Transformers – Use Toroidal, not EI-type Wire Sizing – Either use all 10/2 wire, or size wire according to suggested limits Wiring Configuration – Instead of carrying heavy loads on single wire runs, distribute load of many runs Lamp Wattage – Use the lowest possible wattage for all fixtures Operation Time – Educate the homeowner in the proper use of time clocks and use separate transformers for safety/security zones whenever possible
The size and shape of the core determines the efficiency of this transfer. In lighting transformers there are two such configurations – EI-type and Toroidal. The EI-type core is composed of many laminations (flat layers) of steel. The toroidal type has a ring-shaped core.
Recommended and Mazimum Wire Amp Ratings Wire Gauge Recommended Maximum #12/2 100w/8.3A 192w/16A #10/2 140w/12.0A 288w/24A
The Example – Walking through the steps towards energy conservationIn our review of other manufacturers’ recommendations and from our discussions with installers, we find a number of practices that waste energy. To demonstrate the negative contributions of each of these practices we start with a sample installation that makes all the mistakes, then step-by-step we correct them until, at the end, we finish with the model energy-conserving system.
Lastly, connect all cables to your transformer, plug the transformer in, and enjoy!
Simple Ways to Reduce Energy Consumption in Landscaped Lighting SystemsAuthor: David Beausoleil
Toroidal 1200w transformer (savings – $63.07) All #10/2 wire (savings – $32.28 per year) 5 wire runs @ 80 ft. each and 2 wire runs @ 30 ft. each (savings – $42.41 per year) About half the lamps at 20w instead of 35w (savings $111.
58 per year) All fixtures on single transformer
First, lay out all your components and cables. Be sure to leave extra cable running to each light so you can reposition easily, if needed. Save on cable by finding an outlet close to your lighting needs.
When purchasing cables to connect your outdoor landscape lighting to the transformer, you’ll want to make sure you have enough wire to run the lighting to your power source.
Step 2: Wire SizingAnother source of energy loss is wire. When AC current passes through wire, electrons collide randomly and thransfer their energy (current) along the atoms in the wire. In addition to transferring current, these collisions encounter resistance from the copper atoms that result in the generation of heat. Less heat is generated (energy loss) in thicker wire because there is more space for the collisions. In thinner wire, resistance is greater and a greater proportion of energy is lost as heat.
To determine what size transformer you need, add up the wattage of all the lights on your project. For example, if each light is 5 watts and you have 10 lights, your total wattage is 50. You want a transformer that is 20% larger than what you need. So, for 50 watts, you’d need a 60 watt transformer. We recommend this Kitchler Power Transformer with a Wi-Fi controller and timer.
For more installation inspiration, watch this quick overview on installing landscape lighting, taken from our YouTube channel.
System with Three Improvements: Cost savings – $137.76 per year
Energy Consumption Related to Type of Installer Type of Lighting Installer Energy Cost* (per year, per 25-fixture installation) Energy Hog: Uses EI-type transformers, all #12/2 wire, all 35w lamps and assigns heavy loads on wire runs.
$600.06 Energy King: Uses toroidal transformers, primarily #10/2 wire, at least half of the lamps are 20w and distributes fixtures across many wire runs. $350.86 Energy cost savings per year (per installation) when the Energy Hog changes his ways and becomes an Energy King $249.
20 (1,661 kWh) 30 installations (reasonable yearly estimate per installer)
+ Add together the combined wattage of your individual lights – for example, 5 lights each using 20 watts (5 x 20 = 100).
Tip: Cheap connectors can cause a lot of problems down the road so don’t try to cut costs here. Also, if you need to T-splice your wire, we recommend using DBRY Gel Filled Connectors to keep the wires tight and in a waterproof tube. Avoid DIY wire connectors from your major hardware stores that require you to pierce the wires, as this can create problems down road.
Toroidal 1200w transformer (savings – $63.07 per year) All #10/2 wire (savings – $32.28 per year) 5 wire runs @ 80 ft. each All 35w lamps All fixtures on single transformer
You will also want to pay attention to the recommended and NEC guidelines that specify maximum load on each wire type:
Step 3: Wiring Configuration (Load per Wire Run) Voltage loss, hence energy loss, increases when a few wire runs carry many fixtures/run (higher loads), as opposed to when many wire runs carry few fixtures per run (lower loads).In this example, we reduce the loads on each of the five runs, adding two more (shorter) wire runs to the transformer. The actual numbers of fixtures on each run change from 5,5,5,5 and 5 to 4, 4, 4, 4, 3, 3 and 3.
To demonstrate how this 10% difference in efficiency translates to energy cost, we compare the best EI-type with the CAST toroidal (95% efficient).
