Energy-efficient indoor and outdoor lighting design
Indoor Lighting Design
When designing indoor lighting for energy efficiency, consider some basic design principles and methods.
Energy-efficient lighting design principles include the following:
- More light is not necessarily better: light quality is as important as quantity
- Match the amount and quality of light to the performed function
- Install task lights where needed and reduce ambient light elsewhere
- Use energy-efficient lighting components, controls, and systems
- Maximize the use of daylighting.
Here are some basic methods for achieving energy-efficient indoor lighting:
- Install fluorescent or LED light fixtures for all ceiling- and wall-mounted fixtures that will be on for more than 2 hours each day, such as kitchen and living room, bathroom, hallway, and other higher-demand locations.
- Consider installing fluorescent or LED fixtures, rather than using fluorescent or LED replacement lamps in incandescent fixtures.
- Use CFLs or LEDs in portable lighting fixtures that are operated for more than 2 hours a day.
- Use occupancy sensors for automatically turning on and off your lights as needed.
- Consider light wall colors to minimize the need for artificial lighting.
- If you are using recessed lights in a ceiling with an unconditioned space above it, use only Underwriters Laboratory (UL) approved fixtures that are airtight, are IC (insulation contact) rated, and meet ASTM E283 requirements.
Outdoor Lighting Design
When designing outdoor lighting, consider the purpose of the lighting along with basic methods for achieving energy efficiency.
Outdoor lighting for homes generally serves one or more of three purposes:
- Aesthetics: Illuminate the exterior of the house and landscape
- Security: Illuminate the grounds near the house or driveway
- Utility: Illuminate the porch and driveway to help people navigate safely to and from the house.
Here are some basic methods for achieving energy-efficient outdoor lighting:
- Security and utility lighting does not need to be bright to be effective.
- Use LED or fluorescent lights unless incandescent lights are automatically controlled to be on for just a few minutes each day.
- Consider flood lights with combined photo sensors and motion sensors in the place of other security lighting options.
- Make sure outdoor light fixtures have reflectors, deflectors, or covers to make more efficient use of the light source and help reduce light pollution.
- Use timers and other controls to turn decorative lighting on and off.
- Use outdoor solar lighting where applicable.
The light-emitting diode (LED) is one of today’s most energy-efficient and rapidly-developing lighting technologies. Quality LED light bulbs last longer, are more durable, and offer comparable or better light quality than other types of lighting
LED is a highly energy efficient lighting technology, and has the potential to fundamentally change the future of lighting in the United States. Residential LEDs — especially ENERGY STAR rated products — use at least 75% less energy, and last 25 times longer, than incandescent lighting.
Widespread use of LED lighting has the greatest potential impact on energy savings in the United States. By 2027, widespread use of LEDs could save about 348 TWh (compared to no LED use) of electricity: This is the equivalent annual electrical output of 44 large electric power plants (1000 megawatts each), and a total savings of more than $30 billion at today’s electricity prices.
How LEDs are Different
LED lighting is very different from other lighting sources such as incandescent bulbs and CFLs. Key differences include the following:
- Light Source: LEDs are the size of a fleck of pepper, and a mix of red, green, and blue LEDs is typically used to make white light.
- Direction: LEDs emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light. This feature makes LEDs more efficient for many uses such as recessed downlights and task lighting. With other types of lighting, the light must be reflected to the desired direction and more than half of the light may never leave the fixture.
- Heat: LEDs emit very little heat. In comparison, incandescent bulbs release 90% of their energy as heat and CFLs release about 80% of their energy as heat.
Info: Originally Energy Saver is the U.S. Department of Energy’s (DOE) consumer resource on saving energy and using renewable energy technologies at home. Learn more about the Energy Saver Mission.