Results From A Comprehensive Residential Lighting Retrofit. 09-96

Secondary Author(s)

Schrum, Lynn

Report Number





Buildings; Energy Consumption; Energy Efficiency


A single family residence in Miami, Florida was used as a case study to determine how residential lighting energy use could be reduced by substituting energy efficient lamps and fixtures. The three person household was chosen based both on its high utility bills and extensive use of interior lighting. A detailed audit revealed 40 lamps or bulbs on 26 controls (switches) with a total connected load of 2.5 kW. All major energy using appliances in the home were sub-metered so that lighting and other plug loads could be differenced from the measured total power demand. Also, each of the individual lighting fixtures were metered using time of use light loggers in the fall of 1995 so that the run time each was used could be determined. The total household lighting use, estimated by the light loggers was 4,050 kWh/year or about 23% of annual total consumption. The metering revealed that outdoor lighting fixtures used the most electricity, followed by lighting in the kitchen, garage and study. Fixtures in these areas accounted for 80% of total lighting energy use. The house was monitored from May through mid December, 1995 in a baseline condition. On December 11th, 27 various compact fluorescent lamps (CFLs) and other more efficient lighting sources were substituted for the majority of incandescent A-lamps in use. Motion sensor controls were provided for the exterior lighting. The connected lighting load was dropped to 1.1 kW. The total hardware cost for the retrofit was approximately $400. The building was monitored in its altered condition through June of 1996 with the metered lighting and plug loads differenced with those during the pre-retrofit period. The measured savings was approximately 6.8 kWh/day -- equal to a reduction in household lighting energy consumption of some 61%. Figure E-1 shows the metered before and after lighting and plug load energy profiles along with the estimated savings. The lighting energy use reduction is highest between 6 and 10 PM. A more conservative savings estimate, (obtained by multiplying the per fixture light logger run hours by the changed lamp wattage), calculated a savings of 5.2 kWh/day (47%) although no estimates were available for the savings of the outdoor lighting system alterations due to difficulties with the exterior light loggers in the post period.

Date Published



Buildings - Energy Consumption; Buildings - Energy Efficiency

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