You may be wondering, where you can access better quality lighting materials, if you can’t find them at a store near you. That’s exactly why we developed our DIY kits. We’ve selected materials from the best manufacturers, made adjustments to make them more energy efficient and longer lasting, while still cutting costs without sacrificing on quality.
To demonstrate the energy savings benefits of using heavier gauge wire, let’s simply look at replacing the five runs of #12/2 wire in our example with #10/2 wire:
So now that you know where to find the right materials for your landscape lighting projects, you’ll need to know the steps to install it. You’ll save so much money doing it yourself!
We live in an age where energy conservation is paramount. Every landscape lighting installer has a responsibility to make conscious choices to best conserve energy.
Energy Conservation in Low-Voltage Landscape Lighting Installation
You can’t always trust landscape professionals, as they will typically install lighting they get from big box stores. This type of lighting will only cause you problems down the road and require you to constantly be fixing them.
Step 1: TransformersA low voltage lighting transformer steps down a 120v current to 12v. This is accomplioshed in the transformer by winding the primary wire around a steel core in close proximity to a secondary winding leading to the low voltage taps. The primary winding can create a magnetic flux in the steel core that is converted to energy in the secondary wires.
Toroidal 1200w transformer (savings – $63.07) All #10/2 wire (savings – $32.28 per year) 5 wire runs @ 80 ft. each and 2 wire runs @ 30 ft. each (savings – $42.41 per year) About half the lamps at 20w instead of 35w (savings – $111.
58 per year) Fixtures functioning mainly for safety and security on separate transformer from fixtures used solely for decorative purpose; homeowner instructed in operation of timer
Energy Consumption Related to Lamp Wattage Lamping Configuration Total Lamp Wattage Total Watts (Lamps & Wire) Energy Cost* (per year @ 8 hrs. per day) All 35 watt lamps (25 x 35w) 875 1026 $462.44 Half the lamps replaced with 20 watt lamps (13 x 20w) & (12 x 35w) 680 761 $350.
86 Cost savings per year by replacing half the lamps with 20w $111.58 After 5 years $557.90 After 10 years $1,115.80 Additional cost to replace 35w lamps with 20w lamps $0.
= The total is the transformer size, in watts, that you’ll need – a 150 watt transformer in our example above.
More than 100 watts lamps load on runorRun is longer than 100 ft.
After selecting your transformer, your next step is to wire your lights to it. There are two tabs on the bottom of your transformer. One is a common connection and one for 12 volt or 15 volt connection. After you wire your lights into the tabs, you’re ready to mount the transformer, plug it into your GFCI receptacle, and turn it on!
Energy Conservation in Low-Voltage Landscape Lighting Installation
Up and accent lighting – most popular lighting to highlight trees and structures around the property. Wash lighting – to light up stonework and other unique, beautiful features of your home or property.
Path and garden lighting – to light up pathways or plant features. Hardscape lighting – used around BBQ areas, fences, decks, steps, etc.
Use rubber mallet to pound in the lights. Ensure that they are nice and stable to avoid any future damage from getting knocked over.
Efficiency is determined by the sum of losses through wire resistance (copper loss) and losses through the core’s magnetic field (iron or core loss). EI-type transformers vary from 70% to 85% efficient in their conversion of 120v to 12v current,while efficiently designed toroidal types are about 95% efficient. (Note – not all toroidal transformers are well made, less expensive models may have had thinner core wires or be less robust in their assembly.)
For this reason, heavier guage wires conserve energy by allowing the electricity to flow with the least resistance. Ideally, lighting installers would use the heaviest gauge wires for all wire runs. Instead, many installers select smaller gauge wire out of habit, or to cut cost.
The most influential factor in energy conservation is actual operating time. Every transformer installation should have both a time clock and photocell. The photocell turns the lights on at twilight, then the time clock turns off the lights at a time determined by the homeowner. Installers should make sure homeowners understand how to adjust the time clock and advise them to minimize operation time as much as possible.
Depending on the size and layout of your yard, there are different choices when it comes to illuminating your outdoor space. Landscape lights are categorized by usage, style and type – path lights are ideal for illuminating your sidewalk, while spot or flood lights add impressive accents to trees or your home. You can find energy-efficient LED landscape lighting in traditional or modern designs, and in ground lights cast a unique beam of light upward from wherever they are placed.
Extra tips: Pad your numbers. There’s no harm in giving yourself some room to expand on your lighting system. Purchasing a transformer with a higher maximum wattage capacity will come in handy if you want to add more lights later. And, save with LED! Transformers are priced according to wattage, so by choosing low-wattage LED lights, you’ll saveon the bost of both your transformer and your monthly electric bill.
