If you’re weighing landscape lighting against the fear of a bigger power bill, the short answer is: it barely moves the needle. A typical low-voltage LED landscape lighting system adds somewhere between $2 and $7 a month to your electric bill — often less than what a single incandescent porch light costs to run all night.

Here’s the real landscape lighting electricity cost, broken down by system size, plus what actually drives the number up or down.

How Much Electricity Does Landscape Lighting Actually Use?

Modern landscape lighting runs on low-voltage LED fixtures, and LEDs are dramatically more efficient than the fixtures most homeowners picture when they think “outdoor lighting.” A typical LED path or step light draws just 1 to 4 watts. Uplights aimed at trees or architectural features use more — usually 5 to 20 watts, depending on the height and canopy size of what’s being lit. Even a fully loaded system with 25-30 fixtures rarely pulls more than 200-250 watts total, roughly the same draw as a single window air conditioner running for a few minutes.

A professionally sized system like this uses a correctly rated transformer to avoid voltage drop and wasted energy across every fixture.

How Much Does It Cost to Run Landscape Lighting? (By System Size)

Electricity in Indiana and Illinois runs around 18¢ per kilowatt-hour on average. Assuming a system runs about 5 hours a night — dusk to around 11 p.m., which is typical with a timer or photocell — here’s what that works out to:

These numbers assume a correctly sized, low-voltage LED system — the kind a professional designs from the start. Every figure above is based on 5 hours of nightly runtime; a photocell that automatically adjusts for shifting sunset times through the year brings the real-world cost down even further.

LED Landscape Lighting Energy Efficiency vs. Older Systems

The bigger cost swings come from what’s driving the fixtures, not the fixtures themselves. Older halogen landscape lighting fixtures typically use 20 to 50 watts each — five to ten times what an equivalent LED fixture draws — and LED lighting uses at least 75% less energy than halogen for the same brightness. That’s the core of low-voltage lighting energy cost: it’s driven almost entirely by wattage and runtime, not by the number of fixtures in the ground. A homeowner with an aging halogen system can often add fixtures and still lower their monthly cost simply by converting to a professionally designed low-voltage LED system. Line-voltage (120V) outdoor lighting, which runs on standard household current instead of a stepped-down transformer, tends to cost more to run and carries higher installation and code requirements.

Keeping Costs Low Without Cutting Fixtures

• Use a timer or photocell instead of manual switches, so the system only runs during actual darkness hours instead of running by habit.
• Choose fixture wattage based on what’s actually being lit — a small path light doesn’t need a 20-watt bulb, and a mature oak canopy needs more than a 5-watt spotlight can deliver.
• Have your transformer sized correctly. An undersized or overloaded transformer causes voltage drop, which makes fixtures run dimmer and less efficiently across a run.
• Convert old halogen or incandescent landscape fixtures to LED, which is often the single biggest cost reduction available without changing the design at all.

If you’re wondering about the cost to run outdoor lights all night versus on a timer, the difference comes down almost entirely to hours, not wattage. A timer that shuts the system off at 11 p.m. instead of letting it run until sunrise can cut runtime — and cost — by 40% or more without changing a single fixture.

What a Professional Design Gets Right That DIY Setups Often Miss

The cost numbers above assume a correctly designed system, and that assumption is doing a lot of work. A poorly planned system, whether it’s a DIY kit or an older install that was never dialed in, often ends up costing more to run than a professionally designed one, even with fewer fixtures. Here’s where that gap usually comes from:

• Wire gauge and run length. A wire that’s too thin for its run length causes voltage drop, which makes fixtures at the end of a run look dimmer than the ones near the transformer. The common fix homeowners reach for — swapping in brighter, higher-wattage bulbs to compensate — increases the electric bill without actually solving the underlying wiring problem.
• Transformer voltage taps. Most transformers have multiple output taps (commonly 12V, 13V, 14V, and 15V) specifically to compensate for different run lengths across a property. A professional install dials these in during a nighttime walkthrough, so every fixture gets the voltage it needs; a DIY setup usually leaves the transformer on a single default tap for the whole system.
• Matching wattage to the object, not the general area. Over-lighting — using more wattage than a feature actually needs — is one of the most common DIY mistakes, and it adds real cost without adding real visual impact. A 20-watt fixture aimed at a small shrub burns the same electricity whether it looks good or not.
• Photocell calibration by season. A flat timer set once in the summer will run extra, wasted hours once the sun starts setting earlier in the fall and winter. A properly calibrated photocell adjusts automatically, so the system only runs during actual darkness year-round.
• Documented load headroom. A professional install leaves a record of exactly how much capacity is left on the transformer, so if you add fixtures later, you’re not guessing whether the system can handle it or unknowingly overloading it.

When to Call a Professional

Most of the cost differences above come down to design decisions made before a single fixture goes in the ground — wattage per fixture, transformer sizing, timer settings, and wire gauge all affect both light quality and the electric bill. A professional installation accounts for all of it upfront, so homeowners aren’t guessing at fixture counts or discovering voltage drop problems after the fact.

If you’re not sure whether your current system, or a system you’re planning, is sized efficiently, a quick walkthrough with a lighting designer can usually tell you in minutes. Contact us