Green Home with Dimmable Fluorescents

Dimmable CFLs are available for both integral and modular designs. Most useelectronic, rapid start ballasts. Dimming can be achieved gradually, without flicker,and without changes in color temperature. Some types of ballasts and controlsutilize low voltage wiring to regulate the dimming and some simply reduce the power to the ballast. It is important that the lamp and dimming system be compatible.

Dimmable CFLs can be used in new construction or to retrofit existingincandescent fixtures in office buildings, residential and institutional living facilities,and any other place where incandescent fixtures have been used in the past. Mostdramatic savings will be in applications with high annual operating hours. Comparedto incandescent lamps, CFLs reduce the heat load (a benefit in summertime and a detrimentin the heating season); thus, maximum benefit would result from installation in a climate with a long cooling season.

Dimmable versions of compact fluorescent lamps (CFLs) allow adjustment of lighting levels to meet user requirements and increase occupant comfort. CFLs produce about 4 times as much light as an incandescent lamp of the same wattage and can last ten times longer. Dimmable CFLs can save additional energy. The use of dimmable CFLs is increasing due to improved product availability and reliability. The color rendition of many models is similar to an incandescent lamp.

Performance/Costs: CFLs produce approximately four times more light output per watt than incandescent lamps. This means a 100- watt incandescent lamp can be replaced with about 25 watts of CFL. Simple paybacks are usually less than 3 years with lamps that operate more than 4,000 hours per year. Many CFLs have an expected operating life of 10,000 hours, which is 5 to 13 times longer than incandescent lamps. This can save a great deal on the maintenance labor for lamp replacement. Dimming increases savings even further. As with many energy efficiency measures, the exact reduction in energy use due to dimming varies widely with application and operation. However, a 30% reduction is reasonable to expect if building occupants receive some awareness training and encouragement to take advantage of the technology.

With proper controls, CFLs can be dimmed from 100% down to 10% light output. Dimming controls cost about $100 to $125 for a wall-mounted solid-state dimmer that can control up to a 20-amp circuit; for retrofit applications, a third control wire must be installed. A conventional dimmer designed for incandescent lighting may cost only $10 or less. However, as described under “Applications” above, such dimmers are generally not recommended. Solid state ballasts are also slightly more energy efficient.