Attractive, well-placed lighting makes decks safer as well as more inviting. Many deck-lighting selections aren’t complicated to wire, notably energy-efficient low-voltage systems, so there’s little or no reason why builders should not add lighting to their repertoire.

Most deck and landscape lighting systems run on 12-volt current, not the 120-volt line current that household lighting fixtures typically use. (For a detailed overview of wiring, see “Wiring for Low-Voltage Lighting” in the March/April 2008 issue of Professional Deck Builder, free at

Low-voltage systems are safer, with a much lower potential for electrical shock (some installers would say no potential). It’s relatively easy to add new fixtures to an existing system, and in most jurisdictions the installer does not need an electrician’s license. Light output isn’t as robust as it is with a 120-volt system, but then, electrical consumption is lower.

Solar-powered fixtures are another option (Figure 2). Their big advantage is convenience: Mount them on the rail or post and let sunlight do the rest. Solar cells recharge AA batteries inside the fixture, which power the light at night. There’s no wiring to worry about.

But solar deck lights have some disadvantages, too. The batteries have to be replaced after about 500 charge cycles or 18 months of operation. Meanwhile, solar fixtures don’t throw as much light as low-voltage fixtures, and stretches of stormy weather make that problem worse.

Steve Hodes Jr. got into the light-fixture business several years ago after watching a hailstorm demolish some copper deck lights he’d just purchased. The experience prompted him to start making his own line of sturdy metal light fixtures — including some with solar panels — that he sells through his Kansas City–based business, Moonlight Decks.

Even if the housing is well made, Hodes says, the solar cells are guaranteed by his supplier for only one year, and the rechargeable batteries, which will have to be replaced periodically, are about $3 each.

“I usually tend to steer people to low voltage if they’re willing to do the installation,” he says. “It’s going to take a little more effort to get those low-voltage ones in there, but in the end it’s going to be less of a hassle.”

Jason Paulk, a landscape-lighting contractor who owns Nite Time Decor in Atlanta, also encourages customers to look at low-voltage systems despite the convenience of solar-powered fixtures.

“I highly discourage using solar lighting for any application at all where you want functional output,” he says. “I would say of the systems that we come in to repair or replace or evaluate, probably 75 percent have some component of solar lighting, and every consumer I’ve dealt with is unhappy and wants to have them changed.”

Subhead: Transformers are the Heart
The heart of a low-voltage deck-lighting installation is a transformer, a device that steps 120-volt current down to 12 volts and distributes the power either to individual fixtures or to hubs that supply groups of fixtures. Transformers are rated by the maximum amount of electricity they can nominally carry.

Voltage drops as the distance to the fixture increases. When it falls too far, light output is noticeably compromised. To compensate, use a transformer equipped with “taps” for different voltages. Output from a multi-tap transformer might range from 12 volts up to 22 volts; the installer selects the appropriate tap for the number of fixtures and the length of the run.

Unique Lighting Systems, which makes transformers as well as light fixtures for decks, advocates a hub wiring plan to minimize voltage drop (Figure 3). The transformer powers a hub that feeds electricity to individual fixtures, which are more than 25 feet away.

Kyle Trotter, the company’s national sales manager, says choosing the right tap is important for performance. For incandescent halogen bulbs, for example, voltage should be no less than 90 percent of the bulb’s rated capacity, or 10.8 volts for a 12-volt lamp. Checking the hub with a multi-meter while the lights are on should show whether the tap selected at the transformer is the right one.

Unique Lighting is developing a 24-volt transformer for landscape and deck lighting systems that Trotter says will power twice as many lamps on the same circuit because of lower amperage, with less voltage drop between fixtures.

Paulk compares the hub approach to a zoned irrigation system. By grouping sets of fixtures and feeding each hub separately, fixtures are guaranteed to get the right amount of power, whether they are 5 feet or 100 feet away from the transformer.

Good-quality transformers have an internal fuse that can be replaced and sturdy lug-style electrical connections. These features make high-end transformers considerably more expensive than economy brands ($350 to $400 vs. $80 for a 300-watt transformer), but installers say the improved reliability and performance make the higher price a bargain.

Lights for deck fixtures are typically halogen or xenon lamps, which are both incandescent. Xenon bulbs aren’t as bright as halogens, but they can last up to 20,000 hours and, unlike halogens, can be handled with bare hands without shortening bulb life. They don’t produce as much heat as halogens, and the color temperature of the light is a little warmer (although still cooler than a standard incandescent bulb). Xenon lamps also are less likely to discolor plastic lenses in light fixtures.

But the future will probably be lit by light-emitting diodes, or LEDs, which last far longer and use less electricity than incandescent lamps (Figure 4). A LED may last 50,000 hours before the light falls gradually below an acceptable level; the most efficient white LEDs produce about the same lumens per watt of electricity as compact fluorescents.
LEDs’ significantly higher cost, lower light output, and off-putting blueish color have been obstacles to wide acceptance. “There are people pushing these LEDs,” Paulk says, “but from what people are used to seeing on landscape lighting, if you were to take them to an all-LED job, people are going to say, ‘Wow, that’s not what I was expecting.’”

That, however, is changing. For example, Kichler Lighting offers LED fixtures, including lights for deck posts and steps, that the company says use about 75 percent less power than incandescent bulbs with similar light output. And the color temperature of the LED-generated light is about 2,800 degrees Kelvin, slightly warmer than a halogen lamp.

Highpoint Deck Lighting also sells a wedge-base replacement LED that draws only about 3/4 watt, compared with the 5-watt to 7-watt incandescent lamps it can replace (Figure 5).

Good looks and energy efficiency make a difference with consumers, but lower costs would give this technology another boost.

Controls are often overlooked when considering outdoor lighting. Typically, individual lights aren’t switched — entire circuits are. Of course there are exceptions, such as task lighting at a grill or standalone solar-powered lighting. How you control lighting depends on the purpose of the lighting. For example, a customer might prefer that safety lighting at a stair come on whenever it’s dark. Such circuits can be controlled with a photosensor that switches on and off at dusk and dawn.

One approach to varying the level of light is to set up several lighting circuits. You can maintain symmetry by alternating the lights on railing posts so every other one is on a different circuit. When the clients want more light, they turn on both. For a romantic mood, maybe just one circuit is all that’s called for.

Putting accent lighting on its own circuit is another good plan, as there may be times when it’s nice to view an artfully lit Japanese maple, for example, without the rest of the deck lighting on.

The increasing variety of lighting may be encouraging more deck builders to give installation a try. After finding that over half its best contractor customers were already installing deck lights, TimberTech last year launched a line of low-voltage deck lights for post caps, stair risers, balusters, and post sides to complement its decking and railing. Some are intended for use only with the company’s products, but others can be used with all brands of decking and railing.

“Lighting is an essential part of the decking category,” says Paul Bizzarri, TimberTech’s vice president for innovation, noting that lighting adds value for the customer because the deck is more attractive and more useful.

Installing deck lighting has the potential for high hourly earnings, says Davis, who started Highpoint Deck Lighting a few years ago as a sideline to his deck-building company. He notes that crews already are on site and don’t need additional permits to do the work. “It’s the most profitable part of the job,” he says.

Scott Gibson is a writer in East Waterboro, Maine.