We astronomers are engaged in a long, difficult effort to fight light pollution and regain our dark, starry skies. But do we practice what we preach? Take a look outside your home. Do your fixtures shine light into your neighbor’s window and toward the sky, or do they send all their light onto the ground? Can you see the bare bulbs from a distance, or are they shielded? Do you illuminate your house when no one is awake to admire it?
Reducing the glare from your home’s exterior lighting is a common-sense courtesy to your neighbors, who, like you, have every right to a dark bedroom at night. But it is in your best civic interest as well: to promote a safe, pleasant nighttime environment, many jurisdictions are passing laws that prohibit light trespass, rays that shine from one property onto another. What’s more, “dark-sky-friendly” practices will reduce your electricity bill. How? By ensuring that all your fixtures direct their light onto the ground, instead of spraying it up and all around, you can achieve the desired level of illumination with lower-wattage bulbs. Each watt saved means more money in your pocket.
Home lights waste even more energy (and money) when they shine unneeded throughout the night. Let’s look at converting a 200-watt security light from continuous dusk-to-dawn operation to having it on only when triggered by a motion sensor. Shining all night, it will be turned on about 4,100 hours over the course of a year and use 820 kilowatt-hours of electricity, costing you $82 (at $0.10 per kilowatt-hour) in the process. However, the same light, activated by a motion sensor a few times each night, will shine for no more than about a half hour during darkness and use less than $4 in electricity annually. These remarkable savings recover the $20 cost of a standard motion sensor in the first three months.
Poor Lighting Increases the Chance of Crime
Beyond this needless expense, however, poor lighting may actually increase the chance of crime against your home and family. In its Recommended Practice Guideline 33 (issued in 1999), the Illuminating Engineering Society of North America states: “Too often people associate more light or brighter light with safer surrounds. It can be easily demonstrated that too much light, or poorly directed light, causes a loss of visibility.”
When you look toward a glaring, poorly shielded fixture, the pupils of your eyes constrict in response to the bright light — despite being in otherwise dark surroundings. As even novice skywatchers know, your eyes then require several minutes to readapt before they can again see properly in the dark. Such glare can temporarily incapacitate your vision, making it uncomfortable (if not impossible) to view anything near its bright source. Worse, overly bright lights cast harsh shadows in which intruders can hide from view.
A shielded fixture with a lower-wattage bulb, on the other hand, disrupts your dark adaptation less and allows you to see more of everything around you. Arranging your home’s lights for evenly distributed illumination will minimize harsh shadows. And, of course, your eyes will adapt to the dark faster as you leave the proximity of your house.
Let’s face it: for most homeowners, an outdoor-lighting “makeover” is long overdue. With this in mind, we researched more than 20 manufacturers of residential lighting, talked to lighting contractors, and visited major U.S. retailers to create a consumer guide to purchasing dark-sky-friendly light fixtures.
Before heading to the hardware store, consider what you are trying to illuminate and why. Is your lighting for security, increased visibility, or aesthetics? Do you really need to cover your entire yard, or just specific areas next to your house? The intended use of the light affects how bright it needs to be. Usually low-wattage fixtures suffice for an entryway or for decorative illumination, while something stronger might be warranted to light up a patio or parking area. As shown below in “Bulb Basics,” some sources create light more efficiently — or have longer lifetimes — than others.
The intended purpose also determines how long a fixture should remain on each night. For example, you may have decorative lighting to accent your home’s exterior or landscaping. If so, consider installing a timer so it operates only while members of your household are awake.
With few exceptions, no security light needs to be on from dusk to dawn. Unless you’re in the habit of looking out your bedroom window all night long, such continuous operation merely provides the means for a criminal to survey your home’s exterior from afar or, worse, to show where to break in. If you’re concerned about safety, choose a motion-sensing fixture, because by turning on it alerts you and your neighbors that someone (or something) is moving around outside. Most models have manual override switches to keep them turned on (or off) continuously.
Ideally, everyone would choose to install full-cutoff fixtures, which emit no light above horizontal. Let’s be realistic, however. Most homeowners are unlikely to put up poles in the middle of their yards just so they can illuminate the surrounding areas with full-cutoff lighting. Instead, you’re going to attach a fixture to the side of your house, then point it to shine the light outward. So if illuminating your entire yard is important, at least try to minimize the damage: aim the fixture and use glare shields to fine-tune exactly where the light shines, and place it high on your house so that it can be aimed down as much as possible and still illuminate the yard. Attach the light to a motion sensor, and always use the lowest light output that you need.
