Technologies >
ENERGY-SAVING T8 AND SUPER T8 LAMPS
Description: Next-generation T8 lamp technology has resulted in a number of 4-ft. choices that can be used to save energy. Energy-saving lamps include 25W, 28W and 30W T8 lamps, and Super T8 lamps offer higher light output, which can be used to reduce lamp and/or fixture count or operate with low-output electronic ballasts.
30W T8 Lamps: If instant start operation is acceptable, a 30W T8 system can be used to generate additional energy savings. Since there is a high population of instant start ballasts already in the field, switching to this energy-saving lamp can be a simple proposition.
28W T8 Lamps: A 28W T8 lamp is available for instant start and programmed start; when operated with a reduced-power (low light output) ballast, power consumption is 24 percent lower than a standard reduced-power instant start system with a six percent reduction in light output.
25W T8 Lamps: If instant start operation is acceptable, a 25W T8 system with a compatible electronic ballast can be installed.
Super T8 Lamps: Super T8 lamps are 32W T8 lamps but with a barrier-coat design, high lumen maintenance (88-92 percent end-of-life lumens), long service life and high light output—3100+ initial lumens as opposed to 2850 for a typical standard T8.
Table 1. Comparison of standard T8 and Super T8 systems. Source: Walerczyk, S. and B. Liebel, 2002: “Cutting-Edge Retrofitting and Relighting.” Seminar presentation at Lightfair International 2002, June 2, San Francisco, CA.
Lamp/Ballast |
Initial Lumens |
Ballast Factor |
Lamp Life (hours) |
System Wattage |
Standard F32T8 w/electronic ballast |
2,850 |
0.88 |
20,000 |
1-lamp fixture 30W
2-lamp fixture 58W
3-lamp fixture 87W
4-lamp fixture 114W |
Super F32T8 w/reduced-power electronic ballast |
3,200 |
0.78 |
24,000 |
1-lamp fixture 25W
2-lamp fixture 48W
3-lamp fixture 73W
4-lamp fixture 96W |
Ballasts: For energy-saving T8 lamps, energy savings can be optimized by combining the lamp with a high-efficiency ballast or, if lower light output is acceptable, a low-output ballast. For higher light output, a high-output ballast can be installed. For Super T8 lamps, energy savings can be optimized by combining the lamp with a high-efficiency ballast, a standard ballast (and then delamping or reducing the number of fixtures), or a low-output ballast (which can produce comparable light output for 15-20 percent less wattage than standard T8 systems).
Table 2. Upgrade opportunities: System performance/savings on new T8 options vs. 4-lamp 277V T12 system. Source: Advance.
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T12 |
Savings vs. T12 |
Net System Lumens/Watt* |
(4) 34W T12 |
(2) Energy-saving magnetic |
144 |
.88 |
100% |
N/A |
56.2 |
Need more light output? Here are several options:
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T12 |
Savings vs. T12 |
Net System Lumens/Watt* |
(4) 30W T8 |
(1) High-efficiency electronic |
100 |
.87 |
118% |
31% |
95.7 |
(4) 32W T8 |
(1) Standard electronic |
112 |
.88 |
117% |
22% |
84.9 |
(4) 32W T8 |
(1) High-efficiency electronic |
106 |
.87 |
116% |
26% |
88.6 |
(4) 28W T8 |
(1) High-efficiency electronic |
93 |
.87 |
111% |
35% |
96.5 |
Need roughly the same light output? Here are several options:
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T12 |
Savings vs. T12 |
Net System Lumens/Watt* |
(4) 30W T8 |
(1) High-efficiency low-wattage (LW) electronic |
89 |
.77 |
105% |
38% |
95.2 |
(4) 32W T8 |
(1) High-efficiency LW electronic |
95 |
.77 |
103% |
34% |
87.5 |
(4) 25W T8 |
(1) High-efficiency electronic |
83 |
.87 |
98% |
42% |
95.6 |
(4) 28W T8 |
(1) High-efficiency LW electronic |
82 |
.77 |
98% |
43% |
96.9 |
Willing to sacrifice some light output to maximize energy savings? Here are several options:
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T12 |
Savings vs. T12 |
Net System Lumens/Watt* |
(4) 25 W T8 |
(1) High-efficiency LW electronic |
75 |
.77 |
87% |
48% |
93.6 |
* Net system lumens per watt = (mean lumens X number of lamps X ballast factor) / input watts
Table 2. Upgrade opportunities: System performance/savings on new T8 options vs. standard 4-lamp 277V T8 system. Source: Advance.
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T8 |
Savings vs. Standard T8 |
Net System Lumens/Watt* |
(4) 32 W T8 |
(1) Standard electronic |
112 |
.88 |
100% |
N/A |
84.9 |
Need roughly the same light output? Here are several options:
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T8 |
Savings vs. Standard T8 |
Net System Lumens/Watt* |
(4) 30 W T8 |
(1) High-efficiency electronic |
100 |
.87 |
101% |
11% |
95.7 |
(4) 32 W T8 |
(1) High-efficiency electronic |
106 |
.87 |
99% |
5% |
88.6 |
Willing to sacrifice some light output to drive additional energy savings? Here are several options:
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T8 |
Savings vs. Standard T8 |
Net System Lumens per Watt* |
(4) 28 W T8 |
(1) High-efficiency electronic |
93 |
.87 |
94% |
17% |
96.5 |
(4) 30 W T8 |
(1) High-efficiency. LW elec. |
89 |
.77 |
89% |
21% |
95.2 |
(4) 32 W T8 |
(1) High-efficiency LW elec. |
95 |
.77 |
88% |
15% |
87.5 |
Willing to sacrifice even more light output to maximize energy savings? Here are several options:
System
Lamps |
System
Ballasts |
Input Watts |
Ballast factor |
Light Output vs. T8 |
Savings vs. Standard T8 |
Net System Lumens per Watt* |
(4) 28 W T8 |
(1) High-efficiency LW elec. |
82 |
.77 |
84% |
27% |
96.9 |
(4) 25 W T8 |
(1) High-efficiency electronic |
83 |
.87 |
83% |
26% |
95.6 |
(4) 25 W T8 |
(1) High-efficiency LW elec. |
75 |
.77 |
74% |
33% |
93.6 |
* Net system lumens per watt = (mean lumens X number of lamps X ballast factor) / input watts
See also:
High-Efficiency Electronic Ballasts
Upgrading T8 Systems
