Smart Lighting Automation: Motion Sensors and Routines That Save Energy

Smart lighting automation means your lights turn on and off by themselves: at sunset, when someone walks in, or when the last person leaves home. Done well, it removes the most common lighting waste of all, which is lights left on in empty rooms.

The short answer
  • Smart lighting automation saves energy only where lights are often left on in empty rooms.
  • The best spots are garages, closets, laundry rooms, hallways, and outdoor lights.
  • Motion sensors use a small amount of standby power, about a watt, so they pay off only on lights that are often forgotten.
  • Below you’ll find a waste calculator and five ready-to-copy routines for Alexa and Google Home.
Wall light switch with a built-in passive infrared motion sensor
A wall switch with a built-in motion sensor, one of the simplest ways to automate a garage or laundry light. Photo by Z22, CC BY-SA 4.0, via Wikimedia Commons.

But automation is not magic. In a busy living room, a motion sensor can switch the lights off while you sit still. Start with the calculator, then copy the routines that fit your home.

How Much Do Forgotten Lights Cost You?

Forgotten-lights calculator
Add up the bulbs: e.g. 6 LEDs × 10 W = 60 W
The U.S. average is about 16–17 cents
Wasted per year–
Saving after sensor standby use–
Pays for itself in–

We subtract about 1 watt of standby use for the sensor, all day, all year.

What a forgotten light costs per year Left on 4 extra hours a day, at 17¢ per kWh One 9 W LED bulb $2.23 Fixture with 4 LEDs $8.94 One 60 W incandescent $14.89 Two 90 W floodlights $44.68 Sensor standby (1 W) $1.49 Our calculation. The sensor figure assumes about 1 watt, 24 hours a day.
Our chart. Automation pays off on old, bright or multi-bulb lights. On a single LED, the sensor saves very little.

Where Smart Lighting Automation Works Best

RoomBest automationWhy
Garage, closet, laundryMotion on, auto-off after 2–5 minutesShort visits, lights often forgotten
Hallway and stairsMotion at night, dim levelSafety without waking everyone
Outdoor lightsSunset to a fixed time, or motionStops lights burning all night
Kids' rooms and bathroomsVacancy sensor (turns off only)You switch on; it switches off
Living room, officeSchedules or "away" routine, not motionMotion sensors miss people sitting still

Five Smart Lighting Automation Routines to Copy

These work in the Alexa app (More → Routines) and the Google Home app (Automations). Names may vary slightly.

  1. Sunset porch light. When: sunset. Action: porch light on. Then: off at 11 p.m.
  2. Everyone left. When: the last person leaves home (location). Action: all lights off.
  3. Garage motion. When: motion sensor detects motion. Action: garage light on. Then: off after 5 minutes with no motion.
  4. Night hallway. When: motion between 11 p.m. and 6 a.m. Action: hallway light at 10% brightness for 2 minutes.
  5. Good night. When you say "good night": all lights off except the bedroom lamp, which dims over 10 minutes.

Watch: Occupancy vs. Vacancy Sensors

This short video from Lutron, a switch maker, explains the difference. An occupancy sensor turns lights on and off. A vacancy sensor only turns them off, which is often better for bedrooms and bathrooms.

What Real Owners Say

These are individual experiences, summarized in our own words.

"My family never turned a light off."

On the Garage Journal forum, one member said motion sensors saved him a lot on electricity, because nobody else in the house ever bothered to switch lights off. Another member in the same thread said motion lights frustrated him so much that he didn't want any more of them.

Source: Garage Journal forum
"The garage lights were always on."

A home blogger replaced a timer switch in a busy garage with a Lutron motion sensor switch. It keeps the lights on while it senses movement and turns them off after 1, 5, 15 or 30 minutes without motion. It works with the mix of CFL and LED bulbs they already had.

Source: Charles & Hudson

When Automation Won't Save You Much

  • You already switch lights off. There is little waste left to remove.
  • Rooms where people sit still. Lights turn off on you, and people disable the sensor.
  • Very low-wattage LEDs used briefly. The sensor's own standby use can match the saving.
How we put this guide together
  • Where lights are most often left on, by room
  • Standby power of sensors and the wattage of common bulbs
  • Routines that work in Alexa and Google Home without extra hubs
  • Real owners’ experiences, good and bad

We haven’t tested these products in person. No brand paid to be included.

Frequently Asked Questions

What is smart lighting automation?

It means lights turn on or off by themselves based on time, motion, sunlight or your location, instead of a switch.

Motion sensor or vacancy sensor?

A vacancy sensor only turns lights off. It avoids lights switching on when you don't want them, and many people prefer it in bedrooms and bathrooms.

Do I need a hub?

Not always. Many Wi-Fi and Matter devices work directly with Alexa or Google Home. Zigbee sensors may need a hub.

Our Verdict

Smart lighting automation is worth it in the garage, closets, laundry room, hallways, and outdoors. Start with one motion sensor and the "everyone left" routine. Those two cover most of the waste in a typical home.

Skip motion sensors in living rooms and offices. Use schedules there instead.

About the author

Khalid runs HomeEnergyHive. He is studying automotive mechanics and works hands-on in a repair shop, but he is not an HVAC installer or an electrician. For each guide he reads official data (ENERGY STAR, the U.S. Department of Energy, the EIA), manufacturer spec sheets and real owners’ experiences, and links the sources so you can check them.

No brand pays to appear on this site, and there are no affiliate links. How we research and check our guides.

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