Smart Plugs, Dimmer Switches and Smart Bulbs

Rating the plug: amps, watts and what you switch

A smart plug's rating is printed in amps, and watts equal amps times mains voltage: a 15 A plug on 120 V can handle about 1.8 kW, while a 10 A plug handles less. Add up the wattage of what you plan to switch. Lamps, fans and chargers are light loads. Heaters and air conditioners can draw close to the limit for long periods, kettles in short bursts, so use a plug rated for them and never daisy-chain adapters. Many smart plugs use 2.4 GHz Wi-Fi, so check which band your router offers during setup.

Bulbs, strips and dimmers: base, brightness and compatibility

Smart bulbs need the right shape and base, such as an A19 bulb with a standard screw base, and a brightness in lumens: about 800 lm replaces a 60 W incandescent bulb, and a 9 W LED can produce it. Some bulbs work over Bluetooth, and others need a bridge. Dimmer switches replace a wall switch, so check that your wiring matches, including a neutral wire if the listing requires one, and that the dimmer supports LED loads. Leave a smart bulb's wall switch on, since cutting power disconnects it. Light strips need their own power supply.

Questions about Smart Plugs, Dimmer Switches and Smart Bulbs

Can a smart plug control a space heater?

Only if the plug's rating exceeds the heater's draw with room to spare. Heaters pull close to the limit of a 15 A plug on 120 V for hours, so check watts on both labels and use a plug rated for heating appliances.

Do smart bulbs work with dimmer switches?

Usually it is better to keep the wall switch on at all times and dim through the app. A standard dimmer can cause flicker or stop the bulb from connecting, unless the bulb is listed as compatible with dimmers.

Do smart plugs keep working if the internet fails?

Schedules saved in the plug often continue to run, and local control may work on your home network. Voice commands and remote access usually need the internet, so check what the app does when offline.