An energy efficient way to light up a garden, deck, or walkway

Outdoor LED lights can be a cost effective and energy efficient way to light up a garden or back yard. Whether you are looking for accent lighting, powerful security lighting, or just a way to find your way to the bike shed after a late ride, LED lights will provide better efficiency than any other choice. But before you spend a fortune on LED landscape lights or turn your garden into an evening light show, think about the total energy costs of using outdoor LED lights. Too much efficiency, it turns out, can be a bad thing.

Many buy LEDs to light up their yard because they know LEDs are environmentally friendly and use little energy. But have you noticed how people seem to put up more and more strings of LED Christmas lights every year – until they might have ten times more LED bulbs than they used to have incandescent bulbs?

This shouldn’t surprise us: the new lights use a lot less energy so we can afford to put up more of them. This phenomenon is known as the “Jevons paradox”, a phenomenon first noticed by 19th century economist William Stanley Jevons, who argued that the increased efficiency of steam engines would lead to the consumption of more coal, not less, because lower operating costs would drive new uses of steam engines. The same thing seems to be happening with outdoor LED lights.

Sure, it’s environmentally friendly to upgrade outdoor incandescent lights to outdoor LED lights of the same light output, provided you don’t change the amount of time you leave them on. But just as it’s more environmentally friendly to stop driving, than to drive a Prius, it’s also more environmentally friendly to not light up your entire yard than to light it up bright as day with outdoor LED lights. And bear in mind that those LEDs use energy not just when you turn them on, but in their manufacture, delivery to the storefront or warehouse, and disposal at the end of their useful life. And if you look for low cost outdoor LED lights there’s a good chance you’ll be tossing your lights out not too long after you buy them.

I have friends who set up an elaborate LED yard lighting system. Their garden looks great when you’re on their back patio on a summer evening. But because it uses so little power, they leave it on every evening for four hours, for that occasional five second glance outside. Their total energy cost might only be a few cents a day, but it seems wasteful to me to leave lights on for four hours so you can have one quick look at them!

How about security lighting? LED security lights are definitely a low-cost way to light up an area you want to keep intruders away from. But did you know that security lights not only increase the amount of light pollution in our cities (an important factor for the star gazers among us) but may well draw the burglars to your house, rather than frighten them away?

Choosing LEDs – power source, voltage, purpose

Outdoor LED lights can be classified according to their power source, their voltage, and the use they will be put to.

Power source

Solar-powered outdoor LED lights use small solar panels as their power source. Typical LED landscape lights can be presed into the ground along a garden walkway, or in your lawn; they convert sunlight to electricity during the day, store it in a small battery, and power the LEDs at night using the stored electricity. LED security lights are another option that can be powered by the sun.

Grid connected outdoor LED lights obviously need to be plugged in, so you’ll be paying for the electricity they use, but you won’t have to worry about whether there’s enough sunlight to power them, and you won’t have to deal with the tendency of solar powered LEDs to grow dimmer over time as their batteries weaken.

The last power source to consider are battery powered outdoor LED lights. These are a great choice where you don’t have good access to sunshine to charge a solar LED light, and don’t have access to an electric outlet for plug-in LED lights. Battery powered outdoor LED lights are a great solution because even a small, disposable battery, or a regular rechargeable battery, can give you hundreds of hours of light on a single battery or charge.

Voltage

Plug-in LED lights typically come in either 120V AC (120 volt alternating current), which allows you to plug them directly into an ordinary electrical outlet, or 12V DC (12 volt direct current), which requires a power converter. 12V DC outdoor LED lights were once the norm but have lost ground in the last two years, because 120V outdoor LED lights are easier to connect to the grid. Many configurations of outdoor LED lights that were once only available in 12V are now easily obtained in 120V. Of course if you build a DIY solar powered outdor LED lighting system you’ll probably want to stick with 12V DC lights since solar panels produce low voltage DC power.

Purpose

Consider what use you will put your outdoor LED lights to: are they for security, for safety and utility, or for setting or appearance?

  • Security outdoor LED lights provide light to dark areas such as a lane, entrance to your house, or any other area where you are trying to deter unwanted visitors. Most have motion sensors so they turn on when someone (or something) approaches them. Motion-activated LED lights can also be useful to light the way in a dark area without leaving the lights on continuously.
  • Safety/utility lights brighten up outdoor areas so they can be used safely and effectively. LED flood lights, for instance, can light your garden for an evening meal, although they won’t necessarily provide the greatest ambiance. A solar powered LED light can illuminate a garden shed, if you find yourself going in there in the dark (for example to put a bicycle away after an evening ride). And you won’t need to run an electrical line to the shed from your breaker panel.
  • Outdoor LED lights to create ambiance might be ground-level LEDs that light up a path or fence or other features of your garden or yard. LED rope lights strung along a fence, or LED Christmas lights strung on tree branches, fall in this group too. They add to a setting but aren’t strictly necessary. If you really want to save energy – as I hope most visitors to this website are – you’ll want to cut down on unnecessary energy use.

