A well-designed LED landscape lighting system usually costs a few dollars a month to run, often less than a streaming subscription. The exact number depends on four things you can look up in a few minutes: how many fixtures you have, their wattage, how long they run, and what you actually pay per kilowatt-hour. This guide walks through the math, gives you a calculator to test your own system, and shows where the real savings are.
How a low-voltage system uses power
Most professional landscape lighting runs at low voltage, typically 12 volts. Household power at 120 volts feeds a transformer, which steps it down and sends it through buried cable to each fixture. The fixtures draw power according to their wattage, and the transformer loses a little along the way as heat.
The core relationship is simple: more watts, running for more hours, use more energy. What surprises people is how much the type of fixture matters compared with the number of fixtures.
Take two homes with 20 lights each. One uses 5-watt LEDs, so the whole system draws 100 watts. The other still has 20-watt halogen lamps and draws 400 watts. Same fixture count, four times the electricity. That is why fixture count alone tells you very little about operating cost.
The four numbers that set your cost
Fixture count
A modest front yard might use 8 to 15 fixtures. A property with architecture, mature trees, paths, a pool and outdoor living areas can reach 30 to 40 or more.
Watts per fixture
Modern LED landscape fixtures typically draw about 2 to 12 watts. Older halogen lamps commonly draw 20, 35 or even 50 watts each.
Hours per night
Sunset to 11 p.m. is roughly five or six hours. Dusk to dawn can run 10 to 13 hours depending on the season.
Your real rate
Billed in kilowatt-hours (kWh). Use your all-in effective rate, not an advertised energy charge. More on that below.
Operating days matter too. Front-entry and path lights usually run every night, while patio or entertaining zones might only run eight or ten nights a month.
How to calculate it yourself
You only need four steps:
- Total wattage. Number of fixtures × watts per fixture.
- Nightly energy. Total watts × hours per night ÷ 1,000 = kWh per night.
- Monthly energy. Nightly kWh × operating days.
- Monthly cost. Monthly kWh × your rate per kWh.
Worked example
A system with 20 fixtures at 5 watts, running 6 hours a night, 30 nights a month, at $0.16 per kWh:
- 20 × 5 = 100 watts
- 100 × 6 ÷ 1,000 = 0.60 kWh per night
- 0.60 × 30 = 18 kWh per month
- 18 × $0.16 = $2.88 per month, or about $34.56 per year
For a complete outdoor lighting system, that is a small line on the bill.
Energy cost calculator
Enter your own fixture count, average wattage, schedule and rate to see wattage, nightly and monthly kWh, and monthly and yearly cost. Run it twice to compare a halogen system with an LED version, or a dusk-to-dawn schedule with a sunset-to-midnight one.
The result is a planning estimate, not a utility bill or an electrical audit. Transformer efficiency, dimming, voltage drop and your billing structure will move the real number a little in either direction.
Getting accurate inputs
- Count every fixture that actually runs. Path lights, uplights, downlights, step and wall lights, patio fixtures and tree-mounted fixtures. Leave out anything disconnected.
- Find a realistic average wattage. Check fixture labels, lamp packaging, installation records or spec sheets. With mixed wattages, total them and divide. Ten 4 W path lights, six 6 W uplights and four 9 W tree lights total 40 + 36 + 36 = 112 watts across 20 fixtures, so the average is 5.6 W.
- Use your actual schedule. If your timer follows sunset, hours change through the year. Run the calculator once for a short summer night and once for a long winter night, then average them.
- Enter operating days per zone. If zones run on different schedules, calculate each separately and add them up.
- Use the effective rate. Divide the total of your bill (energy plus delivery charges, before taxes if you prefer) by the kWh used that month.
Texas electricity rates
Much of the Houston area, including many homes around Spring and Klein, is in a deregulated market. You choose a retail electricity provider and plan, and the poles and wires are run by a separate delivery utility. Your bill usually combines the retailer's energy charge with pass-through delivery charges, sometimes plus a base fee or usage credits.
That means the cents-per-kWh figure in a plan's headline is often not what you really pay. Two better sources:
- The Electricity Facts Label (EFL) for your plan lists an average price per kWh at several usage levels, with delivery charges included. Use the figure nearest your typical monthly usage.
- Your bill. Total charges divided by total kWh gives your all-in effective rate for that month.
Some homes in the area are served by a municipal utility or electric cooperative instead and are not part of the retail choice market. The same advice applies: use the effective rate from your bill.
Example costs and LED vs halogen
These examples assume $0.16 per kWh and 30 operating nights a month.
| System | Fixtures | Watts each | Hours nightly | Monthly kWh | Est. monthly cost |
|---|---|---|---|---|---|
| Small | 10 | 4 W | 5 | 6 | $0.96 |
| Medium | 20 | 5 W | 6 | 18 | $2.88 |
| Large | 40 | 7 W | 8 | 67.2 | $10.75 |
Even the large system stays affordable because it is LED. Put 20-watt halogen lamps in those same 40 fixtures and the monthly cost climbs to roughly $30.72. Wattage usually matters more than fixture count.
