What you need to know
Designing and installing a low voltage landscape lighting system looks easy... buy some lights, some wire, a transformer and hook them up. Unfortunately this is a recipe for frustration - you probably won't be happy with the performance of the system and you will constantly be replacing the bulbs. In addition, a poorly installed system will suffer the ravages of the Florida soil and climate resulting in whole strings of lights failing. This information brochure will tell you what you need to know about landscape lighting so you can be sure your system will work properly and last 10 or 20 years.
Start with a well designed System
The design of a landscape lighting system is part art and part science. It's about understanding how much light is needed and determining where the focal points are. The choice of fixture, bulb wattage, beam spread, placement position and angle for each and every light source are a critical foundation for any successful system. The correct location of the transformers, voltage taps used and wiring routes are vital to ensure every fixture has a bright white bulb that will last its rated life.
Install it with close attention to detail
To create a lighting system that will remain trouble free for ten to twenty years requires good quality components and close attention to detail during the installation. Nightscapers uses computer aided planning and installation techniques that go beyond typical industry practices to ensure your system operates perfectly night after night. An example is the use of soldered joints for the main tee and branch connections. Nightscapers takes this extra step tp completely eliminate one of the most troublesome problems of the system.
Use components that are built to last
There is currently is a wide variety of landscape lighting components available to consumers. The materials used and levels of quality vary considerably and the differences can significantly affect your systems long term operation and viability. Be sure you choose components that are built to last, not those that are built to a price.
Landscape lighting fixtures today are made from a wide variety of materials including plastic, aluminum, copper, stainless steel or brass. While plastic is used in the lowest cost multi-pack systems, aluminum is the most popular material today. Assuming all fixtures made from aluminum are created equal would be an error. Lower cost fixtures are made from aluminum alloys that contain other metal to keep the cost of the material down. This, however, makes it more difficult for the paint to stick to the surface of the fixture resulting in premature paint peeling and chipping, which then allows the soil to corrode the unprotected aluminum itself. Better quality aluminum fixtures are made from a higher grade/purer (also called marine-grade) aluminum to eliminate the paint adhesion problem. Many higher quality fixtures are made from natural copper, brass or stainless steel. As with aluminum there is a wide range of quality to be found.
The paint on lower cost fixtures is simply sprayed onto the fixture and can easily be chipped or scratched. Higher quality fixtures use an electrostatic powder-coating process which is then baked onto the fixture in an oven. This process produces a significantly more durable finish that is practically chip and scratch proof.
When light fixtures are pointed upwards to illuminate trees they are prone to water buildup on the lens. When the water comes from a well or lake fed sprinkler system, the water can contain minerals that will deposit on the lens when the water evaporates in the heat of the day. One popular low cost fixture allows up to ½" of water to become trapped on the lens; in less than two weeks the lens becomes opaque with mineral deposits. It is therefore important to choose fixtures that do not allow any water to become trapped on the lens.
The lens on low cost fixtures is typically window glass. High quality fixtures will employ soda-lime glass which is used in industrial applications for sight-glasses where a clear unobstructed view is required. Soda-lime glass is much smoother that window glass so it helps prevent deposit build-up. It is also much easier to clean the soda-glass glass lens. Mineral deposits on window glass are very difficult to remove without scrubbing and thereby scratching the glass.
The transformer is the heart of a low voltage lighting system. It converts the 120V house current into the safe low voltage to power the lighting fixtures. There is a wide choice of transformers available but some are more set-it-and-forget-it than others. Time clocks without battery backup need to be avoided since they will need adjusting after power outages. Transformers that use photo-cells and have an adjustable on-time (typically 2,4,6 or 8 hours) should also be avoided as the on-time would need adjusting thought the year as it gets darker later in summer. In Florida the lights will typically be on for 6 or 7 hours in winter and 4 hours in summer. Afternoon thunderstorms can also trigger the night cycle when the sky goes dark which may leave the lights on after the storm and then off later at night. The best transformer will turn the lights on at dusk and turn them off at a pre-set time, such as midnight. This will require no adjustment throughout the year. A battery backup keeps the timer (for the turn off time) on track through power interruptions. Nightscapers only uses this type of transformer, which incidentally is so tough, it's guaranteed for life.
