Energy-Efficient Incandescent Lighting
Although incandescent lamps use more energy than other types of lamps to produce the same amount of light, there are some situations where they are appropriate.
They have the sparkle and definition of sunlight, and they are best suited for frequent on-off situations. Here are a few ways to reduce energy costs with incandescent lamps.
Lower Wattage Incandescent Lamps
In general lighting situations, lower-wattage incandescent lamps can be used to yield substantial energy savings without significantly affecting lighting levels. For example, a 67-watt replacement for a 75-watt lamp produces only 5% less light, yet uses 11% less electricity.
130 Volt Incandescent Lamps
For hard-to-reach places where changing the lamp can be difficult, 130-volt incandescent lamps can be an option . Designed to operate in 130-volt circuits, when used in 120-V service they can last twice their expected life while providing about 95% of their normal light output.
 A-shaped Incandescent Lamp |
The incandescent lamp consists of a wire filament mounted inside a glass bulb containing a gas or vacuum. When the lamp is connected to an electrical circuit, the current passing through the wire must overcome the filament's resistance, and the power consumed heats the filament to become incandescent ("glowing with heat"). |
Ellipsoidal Reflector Lamps
An ellipsoidal reflector (ER) lamp can be a wise replacement choice for a reflector floodlamp in a deeply recessed ceiling downlight fixture ("potlight") where 50% or more of the light can be trapped inside the fixture. The ER lamp is designed to project more light out of the fixture than the floodlamp while using less power. For example, a 75-watt ER replacing a 150-watt regular floodlamp often yields more light, and yet uses only half the power. Energy savings can be substantial! If you need more light, try a larger ER lamp, or a socket extension that brings the front surface of the lamp closer to the opening of the fixture.
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| Floodlight – Reflecting surface sends light forward in a relatively wide beam pattern. | ER Lamp – Ellipsoidal reflector sends light forward to converge in front of the lamp. |
Replacing Two For One
In many cases you can use a single, more powerful lamp where you now have two or more. The larger the lamp, the more efficient it is; higher wattage = more lumens of light produced per watt. (This is true for all except fluorescent lamps.) For example, two 60-watt incandescents (1,680 lumens) can be replaced with one 100-watt lamp (1,800 lumens) that yields more light and saves 20 watts of electricity. A 20-watt reduction can save 15 kWh of electricity over the lamp's life – enough to justify replacing old lamps before they burn out.
