Lighting accounts for as much as 20% of residential energy use. In fact, it's one of the top three energy users in a typical home. Replacing conventional incandescent bulbs (including halogen bulbs) with energy-efficient fluorescent and LED lighting will save money, energy and greenhouse gas emissions. Fluorescent and LED bulbs also last longer, sparing you the hassle of frequent replacement.
Upgrading to more energy-efficient lighting is likely to be one of the easier and more cost effective home improvements you can make. In the past, fluorescent lighting suffered from a reputation of poor quality. But newer fluorescent bulb and electronic ballast technologies have remedied earlier shortcomings. New products have eliminated flicker, deliver instant start times and provide much improved lighting quality.
Making the most of daylight is another eco-friendly lighting option. But as is the case with many good things in life, more isn't always better. Check out our tips for using daylight to illuminate your home without introducing too much glare or heat.
Starting in 2012, light bulbs sold in the United States have to meet new standards for energy efficiency. Bulb packages are now also required to have a standardized "Lighting Facts Label" that will help you comparison shop. This label shows the bulb's brightness measured in lumens; the higher the lumen, the brighter the bulb. It also provides an estimated yearly energy cost, the life expectancy of the bulb, the light appearance (from warm to cool), and the amount of energy used in watts.
Although some incandescent bulbs will meet these new standards, the most energy-efficient choices for home lighting are fluorescents and LEDs:
- Compact fluorescent light bulbs (CFLs) use one-fourth the electricity of an incandescent bulb and last eight to ten years. They come in pin-based and screw-based configurations. Pin-based bulbs only fit fixtures specifically designed to accommodate them. Screw-based bulbs will fit most fixtures that typically take a conventional incandescent bulb.
- Tubular fluorescent bulbs, such as T5s and T8s, are commonly used in ceiling fixtures in kitchens, basements, laundry rooms and garages. The letter T indicates tubular, while the number after the T indicates the tube's diameter in eighths of an inch. A T5 bulb has a diameter of 5/8 inch. In today's new homes, energy-efficient T8 bulbs are common, but many older homes still have the less efficient, wider diameter T12 fixtures. If your home has T12 light fixtures, consider replacing the fixtures with ones designed for T8 tubes. For undercabinet lighting, very narrow T5 tubes are readily available.
- Light emitting diodes (LEDs) have a tiny semiconductor device that converts electricity into light. The technology's strong suit is its durability and ability to create directional light using very little electricity. LED residential lighting is a relatively new and costly technology; as product availability and demand increase in the coming years, prices will likely come down. Because of their directional output and durability, LEDs can be very effective in certain applications, such as under kitchen cabinets and along exterior walkways.
Low-mercury fluorescent bulbs
All fluorescent bulbs (both tube and compact fluorescent styles) contain a small amount of mercury, an environmental toxin that can enter the food chain if the fluorescent bulbs aren't properly recycled at the end of their life. Most manufacturers offer fluorescent light bulbs that contain a fraction of the mercury used in older fluorescent bulbs. Look at the product label for information about whether the bulb has a very low mercury content.
Lighting controls save money and energy by decreasing the amount of time the lights are on, or by reducing light levels. Lighting controls can be installed either at specific locations or as a whole house system.
- Occupancy sensors (also called motion sensors) turn on the light when they detect that a person has entered the area, and turn off the light after a preset period of time after the area is no longer occupied. Occupancy sensors make good sense where the occupancy is intermittent, such as bathrooms, garages, basements, laundry rooms, closets and utility rooms. A similar device is a vacancy sensor. It requires you to turn on the light manually, but like an occupancy sensor, it turns off the light after a preset period of time after the area is no longer occupied.
- Photosensors (also called photocells) can be used to automatically turn lights on at dusk and off at dawn. They're particularly useful for porch lights or other exterior lights and when used in conjunction with an occupancy sensor.
- Dimmers. Electronic dimmers may also help save energy. Some dimmers, however, are mechanical and only cut power to the lamp without reducing the overall power draw. Electronic dimmers can save about 40% of the energy when the lamp is dimmed by 50%. Do not use dimmers with compact fluorescent light bulbs (CFLs) unless the CFL is specifically designed for dimming. Dimmable CFLs cost a lot more than standard CFLs.