Sometimes the offending light isn’t yours but a neighbor’s. Obviously, such situations need to be approached diplomatically. Offering a little guided tour of the night sky through your telescope can be used to bring up the subject, or you can always take a more direct — but friendly — approach. (Don’t forget to emphasize the possible cost savings.) If your neighbor agrees that some modification is in order, you could try to shield the existing light. Unfortunately, shields are almost never available for residential outdoor lighting — you will probably need to fashion one yourself. If it’s worth it to you to have glare-free nights, just consider buying your neighbor a new fixture!
|Bulb Type||Watts||Mean Lumens||Lifetime (years)1 dusk-to-dawn||Lifetime (years)2 motion-sensor||Power cost 1-yr3 (d-to-d)||Power cost 1-yr3 (m-s)||Power cost 5-yr3 (d-to-d)||Power cost 5-yr3 (m-s)|
|1Based on an average use of 11.25 hours per day (4,100 hours per year). 2Based on six 5-minute cycles per night. 3Based on actual wattage used by fixture and electricity costing $0.10 per kilowatt-hour. 4Initial lumen output is 4,100; output decreases significantly over time. 5Long warm-up time precludes use in motion-sensor applications.|
Roaming the Aisles
Three categories of exterior lighting await you at your neighborhood home-improvement store: "security," decorative, and path. Unfortunately, many outdoor-lighting offerings control their output poorly and waste energy needlessly, so learn to discern the good from the bad by asking questions and examining various fixtures carefully. But if you must choose from among the "lesser of evils" that you find at local retailers, here are some basic guidelines:
Ask for "glare-free" or "neighbor-friendly" lights — many retailers and manufacturers were confused when we mentioned "dark-sky-friendly" or "full-cutoff" fixtures.
Look for fixtures that direct the light where you want it - down, toward the ground. These will have an opaque cover that hides the bulb itself from view to the side, or they may have glare shields.
Buy lights with motion sensors, if possible, or buy one that allows you to attach a motion sensor yourself.
Be wary of a fixture that merely claims to be dark-sky friendly. Determine for yourself whether it will create glare, or is simply too bright for your intended purpose. (Note that "Energy Star" fixtures contain energy-efficient bulbs, but they still may shine much of their light toward the sky.)
Remember that fixtures are frequently marked with the highest-wattage bulb that they accept — but choose instead the lowest wattage that you need.
You may have some luck finding a dark-sky-friendly security or area light, as a few good ones have been introduced recently. In any case, look for the lowest-wattage floodlights possible (as mentioned earlier, an excessively strong source can do more harm than good), and if you have to angle the floodlight slightly upward, attach a shield so that the light goes only where needed.
If you're determined to have a light stay on all night, consider dual-brightness fixtures with motion sensors; these shine at partial brightness until activated by someone walking by, at which point they temporarily switch to full intensity. Expect to spend $35 to $50 for a good area light and $10 to $90 for a motion sensor with floodlights attached. You can also buy motion sensors alone ($10 to $60) that can be screwed or wired into your existing fixtures.
Good decorative fixtures are much harder to come by. Designed to look nice in daylight, almost all have glass sides that expose the glaring bulb to direct view and spill light in all directions at night. So if you must have these outside your home, base your purchase on performance, rather than good looks alone, and use low-output bulbs. Hampton Bay (Heath Zenith), Regent, and Surveillance brands all offer $30-to-$50 decorative fixtures equipped with motion sensors, or you can attach a sensor to your existing light.
Path lighting is least problematic from the dark-sky standpoint. Closely spaced and low to the ground, these lights use low-output bulbs and tend to be well shielded. Individual fixtures run from $6 to $70, and many are solar powered. But displayed along with these you’ll often find landscape lighting, which is used to illuminate trees and buildings from the ground up. They send most of their light skyward — hardly dark-sky friendly — though many models use low-wattage bulbs. If you use landscaping lighting, whenever possible place the fixtures well above ground level (look for tree mounts) so that the light shines down, and place the lights on a timer so that they are on only when people are around to admire them.
