cove lighting, etc. It should not be used in direct light applications at lower mounting heights below 9 foot because of the glare. The F32T8 can be used in all applications.



Both lamps can be dimmed. There is a limited number of dimming ballast manufacturers for T5. There are a lot of T8 dimming ballast manufacturers. The Philips T5 lamps cannot be dimmed. No present restriction on T8, except that it must be the full wattage versions, not the

30w WattMiser or F28T8.



The typical high bay is a four-lamp T5 or a six-lamp T8. Either one of these fixtures come in a wide arrangement of sizes and styles. The light output is very close to each other. The F54T5 operates at 234 watts. The F32T8 operates at 5 to 15% less energy depending on the lamp used.



Some F54T5HO four-lamp ballasts in the market are series / parallel wired. If one lamp goes out, one other lamp goes out. The GE ballast for T5 and T8 are full parallel wiring. If one lamp goes out, all the others stay on.



The High bay GE 454 T5HO ballast has bi-level capability in single ballast. It can be switched from 4 lamps down to 2 lamps for 50% energy savings in unoccupied areas. The High bay GE Ultra fixture uses two H ballast. It can be switched from 6 lamps down to 2 lamps providing 66% energy savings.



The cost of single T5 ballast is roughly the same cost as two Ultra T8 ballast.



The cost of a single T5 lamp is roughly the same cost as two T8 lamps.



At twelve hours per start, the GE F54T5HO is 36,000 hours. The GE F28T8 is 24,000 hours. The GE F32T8HL is 29,000 hours.



The Ballast Factor for the F54T5HO ballast is a 1.0. The Ballast Factor for the F32T8 can be 0.6, 0.77, 0.87, or 1.15 depending on the application. Using various ballast factors for light level variance can standardize a single T8 lamp.



The cathodes of the F54T5HO are different at each end. The cathode at the monogram end is longer than the other end. The cathode at the monogram end is the cold spot. For vertical installations, this is important. Placing the monogram end up in cold temperature applications will heat up this cold spot more and thus provide more light. Placing the monogram down in hot applications will keep the lamp cooler.

# Ballast Lamp Watts Lumens Maint Mean Lm BF System Lm L% to Baseline LPW
2 446-L-SLH-TC-P F34/CW/RS/WM 74 2,650 86% 2,279 0.9 4,102 100% 55.4 Baseline
2 B254PUNV-D F54W/T5/HE/841 117 5,000 94% 4,700 1 9,400 229% 80.3
2 B232I120RH F32T8/SP41 58 2,850 94% 2,679 0.88 4,715 115% 81.3
2 B228PUNV-C F28W/T5/HE/841 64 2,900 94% 2,726 1 5,452 133% 85.2
2 GE -232-MAX-N F30T8/SP41 54 2,800 94% 2,632 0.88 4,632 113% 85.8
2 GE -232-MAX-N F28T8/SP41 48 2,750 94% 2,585 0.88 4,550 111% 94.8