Energy-efficient design alternatives to residential recessed downlights

Peter Banwell, US Environmental Protection Agency, USA
Mariana Figueiro, Rensselaer Polytechnic Institute, USA

Keywords

energy-efficiency, recessed downlights, lighting quality, residential lighting, energy star, carbon emissions, energy-efficient lighting design, compact fluorescent lamps

Abstract

Electric generation capacity shortages, resulting in blackouts, have affected millions of Americans since 1999. With shortages most critical in California, policy makers and utility planners are scrambling for options to alleviate the problem by bringing electricity supply and demand into balance. Further, ongoing efforts by electric utilities are pumping over $30 million annually into the promotion and purchase of energy-efficient lighting.

In addition to electricity shortages, countries are designing programs to reduce Carbon Dioxide and other greenhouse gasses, in an international effort to reduce the threat of climate change. Electric utility promotion of efficient lighting, the electricity shortages, and the threat of climate change highlight the need for the research community to uncover all viable opportunities for energy-efficient lighting applications.

The residential sector accounts for 35 % of total energy use in the United States (US) with lighting accounting for 10 to 15 % within that sector. This paper focuses on residential lighting, and the potential for substituting standard incandescent lighting for well-designed, energy-efficient lighting in residential new construction.

In this paper, the authors argue that there are alternatives to the present standard lighting packages used in new homes. First, the authors conducted field research by documenting floor plans and lighting layouts used in typical new homes.

A lighting designer then took existing floor plans and lighting layouts and presented two alternative lighting designs. Those lighting designs substituted efficient luminaires for traditional, inefficient, incandescent luminaires. The design objectives were to provide equal or better lighting, with substantially reduced energy use profiles, using luminaires that are readily available rather than prototype models. Light levels were simulated using Lumen Micro software, while energy and financial data were evaluated using HomeCalc software.

The results of this study show that the use of efficient lighting is both an aesthetically and financially superior choice for US homeowners when compared with standard incandescent luminaires. Both alternative designs were shown to provide more light with lower homeowner maintenance and substantially lower operating costs. Our economic analysis fully supports the choice of efficient lighting systems and alternative energy-efficient lighting designs for residential new construction.

This study is the first of its kind both in the approach, the data analysis, and the conclusiveness of the findings.

The results presented here could provide the analytical basis for program design of residential new construction lighting programs. Given the potential size of the residential market, and the fact that most lighting is inefficient, adoption of these energy efficiency methods would yield substantial national energy savings.