Smart plugs: what they're good for and what never to plug into one

A smart plug sits between an outlet and a device, letting you switch the power on and off from your phone, a voice assistant or a schedule. It's one of the cheapest ways to start with smart home features, as long as you plug in the right things.

Good uses

• Lamps on a schedule or a "sunset" timer.
• Holiday lights and other seasonal decorations.
• Fans and small appliances with simple mechanical switches.
• Checking energy use of a device, with plugs that offer energy monitoring.

What the plug can and can't do

A smart plug only switches power on and off. The device must turn on by itself when power is restored. A lamp left switched on works; a coffee maker that needs a button press after power returns won't brew just because the plug clicked on.

Don't use a smart plug for these

• Space heaters and other high-draw heating appliances. Many space heater makers say to plug directly into a wall outlet, and some smart plug makers say not to use their plugs with heaters. A heater running unattended is also a fire risk.
• Anything over the plug's rated load. Check the amps or watts on the plug's label.
• Medical devices and anything that must stay on.
• Outdoors, unless the plug is rated for outdoor use.

Compatibility

• Voice assistants: check that the plug works with the system you use (Amazon Alexa, Google Home, Apple Home).
• Matter: plugs that support the Matter standard work across several ecosystems and are easier to keep if you switch assistants later.
• Wi-Fi band: many smart plugs only connect to 2.4 GHz Wi-Fi. If your router combines bands under one name, setup can be tricky; check the instructions.
• Thread or Zigbee: some plugs use these low-power networks and need a compatible hub or border router.

Practical details

• Size: bulky plugs can block the second outlet. Slim designs leave it free.
• Physical button: lets you switch the device on and off by hand.
• Power-outage behavior: some plugs remember their last state; others default to off.
• Safety listing: look for a certification mark from a recognized testing lab such as UL, ETL or CSA.
• Local control: some plugs keep schedules working even when your internet is down.

Questions people ask

Do smart plugs use electricity when off?

They use a small amount of standby power to stay connected, typically much less than the device they control.

Can I use a smart plug with a power strip?

You can plug a power strip into a smart plug to switch several low-power devices together, as long as the total load stays within the plug's rating.

Are smart plugs safe?

Plugs listed by a recognized testing lab and used within their rating are generally safe. Avoid high-draw heating appliances and damaged or overheating plugs.