Lighting a home is not as cheap as you might think. The average American household spends 9% to 20% of its electric bill on lighting, according to the U.S. Department of Energy (DOE). That’s $90 to $180 a year for home lighting, depending on where you live. Americans also spend $11.9 billion a year on lighting equipment, with $2.7 billion of that on lightbulbs.
In the United States, about two-thirds of our electrical energy is produced by fossil fuels, meaning that lighting has a significant environmental impact from greenhouse gas emissions, particulate pollution, spills, and other damages from extraction of coal, oil, and natural gas. With nuclear, there’s also the potential for widespread deadly contamination, and the important issue of disposing of radioactive waste.
Beyond the environmental benefits of improving a home’s lighting efficiency, it is cost effective as well. An analysis by the Energy Cost Savings Council estimates the average payback period for an investment in efficient lighting at 2.2 years, with an average return on investment (ROI) of 45%. That’s a better return than almost any other change you could make to your home.
In 2007, by switching to compact fluorescent (CF) lamps, Americans saved an estimated $1.5 billion and enough energy to light all of the households in Washington, D.C., for 30 years, according to the DOE. That’s like planting 2.85 million acres of trees or taking 2 million cars off the road in greenhouse gas reduction. If every American household replaced one incandescent with a CF, we would save enough energy to light 3 million homes and make greenhouse gas cuts equivalent to removing 800,000 cars from the road.
America lags behind much of the rest of the world in adopting efficient lighting. In Europe, Australia, Israel, East Asia, or Latin America, you’ll see almost exclusively CFs. Before the United States passed the new efficiency standards, most lighting companies already had plans to discontinue mass production of incandescents, and switch to more efficient technologies.
Congress passed the Energy Independence and Security Act of 2007, which requires new general-purpose bulbs to be 30% more efficient than standard incandescents by 2014. By 2020, additional standards require general-purpose bulbs to produce at least 45 lumens per watt (W), about the same as current CFs. Many other countries have similar standards.
Before selecting any lighting, follow a couple of design recommendations. First, keep interior finishes light in color to reflect as much light as possible. Avoid gloss paints or wood finishes with semi-gloss or gloss treatments, particularly for ceilings because the reflective surface can act as a mirror, making an up-lighting application look uneven, with hot spots. Maximize the use of daylight with thoughtfully placed windows, and light wells or solar tubes. Use lighting controls (dimmers and occupancy sensors) where appropriate. (Note that dimming some lightbulb types can be tricky—follow the manufacturer’s recommendations to select the correct dimmer.)
Incandescents are inefficient and short-lived compared to other technologies. They turn only 2% to 10% of the energy they use into useful light and emit the rest as heat. This also heats interior space and can damage art and plants. At about 1,000 hours of use, they have one-tenth of the longevity of CFs.
Halogen. For those who aren’t ready to put the look of conventional Edison lightbulbs (or lamps) behind them, but want a little more efficiency, halogen lamps may be a good start. Halogen lights are a type of incandescent, with the addition of halogen gas and a quartz envelope surrounding the filament. Sometimes this quartz enclosure is surrounded by another glass enclosure to conceal or diffuse the quartz envelope. This also allows you to touch the “lamp” while protecting the quartz envelope. Halogens are 10% to 40% more energy efficient than standard incandescents, and last two to three times longer.
The popular MR16 halogen lamp offers precise beam control and superior color rendition; when dimmed, it shifts to a warmer tone. It is available in an infrared “IR” model, which uses only a modest amount of energy when dimmed. For example, a 12-volt, 37-watt “IR” MR16 dimmed to 50% uses approximately 18 W (similar to a compact fluorescent, but with superior color rendering and a focused directional beam of light). In the energy-efficient home, however, it should be used sparingly—for artwork accent lighting and in bedroom settings where it’s important to dim to the very lowest levels for mood and atmosphere. Incandescent and halogen lamps are continuous-spectrum sources, meaning that they emit light in all ranges of the visible spectrum. When dimmed, these sources shift to the red (warm) end of the spectrum, which can help to encourage relaxation at bedtime (see the “Conserving Your Own Energy” sidebar).
Halogen bulbs are also small, fitting nicely into track light fixtures and under cabinets. The main drawback is that they produce more heat than standard incandescents, and certainly more than fluorescent and LED sources. New “hybrid” bulbs use halogen technology more efficiently but resemble standard incandescents in size, shape, and applications, making them easy replacements in standard fixtures.
Fluorescents come in several flavors: linear fluorescents, screw-in, and pin-base (aka dedicated socket). They are roughly 75% more energy efficient than standard incandescents, and typically last about 10 times longer (10,000 hours). Bulbs have dropped dramatically in price, from around $20 each a decade ago to $7 to $10 for quality bulbs.
To ensure quality, always look for Energy Star-certified CFs, which have a minimum rated lifespan of 6,000 hours and carry a two-year warranty. ES-certified bulbs cannot emit an audible noise. They must produce high-quality light, turn on in less than a second, and reach at least 80% of their output within three minutes. They also cannot contain more than 5 milligrams of mercury (see “Mercury & Fluorescent Bulbs” sidebar).
