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How much does it cost to run Christmas lights?

By Nazrul Islam. Updated October 11, 2026.

How to calculate the cost of Christmas lights

Lights, inflatables and projectors all follow one formula:

Cost = watts ÷ 1,000 × hours × price per kWh

For a season, multiply by the nights too. This guide assumes 6 hours a night for 40 nights (240 hours) and 18 cents per kWh, close to the 18.2-cent 2026 U.S. average residential price that EIA projects.

Example: a 40 W incandescent mini strand uses 40 ÷ 1,000 × 240 = 9.6 kWh a season. At $0.18, that is $1.73.

How do I find the watts on the box?

Check the box, the tag near the plug or the spec sheet. You will see one of three things:

• Watts: use it directly.
• Amps only: multiply amps by 120 volts. A strand rated 0.08 A draws about 0.08 × 120 = 9.6 W.
• Watts per bulb: multiply by the bulb count. Twenty-five 7 W C9 bulbs draw 175 W.

The label also lists the maximum strands you can connect end to end. Treat it as a hard limit.

How many watts do Christmas lights use?

Figures come from spec sheets for specific listed products. Check your own strand’s label.

The LED mini strand uses 76% less power than the incandescent mini. The LED C9 strands use 89% to 99% less than an incandescent C9. ENERGY STAR says certified decorative light strings use about 92% less energy than incandescent strings. Its specification, which dates from 2011, caps certified strings at 0.2 W per bulb. ENERGY STAR-labeled strings can be hard to find in stores now.

Incandescent C7 and C9 strands are the real energy hogs: one C9 strand draws as much as about 18 LED mini strands.

Cost per strand by night, season and electricity rate

Your rate is on your electric bill: divide the total bill by total kWh. Season columns assume 6 hours a night for 40 nights.

How much do inflatables and projectors cost to run?

Inflatables run a fan the whole time they are up, so they are often the biggest loads in a yard. Listed ratings for two laser projectors and four Home Depot inflatables:

These ratings are amps × 120 volts, likely maximums; actual draw may be lower. Size alone does not predict power: the 12 ft. cactus is rated far below the 6 ft. animated scene. Motors and built-in lights add the most.

Gemmy’s instructions say to plug outdoor inflatables into a covered, weatherproof GFCI outlet and not to use an extension cord.

What does a whole-house Christmas display cost?

Switching the strands to LED cuts the large display’s season bill by about $106 at 18 cents. In the large LED display, the three inflatables use more than half the power.

How many strands can you plug into one outlet or circuit?

Two limits apply. Follow whichever is lower.

1. The strand’s own limit. The first strand’s wire carries current for every strand plugged into it, so exceeding the label’s “max connected sets” can overheat it. Even if the label allows 5, CPSC advises connecting no more than three incandescent sets.

2. The circuit’s limit. A standard 15-amp, 120-volt circuit can supply 15 × 120 = 1,800 W. The National Electrical Code treats a load that runs 3 hours or more as continuous and limits it to 80% of the breaker rating: 1,440 W on a 15-amp circuit. Holiday lights running all evening count.

Everything else on the circuit, from porch lights to a garage freezer, shares that 1,440 W. The large incandescent display above needs at least three separate circuits. With LEDs, the end-to-end limit usually matters more than the circuit.

If a breaker trips, move part of the load to another circuit instead of resetting it repeatedly.

Christmas light safety: UL listing, outdoor rating and GFCI

• Buy listed lights. The strands we checked are listed by a testing lab; look for UL, ETL or CSA on the box.
• Match indoor and outdoor ratings. ESFI says all outdoor cords and decorations should be marked for outdoor use.
• Use GFCI protection outside. ESFI recommends plugging outdoor decorations into GFCI-protected outlets. If yours has none, a portable outdoor GFCI needs no installation.
• Follow the product’s cord instructions. Some inflatables, such as Gemmy’s, say not to use an extension cord. Otherwise, use outdoor-rated extension cords sized for the load, and keep plugs out of snow and standing water.
• Use ladders carefully. Falls are about half of decorating injuries, per the CPSC. Set the ladder on firm, level ground and have someone steady it.
• Inspect before hanging. Throw out strands with cracked sockets, frayed wire or loose connections.
• Keep a real tree watered every day; a dry tree burns much faster.
• Turn decorations off when you leave home or go to bed, as ESFI advises.

The risks are real. The CPSC estimates about 160 holiday decorating injuries a day during the season. About 14,900 people went to emergency rooms in the 2023 holiday season (Nov. 2022–Jan. 2023). NFPA reports that U.S. fire departments responded to about 155 home fires a year involving Christmas trees from 2018 to 2022. Electrical distribution or lighting equipment was involved in 41% of them.

Do timers and smart plugs save money on Christmas lights?

Yes, mostly by preventing all-night burning. Dusk to dawn in December can run about 14 hours. At 18 cents per kWh over 40 nights:

A timer also reduces the fire risk of lights left on while everyone sleeps. Outside, use an outdoor-rated timer or smart plug rated for your load.

Is it worth replacing incandescent Christmas lights with LED?

Payback = price of the new LED strand ÷ yearly savings.

If an LED C9 strand costs $25, it pays for itself in about 3.4 seasons at 18 cents. If an LED mini strand costs $10, it takes about 7.6 seasons. At 30 cents, those drop to about 2 and 4.6 seasons. Plug in what you actually pay.

Rule of thumb: replace big C7 and C9 incandescents first, and swap minis as they burn out. ENERGY STAR says certified LED strings can last up to 10 times longer, carry at least a three-year warranty and run cool to the touch, which reduces fire risk.

A space heater on the same circuit shares that 1,440 W budget. For winter outage backup, see power station vs. generator.

Quick answers

Do Christmas lights raise your electric bill much? An all-LED display of a few dozen strands, without inflatables, adds roughly $5 to $20 a season at 18 cents per kWh. Large incandescent displays with inflatables can add $100 or more.

How many light strands can I connect together? Follow the maximum on the box or tag. The LED strands above allow 21 to 90 end to end. For incandescent sets, CPSC advises no more than three, even if the label allows 5.

How many watts is a C9 Christmas light bulb? A traditional incandescent C9 bulb is 7 W. LED C9 strands here draw 2.4 W to 20 W per 25 bulbs.

Do Christmas inflatables use a lot of electricity? The ones checked here are rated 60 W to 432 W, or about $2.59 to $18.66 a season at 18 cents.