It is very important is to use a multi-tap or multi-voltage transformer for your system. This allows the designer and installer to ensure that each and every fixture gets the proper volts needed for the long life of the system bulbs. A lower cost single tap transformer (that only puts out 12V) will almost certainly not allow the correct working voltage for every fixture and the system will suffer early bulb failure.
Connections — The single most important installation detail
Besides burned out bulbs, the cause of most low voltage landscape lighting system failures is the wire connections that are buried in the ground. Most installers use wire-nuts or alligator type connectors for all system connections. While the impregnated wire-nut connectors do perform well to connect a fixture to the main wire, they do not hold up for the more demanding tee and branch connections where several wires are connected together and much more power is flowing. The corrosive Florida soil works its way into the tee connections more easily and starts to corrode the copper wiring. It's only a matter of time before the connection fails and the lights go out — see the photo on the right as an example of what can happen after only a few months. The repair task can be difficult since the connections are buried underground, so finding the problem can be time consuming and disruptive to your landscaping. The alligator clamp on connectors are even worse than the wire-nuts in allowing wire corrosion - they are not impregnated with a sealer so they offer no protection from the soil, and hence they should be avoided at all costs.
Nightscapers solders all tee and branch connections for durability. The solder protects the wire from the corrosion and ensures the electrical connection remains strong. The joint is then sealed to keep the water out.. This process takes considerably longer than using a wire-nut, but ensures your system will be trouble free for many years.
Low (12V) Voltage Systems vs. High (120V) Voltage Systems
Low-voltage landscape lighting systems using modern technology are displacing the traditional high-voltage landscape lighting systems in most residential and commercial applications. The primary reasons for this change are:
1. Low-voltage systems provide superior light control through a wide choice of light fixtures and lenses.
2. Low-voltage systems offer significantly lower operating costs as less light is wasted on the sky.
3. Low-voltage systems do not suffer from moisture ingress problems that can plague high-voltage systems causing shutdowns.
4. Low-voltage systems are inherently safer requiring a much less invasive installation which also results in substantial savings in cost.
There are no situations that a low-voltage system cannot handle. They do have the necessary power to successfully compete with high-voltage systems and typically accomplish the task using 1/3rd less electricity and at a much lower installation cost. LED lighting systems use 75% less energy.
Are there any disadvantages to using low-voltage systems?
As long as you find a company you can trust to design your system correctly and install it properly there are no disadvantages to using low-voltage lighting systems. Nightscapers' only business is lighting so all of our designers and installers have received up-to-date manufacturer training ensuring we do it right the first time.
What about solar powered light fixtures?
While simple to install, solar powered light fixtures are typically seriously under powered. The solar units typically output a fraction of the light that a low voltage lighting system will provide. The durability of the solar units is also poor as the batteries soon wear out due to the constant charge and discharge cycle. Also, overcast days will not allow the batteries to charge enough to power the units for the night.
What about LED lights?
Until recently LED lights were not practical. The color was a bluish white and the fixtures were cost prohibitive. Recent advances have made LED lights the choice for many future installations. The color is now available comparable to halogen and costs have dropped significantly. LED lights will last for 40,000+ hours compared to 5,000 to 10,0000 maximum for halogen and use 25% of the energy. A lifetime warranty is available.
What are the pros and cons of LED lights?
Less expensive installation (you can use cheaper and less wire, less voltage means less transformer requirement)
Lower operational cost (75% less energy use for equivalent lighting)
No bulb changing for 40,000 hours+ (if a fixture becomes faulty or the light goes out it is replaced at no charge-except for labor)
Less flexibility with changes (each fixture is a specific wattage and beam spread so in order to make a change you need a new fixture not a new bulb)
When a light burns out the fixture will need to be replaced and eventually in 15 to 20 years all fixtures will need to be replaced (with halogen the fixtures are warranted for life and you simply change bulbs as necessary)
Slightly less flexibility in beam spread and wattage offerings
What about the landscape lighting kits I see at home improvement stores?
Kits are available to allow the home owner to install a landscape lighting system. These systems however are very different from a professional landscape lighting system. The installation manuals of these systems never mention voltage drop calculations and hence most systems are installed with no regard to the problem. As a result users can expect low voltage at most of the fixtures which will shorten bulb life and provide a yellow light at much less intensity that the rated output. The instructions conveniently also forget to offer suggestions on how to get that wire under the driveway or sidewalk. (Simply "jetting" under such obstacles with a hose and pipe is not recommended as this may leave the driveway support weakened and subject to settling.) The fixtures attach to the cable using alligator type clips which work well for a short period, but over time the connection will corrode and result in fixture failure. The fixtures themselves are always lower quality and often have fatal design flaws including allowing water build-up on the lens.
Finding a competent contractor
Low Voltage Landscape Lighting systems have many significant advantages over high voltage (120 Volt) systems, but they must be designed and installed properly. Nightscapers' only business is lighting so all of our designers and installers have received up-to-date manufacturer training so we do it right the and install your system, ask them the following questions. Always confirm the installer is a "licensed contractor".
Q: Have your staff recently received training specifically for low voltage lighting design and installation?
A: Only a training course specifically aimed at low voltage lighting design and installation will ensure your designer and installer understands the necessary procedures to create a properly designed, durable system. New techniques are ensuring a longer trouble free operating life for your system so recent training is a must.
Q: What are the types of bulbs used in your system?
A: You are looking for Halogen or Xenon bulbs – incandescent bulbs will have a limited lifespan and will require frequent replacements. LED bulbs are now practical for many installations.
Q: What is voltage drop?
A: When power runs through a cable a voltage drop occurs. The higher the current, the larger the voltage drop. Even over a relatively short run the cable can cause a several volt drop – which means the bulb will not get the full voltage it needs to operate correctly. The designer must plan and compensate for voltage drop.
Q: What is the range of voltage that is acceptable for the bulbs in your system?
A: 10.8 volts to 12.2 volts is the acceptable range for Halogen and Xenon bulbs. Nightscapers uses 11 volts as the low cut-off to ensure the bulb always has sufficient voltage to operate correctly. For LED systems the range can be greater.
Q: What happens if the bulbs don't get the correct voltage?
A: For halogen and xenon bulbs the result is drastically reduced bulb life. LED lights may not operate at all.
Q: How do you address voltage drop?
A: The designer must run calculations to determine what the voltage drop will be in all of the cable runs and compensate for the drop using a multi-tap transformer. Voltages must be balanced within a cable run by using center fed tee (or "T") cabling. During the installation measurements must be taken with an accurate voltmeter to ensure the correct voltage at each fixture.
Q: What sort of connections do you use?
A: For durability you should insist on soldered connections for all tees and branches. The use of wire nuts or alligator type connectors is not recommended for tee or branch connections due to the high currents involved. However, for connecting the supply wire to the fixture, wire nuts filled with a silicone or petroleum based sealant are fine for connections of less than 50W.
Q: What grade of aluminum is used for your fixtures?
A: You are looking for marine or aviation grade aluminum. When near salt water areas brass or copper is recommended.
Q: What method is used for painting the fixtures
A: Baked-on powder-coat finish is significantly more durable than a sprayed paint finish.
Q: Will your fixtures allow any water to get trapped on the lens?
A: Fixtures should have drain holes or no lower lip to prevent or at least minimize water build-up.
Q: What material is the fixture lens made from?
A: The fixture lens should be made from soda-lime glass to minimize mineral deposit build-up and to make them easy to clean without scratching.
How can I be sure my system has been designed and installed correctly?
Insisting on adequate documentation and a simple test procedure will ensure the contractor has designed and installed your lighting system correctly. You should require your contractor to provide the following information:
· A drawing showing all fixtures and circuit connections including approximate wiring run locations.
· A Fixture list including:
· Reference number on drawing
· Manufacturer Part number
· Measured Voltage at Bulb (with all system fixtures operational)
· Circuit list and analysis including:
· Circuit Identifier
· Circuit Measured Current
· Transformer and Breaker number
· Transformer List and Analysis including:
· Transformer Manufacturer Part Number
· Transformer Identifier
· Total wattage per Breaker
These measurements must be taken to ensure any system is operating correctly so providing the information to you should be no problem for any contractor who has designed and installed the system properly. Of course if they have something to hide, they wouldn't want you to see this data. Nightscapers proudly presents this information to each and every customer.
This information will also be invaluable for maintaining the system throughout it's lifetime.
Don't worry that you may not fully understand the information - the fact that the contractor has provided it means they have taken the time to measure it. The following short test will ensure they have actually measured the values and not made them up!
Besides showing you how the system works, ask the contractor to perform the following quick tests that should only take a few minutes. Don't pay the invoice until you've seen the results!
1. Turn the system on and check that all fixtures are operating. Choose three fixtures from the list the contractor provided you. One fixture should be close to the transformer and one should be the furthest from the transformer — the other can be any random fixture.
2. Ask the contractor to measure the voltage at each of the fixtures (with the bulb for that fixture still operating.) The voltage should match the voltage shown on the fixture information sheet and it should be between 11 and 12V for halogen and xenon bulbs. To account for slight changes in the 120V supply, you can accept minor variation in voltage of no more than 0.2 of a volt, i.e. the measured voltage should be between10.8 to 12.2V for halogen and xenon bulbs or manufacturer requirement for LED systems.
3. If the voltage is not between 10.8 & 12.2V for halogen or xenon systems then the acceptance test should be halted until the problem is fixed. Once the problem is fixed choose three more random fixtures regardless of how many you tested previously. If the voltage is between 10.8 & 12.2V but noted incorrectly on the fixture information sheet request the information be corrected on the sheet.
4. Pick a couple of the circuits shown on the fixture information sheet at random and ask the contractor to measure the current for each of the chosen circuits. (This is very quick and easy to do with a clamp ammeter.) The values on the sheet should match the measured value within 0.5A.
We often get asked why we use Halogen bulbs when they seem to be a little finicky about their supply voltage. Firstly, halogen or xenon bulbs last so much longer than regular incandescent bulbs and hence the lighting system will require much less maintenance. Secondly, the light from halogen bulbs is much whiter and brighter than regular bulbs - and stays so for the life of the bulb. LED lights now offer comparable color and when appropriate can give significantly longer life than even halogen or xenon bulbs.
Why do Halogen bulbs last much longer than other bulbs?
Halogen is a type of incandescent bulb. It has a tungsten filament just like a regular incandescent bulb that you may use in your home, however the bulb is filled with halogen gas. When an incandescent bulb (one which produces light by heating a tungsten filament) operates, tungsten from the filament is evaporated into the gas of the bulb and deposited on the glass wall. The bulb "burns out" when enough tungsten has evaporated from the filament so that electricity can no longer be conducted across it. In a halogen bulb however the tungsten is recycled due to an effect know as the halogen cycle. As the bulb wall rises above 250°C the halogen cycle begins to operate. Tungsten molecules evaporated from the filament combine with the halogen vapor to form a tungsten halide. The halide no longer condenses on the hot wall of the bulb but is circulated by convection back to the region of the filament. This gives the halogen bulb a much longer life than regular incandescent bulbs and provides for a cleaner bulb wall for light to shine. It also allows the filament to run hotter and this produces a whiter more natural light.
Why is it important to run halogen bulbs at their design voltage?
For the halogen cycle to operate properly the bulb wall must be maintained above 250°C. To maintain this temperature the bulb must be driven at its design voltage. While it may be obvious that too much voltage will shorten the life of the bulb, running a halogen bulb at too little voltage has several detrimental side effects that will also lead to premature failure. Too little voltage will not run the bulb hot enough to allow the halogen cycle to operate. This will cause the tungsten to deposit on the wall of the bulb both depleting the filament and causing the bulb wall to blacken. Too little voltage also runs the filament at a lower temperature causing the light emitted to be more yellow. Practically speaking the voltage at the bulb must be maintained between 11 and 12 Volts.
If I use a 12V transformer, won't the voltage at the bulb be 12V?
Unfortunately the answer is no! The wires use to connect the fixtures to the transformer have a natural "resistance" to the power flowing to the bulb. This resistance causes the voltage to "drop" across the wire. It is not uncommon for the voltage to drop 2 or 3 Volts along runs from the transformer to the light fixture, so the bulb only gets 9 or 10 Volts. If this voltage drop is not compensated for, the bulb life and light output of the fixture will be compromised. Professional landscape designers will keep the voltage at all the fixtures within the exacting specifications for optimum performance and bulb life. The system wiring must be installed using complex calculations to determine the best way to run the wiring. While first instinct would be to run the wire from the transformer to the nearest light and then onto the furthest light, this will almost guarantee the near light is too bright and the far light will be too dim. (This also guarantees a short bulb life for both of these fixtures and many of the fixtures in between.) The fixtures must be wired in a tee where the power runs to the lights in the middle first. This technique requires the use of much more cable but with careful calculations and measurements the system can be guaranteed to have the design voltage at each and every fixture.