Power, Cords & Timers
How much does it cost to run Christmas lights?
One formula, your own rate, your own wattage. Here is the calculation rather than somebody else's number.
Mike M. — The hands-on owner behind Iron Mako Media.
Published
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The formula: total watts ÷ 1,000 × hours per night × nights × your rate per kWh. That is the whole calculation, and the only two numbers you need are the wattage printed on your light sets and the rate printed on your electricity bill.
We are not going to quote a dollar figure for a 'typical' display. Electricity rates vary by a factor of three or more across the country and light sets vary even more, so a national average would be wrong for almost everyone reading it. Your own two numbers give you the right answer in about a minute.
Work it out in four steps
- 1
Total your watts
Add the wattage printed on the plug tag of every set, plus inflatable blowers and projectors. See Christmas light amps and watts.
- 2
Convert to kilowatts
Divide by 1,000. A 600-watt display is 0.6 kW.
- 3
Multiply by hours and nights
Hours per night times the number of nights the display runs. Six hours a night for 40 nights is 240 hours.
- 4
Multiply by your rate
Find the per-kWh rate on your electricity bill. 0.6 kW x 240 hours = 144 kWh, times your rate, is the season's cost.
| Hours per night | Nights | Total hours | kWh for a 600 W display |
|---|---|---|---|
| 4 | 30 | 120 | 72 |
| 6 | 40 | 240 | 144 |
| 8 | 45 | 360 | 216 |
| 14 (dusk to dawn) | 45 | 630 | 378 |
That last row is the case for not running dusk-to-dawn. A pure photocell with no countdown more than doubles the running hours versus a sensible 6-hour schedule, for no benefit after about 11:00 pm when nobody is looking at it.
The LED difference, quantified for your display
Rather than quoting a saving, run the formula twice: once with the wattage on your current sets and once with the wattage on the LED equivalents you are considering. The ratio between those two totals is your actual saving, and for incandescent-to-LED it is an order of magnitude rather than a percentage.
That multiplier applies to the running cost, the circuit budget and the number of sets you can chain end to end — three separate benefits from one change. See LED vs incandescent.
Cutting the running cost
- Switch incandescent runs to LED. By far the largest single change, and it also frees circuit capacity.
- Use a fixed off time rather than dusk to dawn. Off at 11:00 pm instead of sunrise roughly halves the hours. A smart plug does this while still tracking sunset — see best outdoor smart plugs.
- Run the yard pieces on a shorter schedule. Inflatables and projectors can go off earlier than the roofline; they are the pieces nobody is looking at late.
- Shorten the season slightly. Five fewer nights is a straightforward proportional saving.
- Do not use solar to save money. It saves electricity and costs more up front; buy it because a cord cannot reach, not as an economy measure.
What about the inflatables?
Inflatable blowers run continuously while the unit is up, which sounds expensive and is not — these are small fans. Include them in the total honestly, but they are rarely the dominant line. Inflatable power draw has the detail.
If you want to reduce it anyway, put inflatables on a separate outlet with an earlier off time. A deflated inflatable at 11:00 pm costs nothing and nobody notices.
What to buy
The products that fit the advice above, chosen by the process on our methodology page. We have not hands-on tested them; specifications are the manufacturers’ own.
Quick picks
| # | Product | Best for | Score | Price |
|---|---|---|---|---|
| 1 |  Top pickKasa Smart Outdoor Plug (KP400)2 independent outlets, sunset offset | Sunrise/sunset scheduling and phone control | 8.8 | Check price on Amazon |
| 2 |  BN-LINK Outdoor Timer with Dusk-to-Dawn Sensor, 15APhotocell dusk-to-dawn, 15 A, 2 outlets | Set it once and never touch it | 8.9 | Check price on Amazon |
| 3 |  Wintergreen Lighting OptiCore C9 LED, 25 ft25 bulbs / 25 ft, 12 in spacing | Rooflines you want to keep for a decade | 9.2 | Check price on Amazon |
#ad We may earn a commission · Prices are shown by Amazon, not by us
Scores are our own editorial judgment from published specifications and buyer feedback — not aggregated user ratings, and not from hands-on testing. See how we pick.
Jump to a full review below: power-and-timers
Common questions
How much does it cost to run Christmas lights for a month?
Total the wattage on your sets, divide by 1,000, multiply by hours per night and nights, then multiply by your electricity rate per kWh. Rates vary by a factor of three across the country, so your own bill is the only figure worth using.
Are LED Christmas lights cheaper to run than incandescent?
Substantially — the difference is an order of magnitude rather than a percentage. Run the formula twice, once with each set of wattages, to see the figure for your own display.
Is it expensive to leave Christmas lights on all night?
It more than doubles the running hours compared with a six-hour schedule, for no benefit after everyone is asleep. Use a fixed off time, or a smart plug that tracks sunset for the on-time and holds a fixed off-time.
Do inflatables cost a lot to run?
Less than people assume. The blower is a small fan and the lighting is LED. Include it in your total, but it is rarely the dominant part of a display's running cost.
Sources
Every specification quoted on this page comes from the manufacturer’s own published information or a current retail listing, linked below. Where a figure is not published, we say so rather than estimating it.