You may not find a specific fixture on the store’s shelves. However, both Lowe’s and Home Depot allow you to special order any product that their manufacturers offer; Lowe’s even has catalogs in the aisle for your perusal. Sears Hardware maintains a “buy list” from which you can order. You can also head online to search for fixtures that are truly dark-sky friendly.
As you might expect, visits to retail stores across the U.S. turned up a wide variety of outdoor-lighting offerings. The largest retail chains — Home Depot, Lowe’s, Wal-Mart, and Sears Hardware (Orchard Supply Hardware in California) — tend to carry well-established product lines, though the items in stock vary from region to region. In most cases the ones described below are only examples; there exist many acceptable variations on these themes.
Floodlights and area lights. The Heath Zenith Decorative Halogen Motion Sensing Security Light (SL-5597; $40 at Home Depot) is one of the few shielded motion-sensor lights we found. It has a 240° detection zone, adjustable 15- to 100-foot range, manual override, and 10-year warranty. Thanks to its innovative “Dual Brite” feature, you can choose to have the light turn on at dusk at a low level. It will momentarily brighten whenever someone walks by, triggered by a motion sensor. Then, three or six hours later (once everyone is in bed), its motion-sensing electronics revert to all-or-nothing operation.
Online option: RAB sells the Stealth Sensor with two floods for $90 on eLights.com. Shields cost $8 each.
Many motion sensors can be purchased separately to install with an existing fixture. One example is the Regent 180° Motion Sensor (MS180; $20 at Lowe’s). It has a broad detection zone, a range of up to 70 feet, manual override, and 5-year warranty. Regent also makes a 240°, 10-year-warranty version for $25; RAB sells sensors with a few more features on eLights.com for $39 to $60; Heath Zenith makes a line of motion-sensing adapters for both flood and decorative fixtures.
If motion-sensor lighting won’t work in your situation, try using a timer. Unfortunately, there are few outdoor timers from which to choose. (In fact, some models we saw had been on the shelf so long, their batteries had corroded.) The Intermatic Heavy-Duty 24-Hour Outdoor Timer (HB31R; $18 at Home Depot) permits two on-off cycles per day and comes with an override switch.
Other options: Outdoor Lighting Associates sells DPN Photocontrol for $50. This creative alternative to dusk-to-dawn lighting will keep your lights turned on for exactly half the night.
A recent entry in the home-lighting market is the GlareBuster (GB-1000, about $60), manufactured by Lighting by Branford. Light-pollution activist Bob Crelin teamed with his longtime friend, lighting engineer Perry Maresca, and Peter D’Engenis to create a true full-cutoff fixture that homeowners can easily install themselves. The GlareBuster accepts various standard bulbs, comes with an adapter for mounting on siding (eave mount available), and can be outfitted with a motion sensor. Unfortunately, the GlareBuster is not yet available in any retail chain, though it is available through a growing number of independent dealers.
Other options: Regent makes two area lights with full-cutoff designs. The sleek RSM100 ($35 at Lowe’s) comes with a 100-watt mercury-vapor bulb, while the dome-shaped LP175 ($49 at some Lowe’s stores) has a 175-watt mercury-vapor bulb. However, these high-output bulbs will be too strong for many homeowner applications.
If replacing your existing fixture (or your neighbor’s) is not an option, it may be possible to buy or make a shield for it. One common light, sold by many retailers, is a dusk-to-dawn fixture in a quasi-cylindrical enclosure with a mercury-vapor bulb of 100 to 175 watts. These are legendary for the amount of glare and waste they produce — one manufacturer even calls its model the “Yard Blaster.” If you have one of these, or must endure one installed by your neighbor, help is now available.
Since 1994 Hubbell Lighting has produced a hemispherical shield known as the SkyCap (NPU-BI). This all-metal attachment turns this style of security light into a full-cutoff fixture. Unfortunately, Hubbell sells its products almost exclusively through commercial distributors. But a version of the SkyCap is available (NH1204; $35 plus $10 shipping) from Green Earth lighting. David Oesper, GEL’s former owner, has added a centering ring to ease installation, provide proper alignment, and make it more durable in adverse weather. Hubbell also incorporates the SkyCap in its series of complete Nite-to-Lite fixtures ($201 from Green Earth Lighting).
