Photocell vs timer vs smart plug

A photocell instead of a clock. Sunset moves by about 25 minutes between early December and late January, and this is the only control type that tracks it without you doing anything.

A clock timer set to 5:00 pm in early December is fifteen minutes late by the solstice and about twenty-five minutes early by the end of January. Nobody reprograms it. The lights come on in daylight for the last three weeks of the season, which is the single most common thing wrong with an otherwise good display.

A photocell fixes that by measuring actual darkness. BN-LINK's dusk-to-dawn unit is rated 15 A, has two grounded outlets and an ETL listing.

The catch is the other end of the night. Pure dusk-to-dawn runs until sunrise, which is fourteen hours in December. If you want off at 11:00 pm, you need either a combined photocell-plus-countdown unit or a smart plug with a sunset-offset schedule.

Sensor placement decides whether this works. It needs a clear view of the sky and must not see your own porch light, a neighbor's floodlight or a streetlamp. We have seen a display that never came on all season because the sensor was eight feet from a lamp post.

Three grounded outlets, 7-day programming and a 15-amp rating in one weatherproof box. The amp rating is the spec that matters and this one does not cut it fine.

Buy the timer before you buy the last set of lights. Switching a display on and off by hand at an outdoor outlet lasts about four days before everyone gives up and leaves them on all night, which triples the running cost and shortens the life of everything.

The spec that decides a timer is its amp rating, and most people never look at it. An outdoor circuit is typically 15 amps. A timer rated at 10 amps plugged into that circuit is a 10-amp ceiling on your display whatever the breaker says, and exceeding it is how timers fail — often by welding their relay closed, which is a timer that never turns off again.

This DEWENWILS unit is rated 15 A with three grounded outlets and 7-day programming, and it is UL Listed. That last point deserves attention: certification is not universal in cheap outdoor timers, and it is the difference between a tested product and an untested one carrying your whole display.

Practical advice: program it indoors, on the kitchen table, before it goes outside. Digital timer interfaces are all bad, and they are worse in gloves, in the dark, at 25 degrees.

Three outlets also means one timer instead of three, which matters because each outdoor timer is itself a thing to weatherproof.

Two independently controlled outdoor outlets with sunset-offset scheduling. It is the only control type that gives you both automatic sunset tracking and a hard off time.

The control problem has two halves. You want the lights on when it actually gets dark, which moves through the season, and off at a fixed civilized hour. A clock timer solves the second and fails the first. A photocell solves the first and fails the second.

A smart plug with sunset-offset scheduling solves both: on at sunset plus fifteen minutes, off at 11:00 pm, and the on-time moves itself as the season progresses. That is the actual answer, and it is why smart plugs have displaced timers for people who already have decent Wi-Fi outside.

The KP400 has two independently switched outdoor outlets, so the roofline and the inflatables can be on different schedules from one device — useful, because an inflatable at 2:00 am is a different proposition from the roofline.

Two real cautions. Wi-Fi at an outdoor outlet on the far side of the house is often marginal; test coverage there before you commit the whole display to it. And check the combined amp rating against your load — smart plugs typically carry a lower rating than a 15 A mechanical timer, and that ceiling is easy to miss.