Can you put a humidifier on a smart plug?

Two answers circulate, and both are right for one kind of humidifier#

In October 2023 a reptile keeper on Chameleon Forums put a humidifier on a Wi-Fi plug for a 1 am misting. It did not work. The first reply gave the common answer: "You should be able to leave the humidifier in the on position and allow the wifi plug to control on and off."

The owner had already done that. When the plug turned on, the humidifier "turns on but the screen is blank until I personally press the on button". So they still had to get up at 1 am.

Both posts are true. They describe two kinds of controls. The reply fits a humidifier with a switch or dial that stays in the on position. The problem fits one with an electronic button and a display, which wakes up with power but waits for a press. The brand and its manual decide which you have. A forum post about another model does not.

Three terms the answer turns on#

• Smart plug. A plug-in switch you control from an app, a voice assistant or a schedule. It can give the humidifier power or take power away. It cannot press a button.
• Positional switch. A rocker, slide or dial that stays where you put it, such as Off, Low and High. Cut the power and the switch is still on High. Restore it and the humidifier runs.
• Push-button control with memory. An electronic panel where a press turns the unit on and the settings live in a chip. Makers decide what it does when power returns. Some resume, some reset to a default, and some wait.

So the question is not "can the plug carry it". It is "what does this control do at the moment power comes back".

What each manual says happens when power comes back#

These are the six manuals read for this page, in November 2026. Watts are each maker's printed rating at 120 V.

Honeywell HCM-350: the control holds its place. The manual's setup steps are "Make sure unit is off", then plug in, then "Set fan speed" to High, Med or Low. To disconnect, "first turn controls to the OFF position". That is a control with a position. Leave it on Med, and power from the plug runs the fan at Med.

Vicks V745A: on with the power, until the tank runs dry. The manual tells you to turn "the Switch to either the Hi or Low position", and then "the heater will start". The switch stays put, so the plug can start it. The catch is the empty tank, covered below.

Boneco U350: back on, but in AUTO. The manual says the U350 "saves the last-used settings when it is switched off". It goes on: "if the appliance is disconnected from the power supply for a few seconds, it will start in the" AUTO operating mode. AUTO aims for 50% relative humidity. A plug that is off for hours wipes your setting every time.

Levoit OasisMist 450S: settings kept, start not promised. Levoit's memory function says the unit remembers mist level, warm mist and Wi-Fi settings "when turned off or unplugged, and will resume those settings when turned back on". Unplugged covers a plug cutting power, so the settings survive. But "turned back on" may mean the On/Off button. The manual never says the unit turns itself on when power returns. That is the gap the test below closes.

Levoit Classic 200S: silent. The 200S manual covers restarting after an empty tank but says nothing about power loss. Its own troubleshooting page notes that "Power outages, internet outages, or changing WiFi routers may cause your humidifier to go offline" in the app.

Crane EE-5202: one button. You "press the power button" for low, again for high, and "a third time to power off". The manual describes no other way to start it and says nothing about power returning. It also says: "Never leave the humidifier unattended while connected to the electrical outlet."

Is the plug rated for a humidifier?#

Yes, on every model read here. The largest, Crane's EE-5202, is 330 W. At 120 V that is 2.75 A. The Levoit 450S at 280 W is 2.3 A, and the Classic 200S at 24 W is 0.2 A.

Set that against a typical 15 A plug. Zooz rates its ZEN15 at "15 A, 1800 W", and its manual lists "(De)humidifiers" under "OK to use with". TP-Link says its plugs are "designed primarily for resistive loads, such as heaters". For "continuous long-term operation", it says to keep the load "at 80% or less of the maximum rated power". On an 1800 W plug that is 1440 W. The Crane uses less than a quarter of it.

None of these humidifiers has a compressor, which is what makes a dehumidifier hard on a plug. The manuals describe a fan, an ultrasonic plate, or a heater, and the heater is the resistive kind TP-Link names.

One figure confuses people. Crane's manual says any extension cord must be rated "at least 13 A., 1625 W." That is the cord's rating, not the humidifier's draw, which the same manual gives as 330 W.

Worked through: a 10 pm to 6 am schedule#

Here is one case, walked through the manuals. Suppose a smart plug turns a bedroom humidifier on at 10 pm and off at 6 am, every night.

With a Vicks V745A, switch left on Low. At 10 pm the plug turns on. The switch is still on Low, so the heater starts. The manual warns it "may take several minutes before mist will appear". At 6 am the plug cuts power. The manual says one tank gives "at least 12 hours of operation". So the first 8 hour night is fine. Skip the refill, and 16 hours of running is more than that minimum promises. The tank can run dry partway through the second night.

Then the manual's rule takes over: the heater "will automatically shut off", the Reset light comes on, and "The humidifier will not operate until the water tank is refilled and the humidifier is reset." At 10 pm on the third night the plug turns on, and nothing heats. Its reset steps start with the switch at Off and the cord out of the wall, then a refill. A plug can cut power. It cannot fill a tank.

