Smart plugs & automation basics

Control and measure appliances, build schedules, and cut standby waste with Wi-Fi or Zigbee smart plugs.

Smart plug controlling a lamp with energy monitoring on a phone
Why smart plugs? They turn ordinary appliances into controllable, schedulable loads — and many models also measure power (W) and energy (kWh) so you can spot energy hogs.

What is a smart plug?

A smart plug is a mains adapter with a built-in relay and radio (Wi-Fi, Zigbee, Z-Wave, Thread, etc.). It sits between your wall socket and appliance, letting apps and automations switch power on/off and sometimes read energy use.

Zigbee vs Wi-Fi — which should I choose?

Zigbee (recommended for Home Assistant)
  • Creates a low-power mesh — range improves as you add devices.
  • Less interference with your home Wi-Fi network.
  • Works locally via a Zigbee coordinator (e.g. Sonoff Zigbee 3.0 USB, ConBee II).
Wi-Fi
  • Simple setup; no hub required.
  • Can load your router with many devices; cloud-tied brands may be slower.
  • Prefer models with local control (e.g. ESPHome/Tasmota) for speed & privacy.

Common uses

  • Schedule lamps, aquarium/heater, routers or ONT reboots.
  • Cut phantom/standby loads (gaming consoles, media boxes, chargers).
  • Automate coffee machine/kettle in the morning, or pool pump off-peak.
  • Power-cycle LTE routers during outages to force reconnection.

What to look for when buying

  • Current rating: Choose 16 A plugs for kettles, heaters and high-draw devices. Check your country plug type and safety approvals.
  • Energy monitoring: Look for models with accurate power metering (kWh, W, V, A).
  • Local control: Zigbee or Wi-Fi models that work without cloud for speed & privacy.
  • Form factor: Compact body so it doesn’t block adjacent sockets.

Setup (Home Assistant)

  1. Zigbee: Plug in your Zigbee USB coordinator → add integration (ZHA/Zigbee2MQTT) → put smart plug in pairing mode → add device.
  2. Wi-Fi (ESPHome/Tasmota): Flash or buy pre-flashed → add to Home Assistant via ESPHome or MQTT → confirm you have entities for switch and power sensors.
  3. Name entities clearly (e.g. switch.kettle, sensor.kettle_power).

Five quick automations

  • Sunset lamp: Turn on living-room lamp 20 min before sunset, off at 23:00.
  • Boil-guard: If kettle power < 3 W for 5 min, turn off (left on empty).
  • Standby killer: If TV power < 2 W for 10 min, cut power to TV + console.
  • Load-shedding helper: On grid-restored event, power-cycle router once.
  • Pool pump off-peak: Run only during low-tariff hours (check your utility).

Safety notes

  • Stay within the plug’s rated current and appliance type (no stoves/geysers/heavy inductive loads).
  • Avoid daisy-chaining multiple adapters or using damaged extension leads.
  • For heaters/ovens, consider hard-wired smart switches or a dedicated contactor installed by an electrician.

FAQ

Do smart plugs increase energy use?

A fraction of a watt to a couple of watts. You’ll usually save more by cutting standby waste.

Can they measure energy accurately?

Good models are close enough for household use. For billing-grade accuracy, use a dedicated meter.

Will they work on backup/inverter power?

Yes — but large surge loads may trip; stay within ratings and inverter limits.

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This guide is informational. Always follow manufacturer instructions and local electrical codes; use a qualified installer where required.