What Does it Cost to Operate a Landscape Lighting System?

Over the years a lot of homeowners have asked us how much their monthly electricity bill would increase after their landscape lighting system was installed. The short answer and the good news is not very much!

Most recently some townhome owners in Denver needed to share a low voltage quartz halogen landscape lighting system to illuminate their front entrances. The as-built configuration of the townhomes dictated that only one of the townhomes would have the low voltage transformer installed – and subsequently would have to provide all of the power for the entire lighting system. The respective homeowners agreed to split the annual electricity bill/usage for the system and asked me to compute how much that would be.

For this system, there were a total of two uplights (well lights at 35W each) and four path lights for the walkways (at 20W each) – for a total energy usage of 150W. For safety and security, the homeowners wanted the lights to be on from dusk to dawn throughout the year.

By accessing the U.S. Naval Observatory website and doing some computations, I was able to determine that there are a total of 4,306.29 hours of darkness for the entire year in Denver, Colorado. By multiplying 150W times 4,306.29 hours you get 645,943.5 watt-hours or 645.9 kWH. The average cost per kilowatt-hour in Denver is projected to be 11.3 cents through the year. By multiplying $.113/kW-H times 645.9kWH, you end up with a total operating cost of $72.99 per year, or $6.08 per month or $.20 per night. Most police departments will tell you that this is a small price to pay to enhance your home’s safety and security every night of the year.

Ken-Caryl House Lighting

The house on the left (also using a low voltage quartz halogen lighting system) has a total of 8 uplights (35W each) and 3 path lights (20W) each – for a total of 340W. Dusk to dawn operation costs $165.44 per year or $13.78 per month or $.45 per night.

If this same low voltage quartz halogen system is replaced by a low voltage LED lighting system in the future, the total power requirement would only be 80.7W and would result in annual energy costs of $39.26 per year or $3.27 per month or $.11 per night Рa 76-percent energy savings over the quartz halogen system.

So in other words LEDs are the future but even with a low voltage quartz halogen lighting system, you’re still saving money with operating your outdoor lighting in comparison to line voltage lighting.

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