Short answer: a typical modern LED display - a handful of strings and an inflatable, on 6 hours a night - costs about $7 for the whole season, roughly $6 a month and about 20 cents a night. The same display in old incandescent bulbs costs $15-45, and a big old-bulb display can pass $100. Below is the full breakdown - per month, per night, per string - and if you want your own display’s exact figure, the free Christmas Lights Cost Calculator adds it up string by string.
How much does it cost to run Christmas lights per month?
Most people ask this by the month, because that is how the bill arrives. At 6 hours a night for 30 nights at the US average rate of about $0.17 per kWh:
| Display (30 nights) | In LED | With old bulbs |
|---|---|---|
| Small - about 5 strings | about $1 | about $6 |
| Typical house - strings, tree, an inflatable | about $6 | about $28 |
| Large - rooflines, yard, the works | about $14 | about $61 |
The season most people run - about 35 nights - lands close to those monthly figures, which is why "per month" and "per season" answers online look similar even when the writers never say which one they mean.
Do Christmas lights use a lot of electricity?
Modern LED ones: no. A 100-light LED string draws about 7 watts - about as much as a phone charger - and costs roughly a quarter to run for the entire season. The lights that earn the reputation are the old ones: an incandescent mini string draws about 40 watts, and one string of 25 big C9 bulbs draws 175 watts, twenty-five times the LED string. For scale, US holiday lights together use about 6.6 billion kWh a year - a lot for a country, pennies for a house with LEDs, and real money only for houses still running big old-bulb displays.
How much electricity do Christmas lights use? The wattage table
| Type of light | Watts | Cost for the season (6 hrs/night, 35 nights) |
|---|---|---|
| LED string, 100 lights | about 7 W | about $0.25 |
| Incandescent mini string, 100 lights | about 40 W | about $1.43 |
| Incandescent C9 string, 25 big bulbs | 175 W (7 W per bulb) | about $6.25 |
| LED C9 string, 25 bulbs | about 15 W | about $0.54 |
| Yard inflatable | about 150 W | about $5.36 (at 6 hrs - see below) |
| LED projector | about 7 W | about $0.25 |
LED vs incandescent: the worked example
Take ten strings - a roofline and a tree. In LED: 70 watts, 6 hours a night, 35 nights = 14.7 kWh = $2.50 for the season. The same ten strings in old mini incandescent: 400 watts = 84 kWh = $14.28. That 85-90% gap is the whole story of holiday-light costs: every other choice - timers, hours, nights - moves your bill by tens of percent, but the bulb choice moves it by a factor of six. It is also why two neighbours with the same-looking display can have completely different December bills.
The hidden cost nobody warns you about: inflatables
The most expensive decoration in most yards is not a light at all. An inflatable’s fan runs constantly at roughly 150-300 watts - as much as twenty LED strings - and inflatables are the one decoration people leave running around the clock. A single 200-watt inflatable left on 24 hours a day for a month costs about $21.60, more than an entire LED display. Manufacturers themselves advise against running them more than about 8 hours at a stretch. On a timer, dusk to bedtime, the same inflatable costs about $5-6 a season and lasts longer. If your December bill jumped and your strings are LED, look at the inflatable first.
How to calculate the cost yourself
One line of maths runs every figure on this page: cost = watts × hours a night × nights ÷ 1,000 × your rate per kWh. Your rate is printed on your power bill (the US average is about $0.17). Example: a 400-watt display at 6 hours for 35 nights: 400 × 6 × 35 ÷ 1,000 = 84 kWh, × $0.17 = $14.28. The catch is knowing your display’s watts - which is exactly what the calculator works out from your strings, and it shows the LED version of your display alongside.
Can your circuit handle your display?
The calculator also shows your display’s total watts, and there is one number to keep it under: a standard 15-amp circuit should carry no more than about 1,440 watts of continuous load (80% of its 1,800-watt capacity). Separately, each run of strings has its own connect limit printed on the box - roughly 3 strings end-to-end for old incandescent sets, and often 20-40 for LED sets. LED displays almost never trouble a circuit; a big C9 incandescent display genuinely can, which is one more reason the old strings are the expensive kind.
Reading this in the UK?
The same maths works in pounds - at the current Ofgem price cap of 26.32p per kWh, a typical all-LED display costs under £5 for the whole of December. We have a full UK version with pence-per-night tables here: How Much Do Christmas Lights Cost to Run in the UK? - and the calculator has a £ mode.
Three ways to cut the cost without dimming the display
Use a timer. Five hours a night instead of eight cuts running cost by about 37%, and nobody admires a roofline at 2 a.m. Replace the worst strings first. The C9s and old minis are nearly all of the wattage; swapping just those two kinds brings a mostly-old display down to nearly LED money. Tame the inflatable. Dusk-to-bedtime on a timer turns the most expensive decoration you own into a $5 one. Planning the rest of the season? The Christmas Budget Calculator plans the whole holiday spend.
Frequently asked questions
How much do Christmas lights cost per night?
A typical LED display costs about 20 cents a night (about $7 across a 35-night season). A typical old-bulb display costs about 80 cents a night, and a large incandescent display can pass $3 a night.
How much does it cost to leave Christmas lights on all night?
Roughly four times the evening-only cost, because the lights run about 24 hours instead of 6. A typical LED display left on around the clock costs about $27 a season; the strings are not the problem so much as the inflatable, whose fan also runs all night.
How much does it cost to run Christmas tree lights?
Five LED strings on a tree draw about 35 watts and cost about $1.25 for the whole season. Five old incandescent mini strings draw about 200 watts and cost about $7. The tree is rarely the expensive part of a display.
Are LED Christmas lights worth it for the electricity saving alone?
Mostly yes, and quickly: each old mini string you replace saves about $1.18 a season in running cost, and each C9 string about $5.71 - and the LED strings typically last many more seasons, so the saving repeats while the replacements stop.
Why did my January electricity bill jump so much?
The usual suspects, in order: an inflatable running 12-24 hours a day, old C9 or mini incandescent strings, then the non-light costs of December - space heaters in guest rooms, more cooking, more laundry. LED strings alone almost never explain a big jump; this guide’s calculator lets you test each suspect.
How much does a Christmas light projector cost to run?
About 25 cents for the whole season. At roughly 7 watts, a projector is one of the cheapest decorations there is - cheaper per night than the LED string next to it.