Ideas & guides · Budget & buying

Can I Leave Holiday Decorations On All Night?

Is it bad to leave the yard lights and the inflatables running until morning?

5 minute read.

The safety answer, briefly, because it is the short one

An outdoor display left running overnight is safe under three conditions, all of which you should be meeting anyway: it is on a GFCI-protected outlet, the total load is inside what the circuit can carry continuously, and the connections are outdoor rated with drip loops.

On a standard 15 amp circuit the continuous working limit is 12 amps, which is 80 per cent of the rating. That convention exists precisely for loads like this one — something switched on at dusk and still going at midnight is the case the rule was written for.

If those three things are true, running until morning will not cause a fire or trip anything. If any of them is not true, the problem is not the hours; it is the thing that is not true, and it is a problem at 9pm as well.

The real reason to use a timer: blower hours

This is the argument that actually matters and it is almost never the one people give.

An inflatable's blower is a small motor running continuously, and it is the component that fails. It does not fail on a calendar; it fails on run hours. Dusk to sunrise is around fourteen hours a night in December. Dusk to eleven is about six. Over a six-week season that is roughly 590 hours against 250.

So the same inflatable either does one long season or something like two and a half, for a difference that costs twenty dollars once and takes five minutes to set up. That is a much better return than anything else on the list.

LED lights are effectively unaffected — they will outlast you either way. Incandescent mini lights do have a bulb life and do benefit. Anything with a motor, a pump or a fan benefits most.

What the hours actually cost

A mid-sized display: three inflatables and eight LED string sets, about 4 amps total, which is a little under 500 watts. Costed at 17 cents per kilowatt-hour over a six-week season.

Electricity rates vary enormously by state, so treat the dollars as a ratio rather than as a bill. The ratio is the durable part: cutting the hours in half cuts the cost in half, and the timer pays for itself inside the first season either way.

Which timer, and the one setting that matters

An outdoor-rated mechanical or digital timer with a photocell is the usual answer. Mechanical ones are cheaper and nearly indestructible; digital ones handle "dusk until 11" properly as the evenings change through December, which a mechanical one does not without resetting.

The setting worth thinking about is the off time rather than the on time. Dusk is obvious. The off time is a judgement about your street: a road people drive home along at eleven wants eleven, and a quiet cul-de-sac is honestly done by nine.

Buy one timer with enough outlets rather than one per piece. A single outdoor multi-outlet timer under an in-use cover is tidier, cheaper, and means the whole display goes on and off together, which matters more than it sounds like it should — a display that half-switches looks broken rather than switched off.

One caution, since this article also mentions GFCI: the timer goes downstream of the GFCI protection, not instead of it. A timer is a switch, not a safety device.

Where this usually goes wrong

Leaving it on because switching it off feels wasteful of the setup

The setup cost is sunk and the running cost is not. Nobody is looking at 3am, and the blowers are quietly using up the hours you paid for.

Using an indoor timer under an in-use cover

An in-use cover is not an enclosure rating. Use a timer that is itself outdoor rated; the indoor one in a plastic box is the thing that fails in the first wet week.

Putting the timer upstream of the GFCI

The order is outlet, then GFCI protection, then timer, then display. A timer ahead of the protection does not remove the protection, but a timer instead of it is a different and worse arrangement.

One timer per piece

They drift apart within a week, and a display where two of five things are lit reads as faulty rather than as off. One multi-outlet timer keeps the display a single object.