More on power source

Solar power is one obvious power source for outdoor LED Lights.

One of the best energy saving features of outdoor LED lights is that you can use free solar power. The market is flooded with inexpensive LED lighting systems that include a small photovoltaic cell, built-in battery storage, and LEDs. They charge during daylight, and when the sun goes down, on go the LEDs.

About ten years ago I started seeing an infestation of green path lights cropping up like mushrooms in neighbors’ front lawns. These lights were generally a lantern on a stake, with a tiny (and very cheaply made) solar cell on top. They were either green or stainless steel, and the light they put out was typically faint in the evening, and nonexistent a couple of hours after the sun had set. These lights were usually incandescent but late entrants included some fluorescent models, which could last a little longer after sunset but cost quite a bit more.

Why did these units work so poorly and throw off so little light?

  • The photovoltaic modules on these lamps are low-quality cast-offs. How else can your local discount store sell them for $10 for a set of 4?
  • Ditto with the built-in rechargeable batteries: low-cost, low-quality. They don’t hold a good charge for more than the first few weeks.
  • The lights are incandescent (very inefficient) or fluorescent (four times better than incandescent, but still not nearly as efficient as outdoor LED lights), so they quickly drain the little power the small, cheap solar cells caputered and stored in the small, cheap batteries.

Solar LED landscape lights have a built-in advantage on both the solar cell and battery front, because they use so little power. At the same time, they have benefited from steady improvements to both solar cell technology (as prices drop, the quality of the solar cell going into an outdoor LED landscape light can go up for the same input cost) and rechargeable battery technology. Of course, if you stick with the cheapest solar outdoor LED lights you can find – say $10 for a set of 4 LED landscape lights – they will probably fail or fade just about as early as the older style models.

You’ll find better quality componentry in most solar powered LED floodlights and LED security lights. They also typically have enough capacity, in terms of both a larger solar panel and better batteries, than the shove-in-the-ground landscape lights. Solar LED floodlights and security lights make sense if you have a location with plenty of sun during the day, and a place to mount the solar array, which can sometimes be a couple of feet across. Remember that even a little shade on one section of a solar panel can significantly lower its capacity. That means that a few leaf shadows from a nearby bush during the day might make the difference between a bright LED floodlight in the evening, and a very dim one. If you’re determined to go solar and the light location isn’t close to direct sunlight, you should buy an LED floodlight or security light where the solar panel is connected to the light by a length of wire. These typically provide at least 6 feet of wire and you can always splice in an extra length if need be.

Solar LED floodlights or landscape lights are a great way to experiment both with solar energy and with LEDs, but you really won’t be saving very much on electricity costs, because LEDs use so little energy. Especially if your outdoor LED lights will not be on for that long – such as a security light that just goes on for a minute whenever it detects motion in your back yard, or a floodlight that you use a few evenings a year to do late evening yardwork – you’ll never recover the added cost of a solar panel and battery, in terms of the electricity you’ll be generating yourself instead of pulling from the grid. Consider even an elaborate outdoor LED light system such as a 50-foot LED rope light, one LED per inch, for a total of 600 lights. The whole system uses just 40 watts, and if used for two hours an evening, 50 evenings a year (for example), you’re only using 2x40x50 or 4,000 watt hours a year (4 kilowatt hours), which will cost you about $0.40 to $1.00 depending on local electricity rates. It will take a long time for the added cost of the solar panel and battery system to make up for that electricity cost.

You might think it odd that an energy efficiency expert advocates not using solar-powered LED lights. But if you have a limited budget for energy efficiency upgrades, at this point I think it makes more sense to lower overall energy use through buying as much of the most efficient LED lighting you can buy (where it’s really needed) than to convert less of your existing lighting to LEDs powered by solar power.

LED lights sold in North America typically come in two voltages: 120 volt AC, and 12 volt DC. You can buy LED rope lights, for instance, in both wattages, so you can build an outdoor LED rope light system using either grid connection or your own home-made solar electric system.

Types of LED lighting: Security, Safety/Utility, Setting

Security LED lights


Solar-powered security LED lights with motion sensors are generally inexpensive, because they are meant to go on infrequently for short periods of time when movement is detected (a burglar, a racoon, a branch swaying in the wind). Because the LEDs are so efficient and the light is seldom on, it’s easy for the system to store enough electricity from the solar panel during the day to meet any night-time demand for light. And for a battery-powered (non-solar) LED security light you can still get a year or more worth of light out of a single battery because the light is on so infrequently.