It’s also easiest to run your cables along the ground and place the wire behind plants or lightly cover them with dirt or mulch. Doing so will allow you to readjust them if necessary.
In all lighting designs, there is lighting that serves primarily the goals of security and safety (e.g. path lighting on driveways and walkways and entrance lighting). The homeowner may want these lights on all night or well past bedtime. Other lights that primarily serve the goals of beauty (e.g. lighting on specimen trees, garden beds, and architectural features) may not need to be on late into the night.
Example: A 25-fixture system with an average wire length of 80 ft. per wire run.
Call at 800-782-1967 to speak with one of our friendly, professional Lighting & Home Decor Consultants or visit a Lamps Plus location near you. Whether via phone or in person, we’re happy to assist you in planning your landscape lighting system.
Place the wire at each fixture, leaving extra just in case you need to make changes in the future. Strip the wire with wire cutters and use waterproof gel filled connectors to wire the fixtures. We recommend using these Blazing BVS-2 Snap Lock Wire Connectors to hold wires together nice and strong.
System with Four Improvements: Cost savings $249.34 per year
A collection of the components you’ll need to set up a landscape lighting system. The Three Things You’ll Need: Landscape Lights Transformer Cables Showcasing Your Style: Lights
Your final step is to turn on the transformer to ensure that the lights work. Once you check that everything is working, bury the extra wire, secure the lights, and do any final adjustments to make sure everything looks good. We recommend doing your final adjustments at night, so you have the best idea of how the lights will look before you finish the project. Once everything looks good, bury the wires in your lawn by creating a small trench with a shovel. Push the wire down 6-8 inches deep, then close up the trench by applying pressure with your foot.
EI-type 1200w transformers All #12/2 wire 5 wire runs @ 80 ft. each All 35w lamps All fixtures on a single transformer
Use #10/2 Less than 100 watts lamp load on run andRun is shorter than 100 ft. Use #12/2
Notes: Energy cost is calculated at $0.15 per kWh with fixtures powered 8 hours/day 365 days/yr. Energy calcualations in these examples incorporate the transformer efficiencies; if you are checking these calculation with our online calculator, you will need to divide the final energy cost (from the calculator) by .95 for toroidal transformers and by .85 for EI-types for comparable results.
Landscape lighting can add curb appeal, safety, and security to your home, depending on which type of lighting you choose.
System with Two Improvements: Cost savings – $95.35 per year
Note: the ideal voltage of 12v lamps is between 10.8v and 11.3v.
That’s all there is to successfully installing DIY low voltage landscape lighting. We hope you found these steps and our video tutorial helpful. We are always here to support you with your landscape lighting needs, so feel free to contact us at any time.
All transformers are designated with a maximum wattage capacity. For example, a 150 watt transformer can safely provide power to a circuit demanding up to 150 watts. To start, map out your yard and how you plan to distribute your lighting – a simple sketch works. From there, you’ll have a better understanding of how many lights you’ll be using.
Low voltage landscape lighting is a great way to add value to your home and up its curb appeal while saving you money and minimizing energy use. All you need to get your system installed are the right lights, the proper transformer and cables. If you are looking beyond options that a complete kit offers, here are some tips to make sure you choose the right individual products for your easy-to-install landscape lighting.
We’ve created a video of the steps that you can watch, or you can read the steps below.
6 Easy Steps to Installing Low Voltage Landscape Lighting Step 1: Determine which type of lighting you plan to use
System with First Improvement: Total Cost Savings – $63.07 per year
If you’re looking to affordably install good quality and energy efficient landscape lighting to your home, you’ve come to the right place. While you could call a local landscaping professional to do the work for you, we highly recommend doing it yourself. We can help you every step of the way with the best lighting products, instructions, video tutorials, and support.
Energy Consumption Related to Wire Gauge Wire Gauge Avg. Voltage Drop on Wire Run Total Watts (Lamps & Wire) Energy Cost* (per year @ 8 hrs. per day) #12/2 3.78v 1165 $537.13 #10/2 2.52v 1095 $504.85 Energy cost/year saved after using #10/2 $32.
28 After 5 years $161.39 After 10 years $322.80 Difference in contractor’s price between 500 ft. of 10/2 and 12/2 No-Ox® Wire $45.00
Each landscape light provides a maximum bulb wattage rating. Once you have your total number of lights, follow this simple formula to ensure you pick an adequate transformer:
Tip: To help you decide which lighting to use and where to place it, take a flashlight at night and shine it on features and structures to see what would look good.
