| OFFICE INTERIOR: New Installation Comparison |
3-lamp T8 parabolic fixtures |
2-lamp T5 fixtures |
| LAYOUT |
Fixture Mounting Height |
10 ft. |
10 ft. |
| LAMP & FIXTURE DATA |
Initial lamp lumens |
2800 |
2800 |
| Number of lamps |
3 |
2 |
| Initial fixture lumens |
8400 |
5600 |
| Ballast factor |
0.90 |
1.15 |
| Initial fixture lumens (ballast corrected) |
7560 |
6440 |
| Lamp lumen depreciation |
0.90 |
0.95 |
| Luminaire dirt depreciation |
0.88 |
0.88 |
| Fixture efficiency (%) |
69.4 |
88.9 |
| Maintained fixture lumens |
4722 |
5439 |
| Fixture watts |
87 |
66 |
| Fixture lumens/watt |
54 |
82 |
| FOOTCANDLES |
CRI |
72 |
82 |
| FC Average Maintained |
41 |
40 |
| OPERATING DATA |
Number of fixtures |
228 |
198 |
| Cost/kWh |
$0.085 |
$0.085 |
| Total wattage |
19836 |
13068 |
| Square footage |
24000 |
24000 |
| Total installed price |
$18,012 |
$29,700 |
| Watts/square foot |
0.83 |
0.54 |
| Annual operating hours |
4380 |
4380 |
| SAVINGS ANALYSIS |
Annual Energy Costs |
$7,385 |
$4,865 |
| Annual Energy Savings |
n/a |
$2,520 |
| COMMERCIAL BUILDINGS DEDUCTION |
Lighted area (square feet) |
24000 |
24000 |
| ASHRAE/IES Standard 90.1-2001 requirement (watts/square foot) |
1.3 |
1.3 |
| LPD below Standard 90.1-2001 |
36% |
59% |
| Eligible deduction per square foot |
$0.52 |
$0.60 |
| Max. Commercial Buildings Deduction (final benefit depends on owner’s tax rate) |
$12,480 |
$14,400 |
| CONTROLS |
Mandatory controls (see Standard 90.1-2001) and bi-level switching (required in all office occupancies except store rooms, lobbies and restrooms) can increase energy savings. |