Fluorescents have come a long way in light quality, with “warm” and “soft white” models from major manufacturers now nearly indistinguishable in appearance from incandescents. It’s important to some to use CFs with the warmest color temperature (more yellow/red—less blue), closer to the warmth of incandescent lamps. A color temperature of 2,700 to 3,000 Kelvin (K) is preferable. The higher range —3,500 to 5,000 K—is best used when a cooler, crisper light is desired. Choose CFs with a high color rendering index (CRI)—how accurately a light source renders perceived color—in the 80s or above only! (The ideal measurement is 100.) CFs do not offer precise beam control. They emit light in all directions much like a standard lightbulb, so they are most appropriately used when a “glow” is desired. Unfortunately, low-quality products have given CFs a bad reputation—cheap lamps can produce poor color-rendering properties, as well as buzz and flicker. They tend to be short-lived and don’t dim easily. Many of the screw-in replacement CFs won’t dim at all; the ones that do may dim to a visible 40% level and then flicker before they shut off. (Never put a standard CF in a fixture that’s controlled by a dimmer even if you never “dim” it—this will shorten the bulb’s life.)
High-quality CFs may cost more, but perform well and can be used in many household applications, particularly when the source is concealed from view—such as under a lamp shade, or behind a wall sconce or pendant diffuser. Stay with name-brand manufacturers such as Sylvania, Philips, and GE to get quality CFs, and look for the Energy Star label.
Frequent switching shortens the lifespan of CFs (by as much as 85%), so consider where you put them. CFs also shouldn’t be exposed to extreme cold, since that makes them turn on slower and decreases their lifespan.
Cold-cathode CFs that lack the coating that typical CFs have work better at lower ambient temperatures, and they switch on instantly, although they aren’t as bright. If your home is wired for DC, like some RVs and off-grid homes, you may be able to use DC CFs, which tend to last especially long (18,000 to 25,000 hours). On the downside, they produce fewer lumens per watt and are rarely brighter than a 25 W incandescent; plus, they cost more ($13 to $35).
It’s not a good idea to put CFs in fixtures subjected to shock, since they break relatively easily. Vibrations also shorten their life spans, although there are some tougher models now marketed for ceiling fan fixtures.
As more states adopt residential energy codes similar to California’s, screw-in CFs will not be in compliance for certain areas of the home. This code requires dedicated or pin-base sockets (preferably 4-pin or GU-24) that are designed specifically for fluorescent lamps.
Dedicated-socket CFs typically perform better than their integrated ballast counterparts—the larger ballast is isolated inside the luminaire, and designed to last longer. It also does not need to be replaced when the lamp burns out. The 4-pin lamps allow for dimming down to 10% and, in specific cases with the proper lamp/ballast/dimmer combination, you may dim to 1%, which is optimal. This last 10% of dimming is critical to the human eye because a fluorescent source dimmed to a measured 1% appears visually to be at 10%. Be aware that a dimmed fluorescent source does not color-shift to a warm (more yellow) tone like an incandescent.
For recessed down-light applications, dedicated-socket CFs are plentiful. For residential use, you will want an airtight, insulation-contact (IC)-rated housing to minimize air transfer between your conditioned space and the ceiling plenum. For the ultimate efficiency, keep recessed down-lights out of the roofline ceiling so that the insulation barrier is not penetrated.
The manufacturers of decorative residential-style pendants, wall sconces, and ceiling fixtures are beginning to include dedicated-socket CF options into their product lines. CF fixtures that employ hand-blown glass or fabric shades with beautiful patterns, textures, and colors can often completely disguise the CF source. When dimmed, most people cannot detect that it’s a fluorescent source.
Linear fluorescent lamps are available in smaller-diameter sizes (T8, T5, and T2), and can be dimmable to 1% with the appropriate lamp/ballast/dimmer combination. The diameter of a fluorescent lamp is measured in eighths of an inch—a T8 is 1 inch in diameter (eight eighths); a T5 is 5/8 inches in diameter; etc.). The old fluorescent lamps which will be discontinued are the T12 lamps.
Linear fluorescents are suitable for applications such as coves, vanity lighting (vertically flanking mirrors), closet lighting, suspended direct/indirect fixtures (kitchens), decorative pendants, under-cabinet task lighting, and indirect up-lighting above cabinetry. Using a concealed, linear fluorescent source to bounce light off ceilings and walls can give a general shadow-free layer of light, and helps balance the directional lighting used to accent artwork and furnishings. The color of the reflecting ceiling and walls affects the quality of the light in the space. Ceilings and walls finished in a warm matte wood material or painted a matte warm color can make the fluorescent source feel more like incandescent lighting. A 3,000 K, high color-rendering linear fluorescent lamp produces a very appealing warm light, which enhances skin tones and can be flattering. Gone are the days of fluorescents that make you look gray and lifeless—if you choose wisely.
Light-emitting diode (LED) lamps are rapidly advancing beyond nightlights, flashlights, and desk lights—categories they already dominate. A 12 W LED replacement A-lamp may be a suitable replacement for a 60 W incandescent, so significant energy savings are possible by switching to LEDs. However, the high cost per bulb is a hurdle for some folks. At $20 to $60 each, they don’t come cheap. Their salvation is that they will last for tens of thousands of hours.