As we see from this example, a responsible contractor would install 10/2 wire instead of 12/2 wire with the knowledge that the additional wire cost (that could be passed on to the homeowner) would translate into hundreds of dollars of energy cost savings over the life of the system. This savings is magnified in systems with longer wire runs.With this in mind, many contractors will only use 10/2 wire for every run for every project. However, if you want to continue using 12/2 for shorter runs and for runs with a low wattage load, you can use this simple wire sizing guide:
This effort is in the best interest of the homeowner and society as a whole. If we are to be good steards of the planet, then we must employ best practices during design and installation. The following article focuses on critical lighting system components and installation methods with a view to recognize where energy is lost and where it can be preserved.
Extra tip: Fine tune your lighting placement by checking everything right at dusk. You’ll get a sense of how everything will look at night with just enough residual daylight left to work.
With this in mind, the contractor can employ separate transformers for these two functions. Each one would be set to turn off at the desired time. The energy savings could be considerable.
It’s time all landscape lighting installers rise to the challenge and prove to the people of this country that they are responsible stewards for the planet.
Enery Consumption Related to Transformer Type Transformer Amps on Primary Actual System Watts Energy Cost* (per year @ 8hrs.per day) EI-type (1200w capacity) 85% Efficient 11.42A 1,370w $600.06 CAST Toroidal (1200w capacity) 95% Efficient 10.
21A 1,226w $536.99 Energy cost savings per year using Toroidal Transformer $63.07 After 5 years $315.36 After 10 years $630.72 Cost to upgradefrom EI-type model to Toroidal $38.
The most important step is to think through what you want to achieve: Is it security? Safety along walkways? Ambient decorative lighting? Once you understand what your goals, finding the right landscape lights is easy.
Toroidal 1200w transformer (savings – $63.07) All #12/2 wire 5 wire runs @ 80 ft. each All 35w lamps All fixtures on single transformer
Installing DIY Low Voltage Landscape Lighting in 6 Easy Steps
Energy Consumption Related to Wiring Configuration (Load per Wire Run) Wire Run Configuration Total Length of Wire Total Watts (Lamps & Wire) Energy Cost* (per year @ 8 hrs. per day) Fixtures distributed among 5 wire runs 400 ft.
(Five 80 ft. runs) 1095 $504.85 Fixtures distributed among 7 wire runs 460 ft. (Five 80 ft. runs & Two 30 ft. runs) 1003 $462.44 Energy cost saving per year by distributing fixtures over more wire runs $42.
41 After 5 years $212.07 After 10 years $424.10 Additional wire cost at installation $24.60
“Replacing 120-volt outdoor lighting with 12-volt systems is a growing trend that results in significant energy savings. Further savings can be realized through an intelligent selection of low voltage materials and methods.”
Toroidal 1200w transformer (savings – $63.07 per year) All #10/2 wire (savings – $32.28 per year) 5 wire runs @ 80 ft. each and 2 wire runs @ 30 ft. each (savings $42.41) All 35w lamps All fixtures on single transformer
Setting up landscape lighting is a good idea when establishing the boundaries of an outdoor path.
Connecting outdoor lighting is as easy as plugging a cord into an existing outlet.
The Bottom Line: implementing these energy conservation methods will greatly reduce the homeowners’ energy bills and save this nation millions of kilowatt hours per year.
To bring our example to a close, let’s look at this final table that illustrates the difference between an installed (let’s call him an ‘Energy Hog’) that does everything wrong compared to an installer (an ‘Energy King’) who follows these energy conservation guidelines.
While the turn-off time is completely under the homeowner’s control, there are the following considerations for the contractor.
Step 4: Lamp WattageOne of the biggest mistakes that lighting installers make is in using overly high wattage lamps. We should always remember that the ideal lighting design strategically distributes low levels of lighting throughout the property. When light levels are set too high, the eye adapts to those high levels and sees shadowed areas as black. Lighting designers should keep all illumination at the minimum brightness – just enough to engage the eyes, but not so much as to cause the pupils to contract losing sensitivity to unlit areas.50w MR-16’s are rarely needed (usually only with very tall palm trees that have large canopies). Even with palm trees, 35w is usually sufficient. For smaller trees and bushes, 20w (or even 10w) may suffice. In the case of tall trees, narrowing the beam spread allows you to use a lower wattage. At 32 ft., a 35w narrow (12 degree) MR16 delivers 7.8 fc with a spread diameter of 8 ft. At the same distance, a 50w medium (36 degree) delivers only 4.3 fc.To demonstrate the significance in energy cost savings with reducing lamp wattage, we replace approximately half of the lamps in our example with 20w lamps: