Outdoor Lighting: 12 volt vs 120 volt


16 Sep Outdoor Lighting: 12 volt vs 120 volt

When it comes to picking the right outdoor light system it is important to know all the facts. In the past there were definitely pros and cons to either the 12 volt or 120 volt option, but now the decision is, in our opinion, a no-brainer. Before LED we may have advised clients with larger landscapes to use 120 volt, but now we would recommend a 12 volt system for 99% of landscape lighting jobs.

12v_2w_chip_on_board_cool_white_led_mr11_light_bulb__87585-1397084605-220-220Here’s why…

A 12 volt outdoor light system is much safer than the higher voltage alternative, and with LED technology the issue of voltage drop is virtually eliminated. When it comes to 12 volt systems, you can rely on the fact that they are less expensive, easier to install, and offer more fixture selections. Residential properties should always use 12 volt system, and the majority of commercial builds are making the smart decision to transition to implement the low voltage alternative.

Less expensive, easier install, and more designer options

The materials needed to install a 12 volt system are already less expensive than the 120 volt option. When you combine the savings on materials, you benefit even greater by reducing your installation costs. A 12 volt system is very safe and doesn’t need the amount of precautions that a 120 volt system requires. With the low voltage option, you could potentially install everything yourself, saving a ton in labor costs. Even if you have an electrician install your system, 12 volt circuits do not require intensive installation effort. The wires can be run along the top of your soil and only covered with ground cover or bark for aesthetics; there is no fear of accidentally cutting a line and causing serious injury. A 120 volt system is another story. A high voltage system does have codes that mandate the wires be at least a foot and half deep below ground, which means you are paying for the materials and increased labor costs for the trenches that are required. Finally, 12 volt light fixtures come in a variety of designs and finishes, whereas 120 volt options are extremely sturdy but limited. 120 volt fixtures are built to be abused by the general public, while 12 volt fixtures are designed to last, but could be more easily damaged by vandals. When it comes to our recommendation, we would encourage residential and commercial clients to go with 12 volt systems.

Common Myths

  1. “To avoid voltage drop, I have to use 120 volt.” For a halogen system this still stands true, but LED now offers the same light output with a massive reduction in energy use. For laymen, voltage drop can be calculated by knowing the size of the wire, the amount of watts being drawn on each circuit, and the length of the run being installed. Previously, halogen systems would draw anywhere between 25 to 50 watts of energy per fixture depending on light output. So with a 1500 watt commercial grade transformer each line of 300 watts could only support 5 to 6 fixtures depending on the length of the run, even if you used a 10 gage wire. Now consider that same system using LED. The math completely changes the voltage drop issue. Each fixture would draw between 3 to 6 watts with the same light output as their halogen challengers. You could potentially  have 50 fixtures on the same run without encountering a voltage drop issue.
  2. “I have to use 120 volt because I have really long runs, 12 volt can’t handle it.” This myth is along the same lines as the first one. Remember, voltage drop is determined by 3 factors: the size of the wire, the wattage draw, and the length of the run. The answer to this perceived issue is the same – LED! Honestly, you could have a 500 foot long run and if you used a larger wire, let’s say 8 or 10 gage, you could run over 30 fixtures without a problem. The resolution is truly found in the power saving technology of LED. When you can have 50 watts of light output while only drawing 6 watts of energy, 12 volt systems become a better alternative.
  3. “My clients don’t want to spend $200 on a transformer in order to install a 12 volt system.” Do not let this line fool you! Unless your commercial project already has trenches being dug all over the place, and you’re still in the construction phase of your project, the labor costs will far outweigh the one time purchase of a transformer. If this is a residential project considering their voltage options, do not pay for your landscape to be dug up and then replaced.

Now for the 1%

After all that, we will concede that there is a time when a hardwired, 120 volt system would be a better selection. For commercial projects that are just beginning, the cost of labor will be a factor based on other utilities being installed, so the trenches and conduits for the electrical shouldn’t be a large hindrance. Also, if some of the fixtures being selected are for major parking lots and require a higher voltage, 120 volt is encouraged. Since you can still run LED on 120 volt system, the project can still save money through lower energy use, and can use extremely durable fixtures for their project. Now, if your commercial project doesn’t encounter an exuberant amount of foot traffic, fixture durability might not be an issue, but it is good to know the heavy duty fixtures are available. So while we would love to say we recommend 12 volt 100% of the time, there still is the 1% to consider.

Honestly, the value of 120 volt is truly just perceived. Voltage drop is no longer an issue to deter commercial or residential projects from 12 volt systems. Don’t let your project fall victim to a force of habit. Make sure you properly vet the professionals quoting your project, and always go with 12 volt for your landscape lighting needs – unless you are truly part of the 1%.  

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