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Light Bulb Comparison

This article compares manufacture provided specifications for power (measured in Watts) and light (measured as Lumen) for several popular lamp types.

Other important factors such as reflectors, Kelvin color (spectrum), ballast/power factor, lifetime, and form factor are not addressed.

The use of Lumen is hotly debated due to differences in human-centric perspective and the photosynthetically active radiation PAR of Chlorophyll. Spectrum comparison of Sylvania T12 , T8, and T5 support the approximation that total intensity scales with lumens for freshwater planted tanks. For salt water reefs factors such as unshaded tropical sun filtered through a water column makes the discussion in terms of Lumens unsatisfactory. Then again, adding nitrates to a reef makes no sense either.

A fuller treatment of this topic can be found here:

Comparison of Popular Bulb Types
Bulb Type# Lumens over Watts (initial, mean)* Efficiency lm/W** Multiplier T12***
Incandescent (~3500K) 1210/75 21.0-(16.1)-7.4 0.22
T-12 Normal Output (NO) (4100K)
High Output (HO)
Very High Output (VHO)
(3200, 2880)/40
(4050, 3281)/60
(6600, 4620)/115
T-8 Normal Output (NO) (4100K) (2800, 2520)/32 78.8 1.35
T-5 Normal Output (NO) (4100K, 35C)
High Output (HO) (4100K, 35C)
(2900, 2755)/28
(5000, 4750)/54
Spiral Compact 1250/20 62.5 0.86
Power Compact (4800,4128)/55 75.0 1.04
Metal Halide+
High Pressure Sodium+
LED (prototype, commercial) 80,~32 0.44

# Quote: unless noted
* fluorescent bulbs = 4',
** (high, - (quoted) - low), lm/W from mean value
*** multiplier of intensity to compare T12. i.e. 28W T5 = 1.37 W T-12. Example 2 WPG T5 = 2.74 WPG T12.

Incandescent bulbs

o Operation described here:
o "Aquarium" 15 W bulb ~7.4 lm/W.
o Color ~2850K

Linear fluorescent lamps

o Operation described here:
o Bulb diameter: T-12 -> 12 one-eighths or 1.5". (T8 = 1")
o Medium bipin contacts used for T12 NO, T10, T8 and T6 in standard lengths.
o From ~3000K to 6700K

High Output

o T12 High Output variants: The HO and VHO T12 lamp use recessed double contact to prevent interchange and operate by increasing the current (T12 NO = 430 mA, HO = 800 mA, VHO = 1500 mA)
o T5 High Output variants: The T5 and T5 HO use the same miniature bipin contact but require a load sensing ballast.


o Ballast power factor is the ratio of the lamp design current over the supplied ballast current.
o For example a energy saving T12 ballasts can have 0.88 power factor resulting in 2775 lumens X 0.88 = 2376.
o Fluorescent lamps can be "overdriven" with a high power factor ballast, or creative wiring. Over-Driven Normal Output ODNO is covered in depth here: ODNO
o Rule of thumb is 2X = 50%, 3X = 75% lm, 4X = 100% increase.
o The member "Shalu" notes that some combinations actually become more efficient when OD. Suggested that 2x OD 18" T8 outputs 2.5x light!

Other lamps:

o Spiral Compact as screw in type. Total lm quoted, expect significant loss to restrike.
o Reports that power compact (PC) are bent T5 with 55/66W power dependent on ballast, not bulb.
o HID operation:


o Link to WPG:
o Eric Olsen's comparison:
o Energy/area method:
o DIY (do it yourself) projects have an inherent risk above standard operation. Any DIY ideas mentioned here are for completeness only and does not constitute and endorsement. Water and electricity do not mix!

o "BlueRam"
o "Shalu"

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