Oikos: ESB: Energy-Efficient Lighting Patterns

Energy Source Builder

Lighting Patterns Prove to be Efficient, Affordable and Popular

Conventional

Energy-Efficient

Kitchen Lighting

indirect linear fluorescent lights above the cabinets
recessed halogen downlights above the counter
fluorescent task lights under the cabinets

If you want to impress potential home buyers, think lighting. It may be one of the best ways to distinguish yourself from the competition. In most houses, especially specs, the lights are simply installed. In many cases, the electrician decides on the placement of fixtures and the types of controls. A better approach is to design the lighting. Although it's best to hire a lighting designer, few residential projects benefit from the professional touch. That's one reason that Lighting Research Center (LRC) developed The Lighting Pattern Book for Homes. The book identifies 147 patterns that builders and homeowners can follow to improve the quality of residential lighting--and energy efficiency.

A unique demonstration of the usefulness of these patterns occurred in 1994 during a showcase of homes in Rochester, New York. Some of the patterns were used in a side-by-side demonstration that showed how proper design can be more appealing to the market while also being more energy efficient. Two nearly identical townhouses were used for the demonstration. These typical two-bedroom townhouses were targeted for middle-income buyers with prices starting at $119,000. One townhouse received the conventional builder's package, along with decorative lamps selected by an interior decorator. In the second townhouse, Rita Koltai (then a graduate student at the LRC) applied seven patterns from the Lighting Pattern Book. Then, she compared the two townhouses for light level, consumer acceptance, savings and cost.

Light Levels

Light levels were measured in 35 locations in each townhouse. Overall the energy-efficient townhouse had better light levels than the conventional side. In the conventional townhouse, 71 percent of those locations met or exceeded the light level recommended by the Illumination Engineers Society (IES). On the energy-efficient side, 89 percent of the measurement points met IES recommendations.

Consumer Acceptance

During the two-week home tour, 706 visitors to the townhouses completed a survey. Seventy-eight percent said they liked the energy-efficient lighting as well as or better than the conventional lighting. Ninety-seven percent said they would pay more for energy-efficient lighting, and half said they would spend an additional $825 or more.

Builders and home designers generally believe that consumers don't like fluorescent lights, but that may be changing. Before entering either townhouse, 95 percent of the respondents agreed that "fluorescent and low-wattage halogen bulbs can be used successfully to create an attractive appearance."

Tips for Lighting that's Attractive and Energy Efficient

Use fluorescent lamps with a high color rendering index (CRI).
Direct light at walls to increase the feeling of spaciousness.
Use quiet electronic ballasts with all fluorescent lamps.
Install halogen lamps that provide equal light, but with lower wattage than typical incandescents.
Offer dimming controls and multiple switching options.
Use motion detector switches that turn on manually, but turn off automatically.

Savings

Occupants of the energy-efficient townhouse would save money by using less energy and by purchasing fewer replacement lights. Most of the more efficient lights were fluorescent. Compact fluorescent lamps can burn 10 times longer than conventional incandescents. Linear fluorescents can burn an average of 20 times longer.

By using more efficient lights, fixtures and controls, Koltai estimated the occupants would save $183 per year. This includes $172 in energy savings and $11 in reduced lamp replacements. The savings were calculated using an electric rate of 10¢/kWh.

Cost

Minimizing both initial costs and operating costs was an important goal of the project. Total equipment cost for the conventional townhouse was $1954. Lighting equipment for the energy-efficient townhouse was donated. Researchers estimated the cost of energy-efficient equipment was equivalent in grade to those used in the conventional house at $1965. Although equipment costs were essentially the same, the efficient fixtures often required additional labor to install. For example, carpenters built valances in the living room and bedrooms on site. The additional installation costs came to $1307.

There are two ways to judge whether the investment made for efficient lighting is worthwhile. The first is simple payback. It would take seven years for the annual savings of $183 to cover the $1307 cost. Cash flow is another way to evaluate the investment. Adding the initial investment to a 25-year, 8-percent mortgage would add about $120 to the annual payment. The annual savings exceed this additional payment by $63, leaving a positive cash flow from the first year.

This unique side-by-side research shows that energy-efficient lighting not only saves money, it can be attractive to home buyers. The key is good design. Even if you can't hire a professional lighting designer for every job, you can apply basic lighting patterns.

Conventional