- Timers turn lights on and off at preset times. Many people use them to turn automatically switch a few lights on and off each day when the home is unoccupied for an extended period.
In homes designed to use daylight as a light source, daylight can provide illumination suitable for most tasks without the use of electric light. Reducing electric lighting use saves money and curbs greenhouse gas emissions associated with electricity generation. Good daylighting also helps create an appealing indoor environment, and is generally known to elevate people's moods.
Daylighting in homes is typically done through windows, glass doors, skylights and light tubes. If you're planning to remodel a kitchen, bathroom or other areas of your home, take the time to evaluate whether the room's daylighting design can be improved. Here are some tips:
- When building additions or making major changes to the home's floor plan, look for ways to position rooms that are predominantly occupied during the day in the zones that have the best access to daylight.
- Keep in mind that too much window or skylight area isn't necessarily a good thing if it introduces glare or too much heat, or if it provides too little privacy.
- Size and locate windows appropriately. One inexpensive technique for getting daylight deep into a room is to design rooms with tall window head heights (in other words, position the top of the windows so that they are close to the ceiling). In general, a window can provide illumination into a room to a depth of about 1.5 times the window head height.
- Light-colored walls and ceilings reduce glare and get light further into a room.
- On south-facing windows, use exterior shading elements such as awnings sized to shade the majority of the window area in summer and none in winter. This will help keep the south-facing rooms cooler in summer and warmer in winter.
- In general, keep windows on east and west walls as small as possible so the rooms don't overheat in the summer.
- Consider adding fixed or operable skylights wherever windows cannot provide sufficient daylight. Tubular skylights are excellent for top-floor bathrooms and halls.
- Select high efficiency window and skylight products to save money and make your home more comfortable. See our GreenPointer on Windows for more information.
More lighting tips
Look for the Energy Star logo. When shopping for light bulbs, look for the Energy Star label. Energy Star qualified bulbs meet strict energy efficiency guidelines set by the U.S. Environmental Protection Agency.
Recycle it. In California, it is illegal to discard any fluorescent lamps or ballasts in the trash. All fluorescent light bulbs, tubes and ballasts (including low-mercury products) must be recycled by an authorized recycling facility. Check with your local waste and recycling hauler for disposal options.
Choose your color temperature. A light bulb's color temperature is indicated in degrees Kelvin. For fluorescent lamps, a color temperature of approximately 2,700K provides warm, intimate lighting similar to the yellow glow of an incandescent bulb. The light bulb's package may say "warm white." Bulbs labeled "cool white" provide whiter light similar to daylight; they have a color temperature of 3,500K or higher.
Learn the basics of good lighting design. In many homes, some areas don't have enough light, while other areas have too much. A good lighting design uses different fixtures to deliver appropriate amounts of ambient, task and accent lighting to meet the needs of each space in the home. Ambient light provides general light in the space, while task lighting illuminates a specific area, such as a countertop or desk. Use accent lighting sparingly to highlight artwork, bookshelves and decorative objects. Homes are often designed with excessive ambient lighting in hallways and living rooms, and not enough task lighting in kitchens.
In California, the building energy efficiency code (Title 24) requires that at least 50% of the entire wattage in kitchens be permanently installed high efficacy lighting (most incandescent bulbs do not qualify as high efficacy). As of January 2014, the code requires that bathrooms have at least one high efficacy light fixture, and all other bathroom lighting must be high efficacy or controlled by vacancy sensors. With the exceptions noted below, all other interior and exterior residential hardwired lighting must be either high efficacy or use specific controls. Exceptions include appliance lights (for example, a lamp in a range hood), lamps on dimmers, and lamps where the fixture cannot accommodate a CFL (for example, some small wall sconces and chandeliers). These requirements apply to new home construction as well as remodeling projects in California.
An architect, builder, licensed electrician or lighting professional can help you understand the California code requirements. It can be challenging to design lighting for the home that is effective, efficient and attractive. Consider consulting a residential lighting expert such as a Lighting Certified (LC) professional to help with bulb wattage choices and lighting fixture placement; to find an LC professional, go to www.ncqlp.org. For more information about energy-efficient residential lighting, including shopping tips and lighting design advice, visit the U.S. Department of Energy's website, www.energysavers.gov.