Of course you might ask yourself whether security lights really do deter burglars (or racoons for that matter). You are providing more light for the burglar to work with; and most people will not notice movement in a lit area as much as they might notice a flashlight moving around an unlit area. The main advantage of security LED lights is that you can find your way safely around without stumbling on or crashing into something. I find the motion-sensor floodlight on the back of my house is useful for night-time trips to the compost heap, but I don’t think it would do a thing to deter a burglar!

If you already have an outdoor security light with an incandescent, halogen, or other bulb, it might make more sense to upgrade the bulb itself to an LED, rather than toss out a perfectly good fixture and replace it with a brand new solar LED security light. But even then it may not make sense from a financial or environmental point of view, to replace a light that is almost never on. If the light is on all night long, then an LED security light will save you money. But if it is motion-activated and not much moves in your yard, you’ll be spending a chunk of money and saving next to nothing in electricity costs. You can use my LED savings calculator to figure out the payback period on any LED investment.

Safety and utility lights

I make a distinction between utility lighting (light so that you can find your way around or see what you’re doing), safety lighting (light so that you can avoid danger such as walking into a metal post) and mood lighting (which just plain looks nice). But it’s okay if your utility lighting or safety lighting happens to look good too. Here are some great options for brightening up your yard, garden or lane with outdoor LED lights for safety and utility:

LED flood lights – similar to an LED security light but without the motion sensor feature – will brighten an entire yard at close to zero electricity cost. LEDs are typically rated for 50,000+ hours of life; even in a hundred years of patio parties you won’t be disappointed! LED flood light fixtures are available to mount to a wall or underhang such as a soffit. You can also buy LED flood lights for bushes or shrubs, which are mounted on a stake that you drive into the ground.


LED rope lights are a good way to light up an outdoor area so that it is bright enough for a social setting. You can line the top of a fence or the side of a railing with LED rope lights to provide safety or mood lighting, or run them along either side of a path so people don’t wander into your tulips on late night strolls. They can easily be connected to the grid (just plug ’em in) and you can buy lengths anywhere from 10 feet to 500 foot reels!

Even a 150 foot reel, with LED lights spaced one per inch, for a total of 1800 lights, consumes as little as 120 watts of electricity. That can light up an entire large patio deck beautifully for less than you’d use on a 150-watt incandescent floodlight.


LED barbecue lights are simple solar- or battery-powered LED lamps you can use to see what’s happening on the barbie when it’s dark out. They clamp to an unheated area on the barbecue unit and you can direct their light down on the grill to check that those grill marks are perfectly aligned, or to test meat for doneness.

LED pond lights can be placed below the water line in in-ground pools or decorative ponds. While this is in some respects more for setting than for safety, keeping a bit of light in the water of your garden pond might help someone avoid falling in. Note that these lights cannot typically be placed more than 3 feet below the water surface in a swimming pool.


LED shed lights are typically solar-powered modules where you place a small solar panel on an outside wall or on the shed roof, facing the main path of the sun, and the light itself at the doorway to, or inside, the shed, so you can find what you’re looking for. Note that if your problem is insufficient lighting during daylight – say your shed is surrounded by trees, as ours is – a less technological solution may be to replace part of the roof with translucent plastic roofing material. This makes sense especially if you’re building a new shed or redoing the roof. But it is surely less work to just throw a self-contained LED shed light onto the shed than rip off an existing roof and rebuild it.

LED garage lights are higher capacity than LED shed lights. I discuss both LED and fluorescent garage lights on another page, Fluorescent garage lights. You can go from a simple replacement of an existing 24″ or 48″ fluorescent tube with an equivalent, but more efficient, LED tube, or you can install a solar unit.

LED lights to spice up the setting

The line between safety/utility and setting is a bit blurry, since being able to see the plate of food in front of you could be a safety issue, while the subdued lighting of a candle at your dinner table could be more for the mood. Since we’re at the dinner table let’s start with options for dining.


LED candles are a great replacement for traditional wax candles, on several fronts. You can place them indoors or out, and not have to worry about wind blowing out the flame on an outdoor table, or smoke from a sputtering wick at an indoor table. They can be mounted on a wall (using a wall-mount candle platform) without risk of fire. And your guests might not even realize these candles aren’t real!

These LED candles are made of a translucent plastic cylinder that looks just like beeswax, with a short black plastic wick on the top (so from above the candle appears unlit). The LED light is inside the cylinder below the wick, and flickers gently. You can leave these lights on for hundreds of hours on a single battery charge. And because the battery compartment and switch are recessed on the underside, you can leave them out in the rain and not damage the circuitry.