Decorative & Pathway Lighting
Decorative exterior lighting. After despairing that no decorative full-cutoff lights were available in major retail stores, we found one that comes close. The Heath Zenith Security Wall Light (SL-5630; $50 at Home Depot) uses a combination of shielding, internal reflectors, and Fresnel lensing to control the output from its 100-watt halogen bulb.
A few other good fixtures were found through online searches. Plow & Hearth offers the Old Brooke Light ($30 to $100) in three sizes, which allows for placement from next to your front door to above the garage. The same company also sells a full-cutoff Country Lamp ($125 to $200).
Path and landscape lighting. One commonly available offering is the Malibu Solar-Powered Accent Light (LZ1D; $10 at Home Depot, Lowe’s, Wal-Mart, and Sears Hardware). Its energy-efficient LED emits only a few lumens, throwing a soft glow onto its immediate surroundings. The installation is easy (just plug in the batteries and stick it in the ground), though you may have concerns about the durability of these plastic fixtures.
Another product is the Twilight Low Voltage Tuscan Path Light (TTG-104; $17 at Lowe’s). The Tuscan is a full-cutoff, low-voltage fixture that connects to your house for electricity (as do most path-lighting systems). Such low-voltage applications are safer than household current; also, they are not regulated by local building codes and do not require a special underground conduit. But you do have to purchase a transformer ($33 and up) separately.
Nightscaping sells and installs products through professionals that use minimal lighting to achieve your desired effect. We were impressed by the Deckliter, a little unit that hides under your eaves and illuminates a deck or patio as would the full Moon, and the versatile Turtle, which can sit on the ground as a path light or be a full-cutoff sconce on the side of your house. However, these quality fixtures come at a price: basic multiple-unit installations run from $1,500 to $5,000.
A Less-Bright Future?
Residential outdoor lighting has far to go. We would all like to see retail shelves stocked with full-cutoff, energy-efficient lighting fixtures. But this change must come on all fronts — from manufacturers, retailers, and consumers alike.
Sadly, some manufacturers still have little appreciation for the many benefits of dark-sky-friendly fixtures. When contacted by Sky & Telescope about “full-cutoff” or “glare-free” lighting, many company representatives had no idea what we were referring to — some even believed that we wanted their potent dusk-to-dawn lights. Home lighting, it seems, is rarely designed to the exacting photometric specifications that are the standard for commercial lighting; most residential fixtures just hold a bulb.
There are exceptions, of course. The Regent brand (now owned by Cooper Lighting) now includes a few “neighbor-friendly” and “dark-sky lighting” products. Heath Zenith was the most helpful manufacturer in tracking down which dark-sky options they did offer. And resourceful amateur astronomers like Bob Crelin and David Oesper have come forward to fill an obvious need.
The key with retailers, it seems, is to make your preferences known. On the floor of one Home Depot store, a sales associate noted that frequent demands for a certain product can convince the regional buyer to purchase and stock the requested items. Retailers are willing to change, and residential lighting will improve if consumers insist on low-glare lights. Only then will both the retailers and the manufacturers respond.
Fortunately, the consumer-lighting industry is beginning to get the message. “We’re trying to focus more attention on dark-sky issues,” notes Rebecca Rainer, a marketing manager at Cooper Lighting who works on new-product development. (Cooper’s Regent and Lumark lines are sold extensively at major home-improvement stores.) She says retailers are now pushing for a product line that includes full-cutoff fixtures — especially in areas of the U.S. where light pollution has become a topic of discussion and legislation. According to Blake Aldridge, marketing manager for DESA International’s Heath Zenith products, motion-sensor fixtures now dominate the sales of security lighting for homeowner use. “It’s a more intelligent choice,” Aldridge says.
But reversing the tide will be a slow process. Consumers are still drawn to the lowest cost, which all too often translates into strong, glary lights with little or no shielding. Now that compact-fluorescent bulbs are gaining widespread acceptance as an energy-efficient alternative to incandescent sources, they are beginning to see use in outdoor fixtures. Unfortunately, these bulbs do not handle rough weather or cold temperatures well. Rainer says that a new lighting product, once approved, can take anywhere from one to two years to design, produce, and distribute. That said, both Cooper and Heath Zenith plan to introduce new low-glare fixtures for homes. Watch for them at a store near you!