How to Use Smart Tech to Save on Your Light Bill

If you are constantly fighting with family members or roommates about turning lights off when they leave a room, automation can help. This isn't advanced stuff, either: You simply use sensors to detect when someone is or is not in the room. When there isn’t activity, the lights turn off.  

Choosing the right sensor

To start, you need sensors, and there are two types you should look at. The first is a motion sensor, which is exactly what it sounds like. The second is newer—a presence sensor. A presence sensor can tell if you’re just chilling in the room, rather than moving around in it. If you’ve been sitting quietly reading or watching TV, the lights shouldn’t go out on you. 

Aqara, a company that makes everything from vibration sensors to water leak monitors, made a huge splash last year with its Presence Sensor FP2. It’s a small hinged sensor that can be ceiling- or wall-mounted, aimed into a direction, then calibrated, before using AI to continually train itself. Depending on how you aim it, it can either detect or discount pets (or low-lying relatives, I suppose). 

Whether you’re using a motion detector or a presence detector, the basic automations remain the same: one to trigger lights on, and one to turn them off if a check isn’t met. 

Setting the lights to come on when someone is in the room

For the first automation (I'm using Google Home), choose a household routine so you can use a device as the trigger. Choose the sensor in question (I’m using the FP2 here). Choose “Detects motion” and then move onto the “Time and days” section.  Think about whether these rules should always be true, or only during the daytime. If someone gets up in the middle of the night, should every room light up as they walk through it? Set up the time and days that make sense for you. 

Once you’ve set that up, it will return to the previous panel, and you can click “Add action." Click “Adjust home devices” and now you’ll be selecting the light in this particular room. Perhaps it is a lamp plugged into a smart plug, or just a lightbulb. In any case, find the device, and then set it to turn on and click "save." If you have multiple lights in this room, you’ll have to add each one as an action here in this automation, since each automation can have multiple triggers and multiple actions. 

Another idea to consider is that if it is after say, 11 p.m., you might want a light to go on, but not at full brightness. If the smart bulb you’ve chosen supports it, you can, in actions, choose to turn the bulb on at 20% brightness. 

Once all the actions are added, it’s time to save the automation. 

Setting the lights to go off when someone leaves the room

To create the second automation that turns the lights off, you’ll do the whole thing over again, but this time, in Triggers, choose “When doesn’t detect motion.”  You should be asked a follow-up question about how long motion hasn’t been detected for. So, in the example below, you see I’ve set it for five minutes. After five minutes of no motion sensed, it will kill the lights. 

Set the conditions and days, choose the same lights you did before, but now, tell them to turn off. 

Testing and troubleshooting the automations

All that’s left is to test the automations. Using your smart hub, turn the lights in question off. Now, enter the space, and see if they turn on. If they pass the test, leave the space and see if they turn off after the appropriate amount of time passes. You don’t have to be in the room to check, since that would set the sensor off: Just check the device status in your hub. 

If the lights didn’t turn on, check the automation log and make sure the automation fired. If it did fire, but the lights didn’t go on, make sure the time and days were set correctly and you chose the right light and action. You can also check to make sure the sensor is calibrated correctly.