You can also use LED tea candles to spread across a picnic table during a meal. One of my big beefs with traditional tea candles is that they burn out so quickly – usually leaving half the wax in them surrounding a drowned stub of a wick. LED tea candles burn for hundreds of hours and leave no waxy mess to clean up afterwards. I even leave one on my dresser at night so that if I go to bed after my wife I have enough light to get ready for bed without waking her.

I’ve seen people put out LED wax candles or LED tea candles at parties, and guests can’t help themselves – everyone has to pick them up and have a look. The LED was candles look and even feel like real wax!

I wouldn’t advise leaving the tea candles outdoors overnight, since unlike the LED wax candles they have a flat base and rain could easily work its way into the circuitry from below.


Umbrella LEDs are another battery-powered option. These units consist of a donut-shaped module that splits into two halves; you clip the two halves together around the shaft of your patio umbrella, and the LEDs project light downward onto the table or space below.

You can either buy the LED donut as a separate unit, or you can buy an umbrella stand that comes with one of these lights. My own recommendation would be to choose the umbrella that best meets your needs, then buy an LED light to go with it – you’ll have far more umbrella selection, and probably more LED light selection to boot.

Inset LED fixtures can be installed in deck/patio floor boards or balustrade posts, most easily when your deck is being built. They look great and if your deck is made of an unusual or particularly attractive wood (such as the sustainably harvested, eco-certified red cedar I built my front porch out of) they can really help accentuate the color or grain of the wood. You have to drill a hole through the wood to install the fixture – if you’re even just a little handy with tools you should be able to manage it.

LED house numbers will let passers-by (and drivers-by) see your street address day and night. These large numbers are lit up by energy efficient LEDs (usually grid connected) and you can order just the numbers you need for your address.


LED landscape lights are the sensible replacement for those ever popular but always dim solar landscape lights sold over the past 10-15 years. They are coming down in price and as I mentioned above, because of the low power consumption of the light emitting diodes they use, and recent improvements in solar and battery technology, they tend to last longer and provide a brighter light. One of my neighbors has a very attractive system of LED landscape lights for her yard. It consists of one solar panel on a stake driven into her lawn, wiring laid down under the sod, and about a half dozen LED landscape lights that are tall metallic cylinders with a light near the top. They tend to stay lit all night long, whereas most of the older style solar landscape lights I see in my neighborhood are usually fading within an hour or so after sunset.


LED post cap lights are caps you can put on the top of 4×4 wooden posts along your patio edge. They are capped like a standard post cap and have a solar chip embedded in the top of the cap to charge the battery during the day. The light is emitted from a glazed section below the cap. These protect your posts from rain damage better than a wooden post cap and provide free lighting at night for years. You can get LED post cap lights in copper, white, or even Tiffany style finishes.

Outdoor LED lights are a great introduction to LEDs

LED technology is constantly improving, and as LED lighting products proliferate, the costs of the basic componentry keep dropping. Whether this translates into lower prices overall remains to be seen; some products, like the LED wax candles, appear to be getting more expensive rather than less so. But the increased availability of outdoor LED lights is a good thing overall, since it will help us cut our energy usage for outdoor lighting.

Those of us who have already started the migration to lower-wattage lights by installing fluorescent lighting, have had to suffer through the typically unattractive, glaring light of our fluorescent bulbs and tubes. Outdoor LED lights, unlike fluorescents, can truly provide a more natural, muted light, which is just what you want for the out of doors.

The only downside, as I mentioned at the outset, is that some people will start using outdoor LED lights where they used little or no lighting before, exactly because these lights are so cheap to operate. We’ve seen this happen with just about every energy efficient technology that has come along, from steam engines to refrigerators (which keep getting bigger as efficiency improves) to cars (which people just drive more as efficiency improves), and unfortunately I expect the same thing to happen with outdoor LED lights. There will be an initial efficiency gain as people replace existing outdoor lights with LED systems, but over time we may well wind up using just as much electricity to light the outdoors with LEDs as we did with incandescent and fluorescent lights before – except things will be a whole lot brighter. Not great news if you’re a stargazer or an efficiency nut like me!

If you’re interested in learning more about LEDs, or just trying a few out, outdoor LED lights might be a sensible place to start. You can see for yourself whether you like the quality and color of light they provide, and you’ll get a sense for how little energy they use, without having to buy high-cost bulbs for indoor use. Remember that LED house lights provide a very directed light, and an LED bulb touted as an appropriate replacement for a given wattage incandescent bulb will often turn out to put off far less light, so they may not be suitable replacementsfor the indoor lights you use now. By trying out outdoor LED lights you’ll get some experience with them and can decide how much upgrading you want to do indoors once indoor bulb prices start to drop, as they certainly will within the next few years.

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