With a Boneco U350, set by hand to 40%. At 6 am the plug cuts power. That is far longer than "a few seconds", so at 10 pm the U350 starts in AUTO, aiming for 50%. You set 40% and get 50% every night. If 50% suits you, this is fine. If not, use the U350's own timer, covered below, and leave the plug on.

With a Crane EE-5202. At 10 pm the plug turns on, and the manual gives no reason to expect mist without a button press. Even if yours does start, a warm mist unit on a schedule runs at night with no one awake. Crane's unattended rule rules that out.

Check yours in two minutes#

Do this with the cord in the wall, not the smart plug, so you test the humidifier alone. Wait 30 seconds, not 5. Boneco's reset happens after "a few seconds" without power, and a short pull may miss it. Then check the plug's own power-on setting, which decides what the plug does after an outage. What still works when the internet goes down covers that side.

Warm mist on a schedule: what the manuals say#

Warm mist units boil water. Vicks and Crane both warn, "Steam can cause burns." That changes what a plug should be allowed to do.

• Crane says never to leave the EE-5202 unattended while it is plugged in. A schedule that runs it while you are out or asleep goes against that.
• Vicks says the humidifier "should not be left unattended in a closed room", because the air "could become saturated". Leave the door partly open.
• Zooz lists (de)humidifiers as fine for the ZEN15. The same manual says not to use it "to control electric heaters or other appliances which produce the risk of fire, burns, or electrical shock when unattended". A cool mist unit fits the first line. A steam unit on an away schedule sits closer to the second.

The rule this page takes from them: schedule a cool mist humidifier freely. Use a plug on a warm mist one only while someone is home and awake, or as an off switch. The same idea runs through the space heater page and the electric blanket page: the maker's word on heat outranks the plug's rating.

Vicks also says "do not use an extension cord", and the Crane manual asks for its own circuit, "separate" from other running appliances. Plug the smart plug straight into the wall, with nothing else on it.

Using a humidity sensor to switch the plug#

The second most asked question is turning a humidifier on when the room gets dry. A SmartThings Community thread from January 2017 is a typical case. The owner paired a smart outlet with a humidity sensor and could not get the outlet to switch. A rule built in a third-party app made it work.

Whether you should do it depends on the control again.

On a positional-switch model, the plug can be the humidistat. The Honeywell HCM-350 manual lists only fan speeds, with no humidity setting. The Vicks V745A has only Low and Hi. On these, a sensor and a plug add what the unit lacks. For the numbers, the manuals help. Levoit says "A healthy humidity level is between 40% and 50%". Vicks says that above 50% you should turn it down or off. So turn the plug on below 40% and off at 50%.

On a model with its own humidistat, set the target on the unit. The Boneco U350 holds 30% to 70%. The Levoit 450S Auto Mode defaults to 60%, and its Automatic Stop ends misting at the target. A plug that also switches on humidity fights that loop. On the Boneco it also resets the target to 50% every time it is off for more than a few seconds. Automation design has the general rule against fighting a device's own control.

Put the sensor across the room, not in the mist. The sensors guide explains why placement decides whether a humidity reading means anything.

The empty-tank alert a metering plug can give you#

A metering plug reports watts, and an empty tank shows up in them. The Vicks heater "will automatically shut off" when the water is almost gone. The Levoit 450S turns off after its no-water light blinks 10 times. On the Classic 200S, the fan "will turn off after 5 seconds". Crane says the "mist output will stop".

So a sharp drop in power on a unit with no humidistat, such as the Vicks, means a dry tank. Set an alert for it. On a Levoit or Boneco in Auto, a drop can also mean the room hit its target. So pair the plug's reading with the room sensor, as the dehumidifier page does for a full bucket. The Zooz ZEN15 reports power to a Z-Wave hub such as Home Assistant, which keeps the alert local (local versus cloud control explains why that matters).

Better ways to schedule some of them#

• Levoit's app. Both Levoit manuals list timers and schedules in the VeSync app, so the unit keeps its own settings and no plug is needed.
• Boneco's timers. The U350 has an ON timer and an OFF timer. Unlike a plug, it keeps your setting.
• Matter, not yet. Humidifiers have no Matter device type, so through Matter a humidifier is a plug: on and off, nothing more.

For the other loads a plug should and should not switch, see smart plugs and what their energy numbers are worth.

Where this page stops#

This page covers six manuals: Honeywell HCM-350, Vicks V745A, Boneco U350, Levoit OasisMist 450S and Classic 200S, and Crane EE-5202, as of November 2026. Other models, even from the same brands, may behave differently, so run the test. The Honeywell and Vicks manuals print no wattage, so the page gives none for them. None of the six manuals mentions smart plugs. Whole-house humidifiers wired into a furnace are a different job and are not covered.

A schedule does not do the cleaning. Honeywell and Vicks both say the humidifier "should always be unplugged and emptied when not in operation". Vicks warns that water left in the tank "more than a day or two" can grow bacteria. Levoit says to change the water daily. A plug that cuts power leaves the water sitting in the tank, so daily emptying stays your job. For a warm mist unit, the unattended rule above holds whatever the plug can do.