How Much Do Christmas Lights Cost to Run? LED vs Incandescent

Lighting 6 min read

By the Plug & Penny editorial team · Published 11 November 2026

A 100-bulb string of LED mini lights costs about 21¢ in the US or 30p in the UK to run for a 38-night Christmas season at six hours a night. The same string with old-style incandescent bulbs costs about $1.70 or £2.46, roughly eight times as much.

All costs use the US average of 18.16¢/kWh (EIA, August 2026) and the UK price cap unit rate of 26.32p/kWh (Ofgem, 1 October to 31 December 2026). The UK cap rate is set only until 31 December, so nights in January may be charged at a different rate.

How much power Christmas lights use

The wattage of the string decides almost everything. Here are the figures we found.

The C9 LED figure is worked out from the retailer's roofline example: 29 W for 12 strings, or about 2.4 W per string. The C9 incandescent figure is 7 W per bulb, or 175 W for 25 bulbs.

UK test results line up with this. Which? measured six LED chains of 200 and 400 bulbs in 2022. On the steady setting they cost an average of 0.13p an hour at 27.35p/kWh, which works out to about 4.8 W. A 400-bulb chain cost only slightly more than a 200-bulb one.

There is a ceiling, too. To be ENERGY STAR certified, a decorative string can use no more than 0.2 W per bulb, so a certified 100-bulb string uses 20 W at most (ENERGY STAR). The 5 W string above works out to 0.05 W per bulb, a quarter of that cap. That matches ENERGY STAR's own comparison: one 7-watt incandescent bulb uses as much electricity as 140 LEDs.

How much less do LEDs use?

Official claims range from about 70% to 92% less energy. The US Department of Energy and ENERGY STAR's Light Strings page say about 70%. An older ENERGY STAR fact sheet says about 75%. ENERGY STAR's Decorative Light Strings page says about 92%, and Which? says almost 90%.

The 70% and 75% figures appear to be older or more conservative claims; the DOE's 70% dates from 2015. With the wattages above, a 5 W LED mini string uses about 88% less than a 41 W incandescent one. Using the retailer's roofline figures, an LED C9 string (about 2.4 W) uses about 99% less than an incandescent C9 string (175 W).

How we work out the cost

The formula is simple: watts × hours ÷ 1,000 = kWh, then kWh × price = cost.

For one incandescent mini string at six hours a night: 41 W × 6 hours ÷ 1,000 = 0.246 kWh a night. Over 38 nights that is 9.348 kWh. At 18.16¢/kWh that costs $1.70 in the US; at 26.32p/kWh it costs £2.46 in the UK.

We use a 38-night season because, according to EDF, homes keep decorations up for 38 days on average. US cost guides assume anything from 34 days (Mr. Electric) to 45 days (Electric Choice). A longer season costs proportionally more.

Seasonal cost table: LED vs incandescent by hours per night

Cost for one 100-bulb mini-light string over a 38-night season.

Cost for one 25-bulb C9 string over a 38-night season.

US at 18.16¢/kWh (EIA, August 2026). UK at 26.32p/kWh (Ofgem cap, 1 October to 31 December 2026).

Most modern Christmas lights have a built-in timer that keeps them on for about 8 hours a day (Energy Saving Trust). Common timer presets are 6 hours on and 18 off, or 8 hours on and 16 off (Premier Decorations).

To cost your whole display, multiply by the number of strings. Ten LED mini strings (50 W) at six hours a night for 38 nights use 11.4 kWh: about $2.07 in the US or £3.00 in the UK. Ten incandescent mini strings (410 W) use 93.48 kWh: about $16.98 or £24.60.

Use the calculator to try your own wattage and hours. It starts with the US average price of 18.16¢/kWh. In the UK, take the kWh figure it gives and multiply by 26.32p, or use the UK tables in this article. Check the label or UL tag near the plug for your string's watts.

Christmas lights electricity cost per month

These tables show one string at six hours a night. "Per month" means 30 nights.

United States (18.16¢/kWh, EIA, August 2026)

United Kingdom (26.32p/kWh, Ofgem cap, 1 October to 31 December 2026)

The C9 figures come from a US retailer. Incandescent strings are rare in UK shops now, and we found no UK-specific wattage for them, so the 41 W mini-light figure (close to EDF's "about 40 W per 100 lights") is the best guide.

The setting you choose matters too. In the Which? test, the twinkling-flashing setting cost 0.05p an hour, against 0.13p for steady light.