LED vs halogen at a glance
| Feature | LED | Halogen |
|---|---|---|
| Typical fixture wattage | About 2–12 W | About 20–50 W |
| Energy use | Low | High |
| Heat at the fixture | Relatively low | High |
| Lamp life | Long, often many years | Shorter, frequent replacement |
| Dimming and control | Flexible | More limited |
| Operating cost | Usually lower | Usually higher |
Halogen can still look beautiful, but a conversion typically cuts lighting energy by around three quarters and reduces lamp changes. Our guide to converting halogen landscape lighting to LED covers what to check before you swap, and the LED savings calculator shows the payback for your system.
Transformers and controls
Does the transformer add to the bill?
Yes, a little. Converting 120 volts to 12 volts is not perfectly efficient, and some energy is lost as heat. Quality modern transformers lose relatively little; older, damaged or poorly matched units can lose more. Some also draw a small amount of power while idle, depending on design and controls.
Most calculators, including ours, count fixture wattage only, so your real consumption may run slightly higher than the estimate. For planning, that gap is usually small. If you want to understand capacity and losses in more depth, read how to size a landscape lighting transformer.
How controls cut energy use
Controls reduce wasted hours without making the property look dark.
- Astronomical timers follow sunset through the year, so lights do not come on too early in June or too late in December.
- Photocells switch on at dusk based on ambient light. Pair them with a timer so the system does not run all night by default.
- App scheduling lets you turn off the patio after guests leave or shorten seasonal schedules from your phone.
- Dimming decorative fixtures after midnight lowers consumption and gives a calmer look.
- Zoning is often the biggest practical win. Entry and path lights stay on later, tree and garden accents switch off when the household goes to bed.
Spring Landscape Lighting sets up smart lighting controls with zones built around how each home is actually used. You can also map your own schedule with the sunset timer planner.
Ways to lower your lighting cost
- Replace halogen with LED. The single largest reduction for older systems.
- Trim the schedule. Few homes need every accent light on until dawn.
- Zone the system. Give entries, paths, architecture and entertaining areas their own schedules.
- Dim late at night. Lower output on decorative fixtures after midnight.
- Remove redundant fixtures. One well-aimed wide beam can replace two poorly placed lights.
- Clean and re-aim. A dirty or misaimed fixture looks weak, which tempts people to install a brighter lamp. Cleaning it costs nothing.
- Fix wiring and connections. Corroded splices and voltage drop make fixtures dim and uneven.
- Revisit after the landscape grows. Gulf Coast plants grow fast, and buried fixtures waste their output.
Signs an older system is wasting energy
- Fixtures that are too hot to touch
- Frequent lamp failures
- Lights running in daylight
- Bright fixtures near the transformer and dim ones at the far end of a run
- Corroded connections or exposed wire
- A humming or overheating transformer
- No timer, or one that resets after every outage
- Halogen lamps mixed with newer LEDs
Installing higher-wattage lamps is rarely the right fix for dim lights. The wiring layout, connections, cable size or transformer settings usually need attention instead, which is the kind of work our landscape lighting repair visits handle.
Why design matters more than fixture count
Outdoor lighting is not a contest to fit the most fixtures into a yard. Too many lights create glare, flatten the texture of brick and stone, and wash out plantings. A single carefully aimed uplight can reveal a column, a wide beam can carry a live oak canopy, and a shielded path light can guide feet without shining into anyone's eyes.
The goal is not maximum brightness. It is useful, comfortable light in the right places.
When placement, beam spread and brightness are right, fewer fixtures often look better, and that lowers material cost, maintenance and electricity at the same time. If you are planning a new system, the fixture estimator gives a starting count, and a design consultation refines it.
Frequently asked questions
How much does it cost to run landscape lighting each month?
A typical LED system with 20 fixtures at 5 watts running 6 hours a night uses about 18 kWh a month, which is roughly $2.88 at $0.16 per kWh. Larger systems or longer schedules cost more, and halogen systems often cost about four times as much.
What electricity rate should I use in the Houston area?
Use your all-in effective rate. In deregulated parts of the Houston area, check the average price per kWh on your plan's Electricity Facts Label, or divide your total bill by the kWh you used. The headline energy charge alone usually understates the real cost.
Do LED landscape lights use a lot of electricity?
No. Most LED landscape fixtures draw about 2 to 12 watts, so even a 40-fixture system often uses less power than a single old halogen floodlight setup.
Does the transformer use electricity when the lights are off?
Some transformers draw a small amount of standby power depending on their design and controls. It is usually minor compared with fixture load, but older or damaged units can waste more.
Is it worth leaving landscape lights on all night?
Usually not for decorative lighting. Many homeowners keep entry and path lights on later and switch architectural and garden accents off around midnight, which saves energy and looks calmer.
How can I lower my landscape lighting bill?
Convert halogen to LED, set an astronomical timer, split the system into zones, dim decorative lights late at night, and fix any wiring or voltage drop problems before adding brighter lamps.
Spring Landscape Lighting
Landscape lighting designers serving Spring, Klein, The Woodlands and North Houston. Questions about your property? Get in touch.
