View Full Version : Energy savings using low voltage lighting

Dreams To Designs
03-17-2006, 06:29 PM
I just read an excellent article on the Cast Lighting web site about the advantages of using low voltage lighting over standard 120 volt lighting and ways to improve the efficiency of our low voltage lighting installations. The principles apply whether using a hub or inline system and the cost savings for the client can be substantial due to using less energy.


03-17-2006, 11:04 PM
please tell more about what you learned

Dreams To Designs
03-18-2006, 07:25 AM

You can check it out on Cast's website. They have many articles for installation design and tips and tricks. http://www.cast-lighting.com/art-energy-cons-80.html

I make a habit out of checking information on the major manufacturers websites regularly, and they all have excellent information to make us and the industry better.


03-18-2006, 09:02 AM
thank you for the info

03-18-2006, 09:25 AM
Great info Kirk. Thanks for the heads up.

03-18-2006, 10:47 AM
great article. Another great sales point. Especially if your a few hundred more than a competitor.

I thought about comparing energy savings like they do vehicals and the total cost of ownership of a system but I wouldnt wanna confuse a customer. Anyone have a article about the energy savings over high voltage? There is an electrician here who puts 500 watt halogen spreaders in peoples yards... I can just imagine looking out one of the windows from inside thier homes " OMG MY EYES IM BLIND!"

03-18-2006, 11:23 AM
Billy, here is a way to point that out. A 500 watt lamp is using 4.16 amps at 120 volts. You could install a 600 watt transformer which, if fully loaded would use 5 amps. Of course you would not fully load a transformer, so you could install a complete lighting system that would use the same if not less power than 1 of his 500 watt fixtures!! I have installed many systems with one 600 watt transformer.

03-18-2006, 11:49 AM
I tried to edit the last post but was too late. Here is a calculation to use.

Low voltage 35 watt fmw lamp.
Annual operation: 6 hours daily
35 watts times 2,190 hours times .10 (use your local cost here) cents per kilowatt divided by 1000, equals $7.66 annual cost of operation.

Line voltage 500 watt lamp.
Annual operation: 6 hours daily
500 watts times 2,190 hours times .10 (use your local cost here) cents per kilowatt divided by 1000, equals $109.50 annual cost of operation.

I would say that you might be able to save the client a few bucks here.

03-20-2006, 12:02 PM
Thanks Kirk for drawing attention to the article. Paul, in comparing 120v to 12v, we need to be fair. As you know, we would never replace a single 500w flood with a single 35w fixture. We would always use a number of fixtures in an intelligent design.

In fact, it may be that we propose a design with equal or more wattage than the original 120V scheme. Energy conservation is only one of our goals.

And, for those not clear on the subject. Watts at 12v is equivalent to watts at 120v. In other words, a 20w 120v lamp consumes the same amount of energy as a 20w 12v lamp. The big difference is that the 12v lamp produces far greater light output (lumens/watt) so you can use smaller wattage 12v lamps to produce the same amount of light as higher wattage 120v lamps.

Dreams To Designs
03-20-2006, 12:45 PM
Other than lighting a home to resemble a store front and occasionally needing that much lamp to light a sign, I have only seen the need for 500W fixtures as yard or driveway lights on motion sensors or elevated for a horse shoe pit or volleyball court. The use of 50 watt, flagpole, or 35 watt lamps in a bullet, flood or well light fixture is usually more than enough to uplight anything well, sometimes used in multiples.

Not only should we be saving energy compared to 120V, but we should be saving dark skies. Less is definitely more with landscape lighting and that should benefit the client as well.

Paul, you used 6 hours daily, is that an average of what you usually set a system up for? I have done a few that were dusk till dawn, but I prefer dusk till midnight.


03-20-2006, 05:08 PM

As noted in the article, setting timings from dusk till dawn is only necessary for fixtures used for security and safety. Architectural and other landscape lighting can be set from dusk till everyone is asleep – on separate transformers, of course.

03-21-2006, 11:51 PM
Kirk, I set mine to go off at midnight. I use 6 hours as a yearly average. During the winter months, it might be more like 7 hours.

Steve, since I did'nt know what the 500 watt fixture was being used for, I just used the numbers that Billy provided to demonstrate the formula for calculating the cost of electricity. I can do a complete lighting project with 500 watts, you can't do a complete lighting system with one 500 watt fixture.

I probably should have explained myself a little better. Sometimes I'm just in a hurry. My apologies to all. I will try to be more specific in the future.

Dreams To Designs
03-22-2006, 07:34 AM
Paul, unfortunately I saw a home yesterday that was light by A 500 watt quartz floodlight in the yard. It's a shame what some people think is good lighting. Your calculations made sense to me, that is why I was confirming the average and figured you were using a timer to turn off the lighting at midnight.


03-22-2006, 08:55 AM
we got several homes around here with that. I do have flood lights on my home because we live in the country but i just switch them on as needed.

Makes me think of 1 house in town. nice older home. There is at least 7 huge halogen lights outside this home and its brighter at night then it is during the day time. I will have to take a picture of it lol. I couldnt imagine being a guest and walking out the front door and having the feeling a train is coming at me.

I want to take a picture of a person walking out of a home like this shielding thier eyes and then a group of people leaving a properly lit home

03-22-2006, 01:59 PM
That would be a great photo!

Paul, I didn't mean to imply that you don't know your stuff. Of course, you are a master and we can all learn from you.

03-22-2006, 07:14 PM
Please, I am not a master by far. I know I have a great deal to learn from people like you, Steve and people like Mike Gambino and even Joe Masciotti. I do truly love what I do though and can't wait to go to work in the morning and get home a whatever time that might be.