Buying smart devices is shopping. Automating them is where a smart home actually starts to feel smart — where the house begins doing things for you instead of waiting to be told. The good news for renters is that the five automations with the biggest payoff are also the easiest to build, need only cheap, reversible gear, and run beautifully on Home Assistant — the free, local brain that keeps working with no internet and packs up with you when you move.

Below are the five to set up first, in order, with copy-and-adapt examples you can paste into Home Assistant’s YAML editor. Even if you never touch code, read the plain-English logic for each — the same ideas work in Alexa Routines, Google Home or Apple Home automations. A couple of beginner principles run through all of them, drawn from how experienced users actually build: keep “turn on” and “turn off” as separate automations (far easier to read and debug than one tangled rule), and always check whether the light is already on before a motion trigger fires, so the off-timer doesn’t keep resetting while you’re sitting in the room.

A note on the examples. The YAML below is illustrative — swap in your own entity names (the entity_id and area values) and adjust times to taste. Treat it as a starting template, not gospel.

1. Motion lights — the automation you’ll use a hundred times a day

This is the one that converts people. You walk into the bathroom or hallway and the light is simply on; you leave and a few minutes later it’s off. It needs one motion sensor and one smart bulb per room.

The trick that separates a good version from an annoying one is time-of-day awareness: blazing white light at 3 a.m. is hostile. So we make daytime motion bright and warm-white, and late-night motion a dim, warm glow — enough to find your way without waking up.

# Turn ON — dim & warm at night, brighter by day
alias: Hallway motion light ON
trigger:
  - platform: state
    entity_id: binary_sensor.hallway_motion
    to: "on"
condition:
  - condition: state
    entity_id: light.hallway
    state: "off"          # don't re-trigger if it's already on
action:
  - choose:
      - conditions:        # late night: gentle nightlight
          - condition: time
            after: "23:00:00"
            before: "06:30:00"
        sequence:
          - service: light.turn_on
            target: { entity_id: light.hallway }
            data: { brightness_pct: 10, color_temp_kelvin: 2200 }
    default:               # daytime / evening: useful light
      - service: light.turn_on
        target: { entity_id: light.hallway }
        data: { brightness_pct: 80, color_temp_kelvin: 3000 }

Then a separate OFF automation waits a few minutes after the last motion and turns the light back off — keeping on and off apart, as promised, so each is trivial to read and tweak.

# Turn OFF — a few minutes after motion stops
alias: Hallway motion light OFF
trigger:
  - platform: state
    entity_id: binary_sensor.hallway_motion
    to: "off"
    for: "00:04:00"        # no motion for 4 minutes
action:
  - service: light.turn_off
    target: { entity_id: light.hallway }

2. Away mode — stop paying to power an empty home

When everyone’s out, nothing should be running. This automation watches a presence signal — your phone leaving home, or simply no motion anywhere for a while — and switches off the lights and the smart plugs behind your TV, heater or chargers. It’s the automation that quietly pays for your gear in saved electricity.

alias: Away mode — everything off
trigger:
  - platform: state
    entity_id: person.you
    to: "not_home"
action:
  - service: light.turn_off
    target: { entity_id: all }
  - service: switch.turn_off
    target: { entity_id: switch.tv_corner }

Start gentle: switch off lights and a couple of known plugs rather than literally everything, so you don’t kill the fridge or router by accident.

3. Leak alert — the £15 sensor that saves your deposit

This one isn’t about convenience, it’s about disaster. A cheap water-leak sensor tucked under the kitchen sink, behind the washing machine or by the boiler can catch a slow leak before it becomes a ruined floor and a lost deposit. The automation does one thing and does it loudly: the moment the sensor goes wet, push a notification to your phone.

alias: Water leak alert
trigger:
  - platform: state
    entity_id: binary_sensor.under_sink_leak
    to: "on"
action:
  - service: notify.mobile_app_your_phone
    data:
      title: "💧 Water leak detected!"
      message: "The under-sink sensor is wet. Check it now."

For the full picture on which sensors to buy, see stick-on motion and door sensors — the same family of cheap, peelable devices.

4. Good night — one tap to shut the home down

At bedtime you don’t want to walk the flat turning things off. A single button (a cheap stick-on smart button, or a voice command) runs a “good night” scene: lights off, plugs off, and any morning alarms armed. The trigger here is a button press, but the same action block works from Alexa, Google or Apple if you’d rather say it out loud.

alias: Good night
trigger:
  - platform: state
    entity_id: binary_sensor.bedside_button
    to: "on"
action:
  - service: light.turn_off
    target: { entity_id: all }
  - service: switch.turn_off
    target: { entity_id: switch.living_room }

5. Gentle wake — lights that ease you up

The nicest way to start the day: instead of a jarring alarm, your bedroom light fades up slowly before you need to be awake, mimicking a sunrise. On dark winter mornings it makes getting up noticeably less brutal.

alias: Sunrise wake
trigger:
  - platform: time
    at: "06:45:00"
condition:
  - condition: time
    weekday: [mon, tue, wed, thu, fri]
action:
  - service: light.turn_on
    target: { entity_id: light.bedroom }
    data:
      brightness_pct: 100
      kelvin: 2700
      transition: 900       # fade up over 15 minutes

Build them in this order

Resist the urge to automate everything at once. Set up motion lights first — you’ll feel the payoff the same day — then add away mode, then the leak alert, and grow from there. Keep “on” and “off” as separate rules, always check the current state before acting, and name your entities clearly so a half-asleep version of you can still read them. Do that and these five will quietly run your home for years, surviving internet outages and following you to the next flat. New to the local brain that runs all of this? Start with how to set up Home Assistant in a rental.