ENERGY ADVISOR

About the Lighting Module

The calculation of annual energy consumption by lighting utilizes the following equation:

Annual consumption = Lamp Wattage * Hrs/day of usage * 365 days / yr.

For the quick consumption of lighting energy use, metered lighting data from the Tacoma Public Utility report was used. This report provides average lamp power (watts) and average usage by room. Users of the module are asked for the total number of lamps in each of a series of rooms. For each room the number of lamps is multiplied by the average wattage and hours of use (Table 1) to arrive at a typical energy consumption for that room. Obviously, house with non-typical usage, for example a light that is constantly on, or situations where the homeowner has already upgraded to efficient lighting technology will not be accurately modeled using the method described above. For these situations, we developed the detailed lighting module. The detailed module allows users to enter wattage and hours of use for every fixture in the house, thus providing a fully-customized calculation.

Maggie Pinckard
Research Associate, LBNL

References

Table 1: Lighting Energy Consumption from TPU Survey
Fixture Location Average Lamp Wattage Average Watts / Fixture Average Unit Energy Consumption (UEC) Average Usage Annual Lamp UEC Annual Fixture UEC
(Watts) (Watts) (kWh/period) (hrs/day) (kWh/yr) (kWh/yr)
Other 71.79 102.76 23.51 1.47 39 55
Bedroom 68.32 94.11 13.64 1.06 26 36
Closet 60.04 65.68 13.22 1.28 28 31
Dining 62.47 165.03 50.2 2.25 51 136
Hall 65.02 78.05 17.5 1.72 41 49
Family_Room 73.42 106.22 33.68 1.99 53 77
Garage 75.09 102.88 21.56 1.89 52 71
Kitchen 59.17 95.13 48.82 3.15 68 109
Living_Room 98.24 123.61 41.34 2.41 86 109
Master_Bedroom 67.83 92.73 17.57 1.2 30 41
Outdoor 83.63 110.02 33.61 2.88 88 116
Utility_Room 61.61 83.57 27.46 2.42 54 74
Bath 70.47 138.29 36.22 1.91 49 96
ALL 72.14 105.09 30.15 2.03 53 78
Whole-House 1871 1947

Source: LBNL analysis of TPU survey data.

References:
Jennings, J., M. Moezzi, R. Brown, E. Mills, R. Sardinsky, B. Heckendorn, D. Lerman, L. Tribwell. 1997. "Residential Lighting: The Data to Date." Journal of the Illuminating Engineering Society. Vol. 26, No. 2. Summer 1997. also LBL-35484, March, 1996.

Also:
Tribwell, Lyle S. and David I. Lerman. 1996. "Baseline Residential Lighting Energy Use Study." Proceedings of the 1996 ACEEE Summer Study on Energy Efficiency in Buildings. p. 3.153.