Energy Efficient Lighting

Energy Efficient Lighting

If every American home replaced just one light bulb with an ENERGY STAR qualified bulb, we would save enough energy to light more than 3 million homes for a year, more than $600 million in annual energy costs, and prevent greenhouse gases equivalent to the emissions of more than 800,000 cars.

ENERGY STAR qualified CFLs

  • ENERGY STAR qualified bulbs use about 75 percent less energy than standard incandescent bulbs and last up to 10 times longer.
  • Save about $30 or more in electricity costs over each bulb’s lifetime.
  • Produce about 75 percent less heat, so they’re safer to operate and can cut energy costs associated with home cooling.
  • Are available in different sizes and shapes to fit in almost any fixture, for indoors and outdoors.


Artificial lighting consumes almost 15% of a household’s electricity use. Use of new lighting technologies can reduce lighting energy use in homes by 50%–75%.

You can reduce lighting energy use by selecting lighting and sources that use energy more efficiently, and by installing lighting controls.

Fluorescent Lighting

Illustration of six types of compact fluorescent lamps.Fluorescent lamps use 25%–35% of the energy used by incandescent lamps to provide the same amount of illumination (efficacy of 30–110 lumens per watt). They also last about 10 times longer (7,000–24,000 hours).

DOE CFLs can replace incandescents that are roughly 3–4 times their wattage, saving up to 75% of the initial lighting energy. Although CFLs cost 3–10 times more than comparable incandescent bulbs, they last 6–15 times as long (6,000–15,000 hours).

Compact fluorescent lamps (CFLs) come in a variety of sizes and shapes including (a) twin-tube integral, (b and c) triple-tube integral, (d) integral model with casing that reduces glare, (e) modular circline and ballast, and (f) modular quad-tube and ballast. CFLs can be installed in regular incandescent fixtures, and they consume less than one-third as much electricity as incandescent lamps do.

LED Lighting

LEDs (Light Emitting Diodes) are small, solid light bulbs which are extremely energy-efficient. Until recently, LEDs were limited to single-bulb use in applications such as instrument panels, electronics, pen lights and, more recently, strings of indoor and outdoor Christmas lights.

Recent improvements in manufacture have lowered the cost of LEDs, which has expanded their application. The bulbs are now available in clusters, from 2 to 36 bulbs, and are popular especially for battery powered items such as flashlights and headlamps. LEDs are also available in arrays which fit standard AC and DC receptacles, lamps, recessed and track lights.


  • Long-lasting – LED bulbs last 10 times as long as compact fluorescents, and 133 times longer than typical incandescents.
  • Durable – Since LEDs do not have a filament, they are not damaged under circumstances when a regular incandescent bulb would be broken. Because they are solid, LED bulbs hold up well to jarring and bumping.
  • Cool – these bulbs do not cause heat build-up; LEDs produce 3.4 btu’s/hour, compared to 85 for incandescent bulbs.
  • Energy-saving – LEDs use a fraction of the wattage of incandescent bulbs. Batteries will last 10 to 15 times longer than with incandescent bulbs. Also, because these bulbs last for years, energy is saved in maintenance and replacement costs. Many cities in the US are replacing their incandescent traffic lights with LED arrays because the electricity costs can be reduced by 80% or more.
  • Light for remote areas – because of the low power requirement for LEDs, using solar panels becomes more practical and less expensive than running an electric line or using a generator for lighting.


  • Cost  although the cost keeps going down, LEDs are still expensive. A single AC bulb (30 LED), replacing a 25 watt incandescent, may cost about $40.
  • Light Field – LEDs are focused lights, and therefore are best as task specific lighting such as reading lights, desk lamps, night lights, spotlights, security lights, signage lighting, etc. They do not radiate light in 360 degrees as an incandescent does. The light will be bright where you point it towards.

    New designs in LED bulbs are addressing this problem of directional focus. Diffuser lenses with clustered bulbs are becoming more common on the market which is broadening the applications for LED use in the home.

Although LEDs are expensive, the cost is recouped over time and in battery savings. For the AC bulbs and large cluster arrays, the best value comes from commercial use where maintenance and replacement costs are expensive. Traffic lights, for example, are being switched over to LEDs in many cities.

Smaller arrays, such as those in flashlights, headlamps and small task lights are great for specialty and outdoor use. New clustered arrays with various lenses are now available for more residential applications.


Industrial lighting (fluorescent tubes)

Lamps come in hundreds of different lengths and widths, but the most energy-efficient lamp is a T-8, which is a one-inch diameter tubular lamp. When compared to the past U-M standard T-12 lamps, the new standard T-8s use less energy and have the same lamp life. T-8 lamps are rated at 32 watts compared to the 40 watt rating of T-12 lamps, and yet provide the same level of illumination.

Using the more energy efficient T-8 lamps in all buildings has resulted in electrical cost savings for lighting and conserves valuable resources. The T-8 lamps are rated at 32 watts; the older T-12 lamps were rated at 40 watts; this is a 20 percent energy savings. In addition, the new T-8 lamp provides a higher quality of illumination than the T-12 lamp it replaces.

Metal Halide Lighting Conserves Energy

For Exterior Lights Retrofit with White Metal Halide Lamps

Considerable energy savings can be achieved by using Metal Halide fixtures for outdoor lighting. Metal Halide, (MH), lamps, which are white and show colors correctly, offer significant energy savings over standard incandescent lamps. As an example, consider that a 32-Watt MH lamp can replace an incandescent bulb in the range of 100 to 150 Watts, thus saving over 50 percent in outdoor lighting costs.

Replace Mercury Vapor Lamps with Metal Halide Lamps

You can replace mercury vapor lamps using a ballast retrofit kit or a new fixture. A 100-Watt metal halide lamp typically replaces a 175-Watt mercury vapor bulb, thereby saving roughly 40 percent in outdoor lighting costs. Costs and savings will vary at your facility based on the specific wattages and usage of light fixtures (we have estimated that outdoor lights are used 8 hours per day).