What should you never put on a smart plug?

Anything whose failure mode is dangerous or expensive, and anything with a mechanical switch that has to be pressed after power returns. That rules out space heaters and irons on most plugs, medical equipment, refrigerators and freezers holding food, sump pumps, and aquarium life support. It also rules out devices that draw more than the plug is rated for. Check the plug rating against the appliance nameplate before plugging anything in, using the figures in our wattage guide.

Can a smart plug make a dumb appliance smart?

It can make it schedulable, not intelligent. A smart plug controls power, so it works beautifully on anything that resumes its previous state when power is restored — a lamp, a fan with a mechanical dial, a string of lights, a slow cooker with a physical switch. It does nothing useful for a device with an electronic standby button that has to be pressed after a power cut, which is why smart plugs on modern televisions and microwaves so often disappoint.

Do smart plugs work with any smart speaker?

Most work with Alexa and Google Assistant, fewer with Apple Home, and the reliable answer is to look for Matter certification. A Matter plug works with all the major platforms without a brand bridge, which matters because plugs are the devices people accumulate over years from whichever brand was cheapest. Mixed-brand collections are exactly the mess Matter was created to fix, and it is worth the small premium on new purchases.

Can a smart plug measure how much an appliance costs to run?

Models with energy monitoring can, and they are the cheapest way to answer that question. The plug reports watts in real time and kilowatt-hours over the month, and you multiply the total by your own rate from your utility bill. Accuracy varies between models and is generally good enough for comparing appliances even where it is not calibrated to a utility standard. Leave one on a suspect appliance for a full month rather than a day, because duty cycle matters more than peak draw.

Are outdoor smart plugs different from indoor ones?

Yes, and the difference is not optional. Outdoor models carry a weather-resistant enclosure and a listed rating for wet or damp locations, and they should be used on a GFCI-protected exterior receptacle. An indoor plug in an outdoor extension box is a shock and fire risk regardless of how sheltered it looks. Check for a recognized safety certification mark on any plug you buy, indoor or outdoor, since the category is full of uncertified imports.

What Can You Do With a Smart Plug? (12 Genuinely Useful Jobs)

Written & researched by Derek Holt Home & Appliances Editor

Updated October 2026

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A smart plug switches any plug-in device on and off from an app, a schedule, a voice command or a trigger — so its usefulness depends entirely on whether the device resumes its previous state when power returns. It is excellent for lamps, holiday lights, fans, humidifiers, dehumidifiers, coffee makers with a physical switch, slow cookers, electric blankets and Christmas trees. It is useless for anything with an electronic standby button that must be pressed. Models with energy monitoring also measure exactly what an appliance costs to run, which is often the most valuable thing they do.

Which jobs does a smart plug actually do well?

The rule is simple: if the appliance has a mechanical switch and works the moment power arrives, a smart plug controls it perfectly.

Lamps. The classic. A floor lamp on a schedule beats a smart bulb when the fixture takes an odd bulb or has a shade you like.
Holiday and outdoor lights. On at dusk, off at midnight, with no timer to reset when the power blips.
Occupancy simulation. Randomized lamp schedules while you are away, which is a genuine deterrent per the offender research covered in do security cameras deter burglars.
Coffee makers with a mechanical switch. Grounds and water loaded the night before, brewing at 6:30.
Dehumidifiers and humidifiers. Run them on a schedule or tie them to a humidity sensor.
Fans. Box fans and tower fans with a physical dial, on a timer overnight.
Electric blankets and mattress pads. Warm the bed for 30 minutes, then off.
Killing standby loads. Consoles, printers and older AV gear, which is where the plug pays for its own draw — see do smart plugs use electricity when off.
Energy detective work. Metering plugs find the appliance quietly costing you money.
Battery chargers. Cut power after a set period rather than leaving a charger on a workbench indefinitely.
Grow lights and aquarium lighting. Reliable photoperiods, covered further in how many hours a grow light should be on.
Rebooting a router or modem. A scheduled overnight power cycle, with the caveat that you lose remote control of the plug while the network is down.

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Where do smart plugs disappoint?

Three categories, and knowing them in advance avoids most of the one-star reviews in this product class.

Situation	Why it fails	Better answer
Modern TV, microwave, air fryer	Electronic standby needs a button press	Leave it plugged in; use an IR or HDMI-CEC remote
Space heater or iron	High wattage and a real fire risk unattended	Do not automate; use a heater with a built-in timer
Refrigerator or freezer	An accidental off spoils food silently	Never plug one in
Sump pump or medical device	Failure has consequences	Direct to the receptacle
Ceiling light on a wall switch	Nothing to plug in	A smart switch — see smart plug vs smart switch
Outdoor use with an indoor plug	No weather rating; shock and fire risk	A listed outdoor plug on a GFCI receptacle

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What should you look for when buying one?

Four specifications and one certification. Check the wattage and amperage rating against what you intend to plug in, which is set out in how many watts a smart plug can handle. Prefer Matter certification so the plug works with Alexa, Google Home and Apple Home without a brand hub. Get energy monitoring on at least one plug even if not all of them. Check the physical size, because a fat plug blocks the second outlet in a duplex receptacle. And buy from brands carrying a recognized safety certification mark, since this category attracts uncertified imports.

The plugs owners rate most highly for reliable schedules, accurate metering and staying connected are in our smart plug picks, and if yours keeps dropping off the network the causes are in why a smart plug keeps going offline.

We never buy, install or physically handle the products we rank. Every recommendation comes from aggregated owner reviews, star ratings, review volume and published expert consensus — see how we rank.

What Can You Do With a Smart Plug?

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Which jobs does a smart plug actually do well?

Where do smart plugs disappoint?

What should you look for when buying one?

Frequently Asked