Projectors and rope lights

Some display pieces use more than a basic LED string. These are manufacturer figures for specific US products, so yours may differ. Costs are for six hours a night over 38 nights.

Rope light wattage varies a lot by type, so check the label on yours. We did not find manufacturer wattages for net lights, icicle lights or inflatables. For those, read the label and enter the watts in the calculator.

What it costs in your state

US prices vary a lot by state (EIA, August 2026). Nevada was the cheapest at 12.72¢/kWh and Hawaii the most expensive at 47.18¢/kWh.

For ten LED mini strings at six hours a night for 38 nights (11.4 kWh), that is $1.45 in Nevada and $5.38 in Hawaii. Ten incandescent mini strings (93.48 kWh) cost $11.89 in Nevada and $44.10 in Hawaii. To work out your state, swap your price into the formula above.

Outdoor Christmas lights in the UK: what they cost

A typical outdoor LED set is cheap to run. A 200-LED, 40 m outdoor string rated 6 W (DecoLED) costs about 36p for a 38-night season at six hours a night (26.32p/kWh, Ofgem cap, October to December 2026). Solar sets have no mains running cost, but the panel needs daylight (Love Renovate).

For safety, Electrical Safety First says outdoor lights should carry a water-drop symbol or an IP code ending in 3 or higher. Keep plugs and transformers indoors, and use a 30mA RCD-protected socket for lights plugged in outdoors.

How to cut the cost

• Switch to LED. One LED mini string saves about $1.49 a season in the US or £2.16 in the UK compared with incandescent, at six hours a night. For C9 strings, the saving is about $7.15 or £10.36 per string.
• Use a timer. Cutting from 12 to 6 hours a night halves the cost. That saves $1.70 or £2.46 per incandescent mini string, but only about 21¢ or 30p per LED string. With no timer, the Energy Saving Trust suggests switching off at the plug, especially at bedtime.
• Try the twinkle setting. In the Which? test, it cost less than half as much as steady light.
• Check the watts before you buy. The label or UL tag near the plug lists the wattage, and a $10 plug-in watt meter can measure it (Christmas Lights, Etc). Compare bulb counts too, because they vary by string.
• Don't expect a smart plug to save on LEDs. A Wi-Fi smart plug typically draws about 1-2 W itself (Save and Upgrade), so it only pays off by cutting hours, mostly on incandescent or higher-wattage pieces.

FAQ

Is it worth replacing working incandescent lights?

It depends on how many you have. Ten incandescent mini strings cost about $16.98 (US) or £24.60 (UK) a season at six hours a night, against $2.07 or £3.00 for LED. That is a saving of about $14.91 or £21.60 a season. Compare that with the price of new LED strings.

Does the UK standing charge make lights cost more?

No. You pay the standing charge of 54.83p a day (Ofgem, 1 October to 31 December 2026) whether your lights are on or not. Only the unit rate adds to the cost.

Do more bulbs always mean a higher bill?

Not by much with LEDs. Which? found a 400-bulb chain cost only slightly more than a 200-bulb one. With incandescent mini lights, each bulb uses about 0.41 W, so the cost rises with every bulb.

Sources

1. Electric Power Monthly, Table 5.6.A (EIA)
2. Energy price cap unit rates and standing charges (Ofgem)
3. Christmas Lights Wattage (Christmas Lights, Etc)
4. Do Christmas Lights Use a Lot of Electricity? (EDF)
5. Outdoor LED string lights, 40 m, warm white, 200 LEDs, IP44 (DecoLED)
6. Ollny 200 LED 60ft Multicolor Connectable String Lights
7. Which setting on your Christmas lights is cheapest to run? (Which?)
8. Decorative Light Strings (ENERGY STAR)
9. Light Strings (ENERGY STAR)
10. ENERGY STAR Certified Decorative Light Strings At A Glance
11. How Do Holiday Lights Work? (U.S. Department of Energy)
12. The Cost of Running Holiday Lights in Every State (Mr. Electric)
13. How Much Do Christmas Lights Cost to Run? (Electric Choice)
14. Our experts' top Christmas energy saving tips (Energy Saving Trust)
15. LED Christmas Lights and Timers Save Energy (Premier Decorations)
16. Outdoor Snowflake Projector Light for Christmas (Govee)
17. Rope Light (ABBA Lighting USA)
18. Best Outdoor Christmas Lights UK (Love Renovate)
19. Electrical Safety Advice for Christmas Lights (Electrical Safety First)
20. Best Smart Plugs for Energy Savings: Real Math (Save and Upgrade)

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