Regulate your AC usage while maintaining comfort, saving you tons of money in the process! There are two parts to this product. The first is a door sensor that detects when people leave the apartment and the second is a ceiling-mounted device that senses whether or not there are any people still inside. If no one is present in the room for 15 minutes, it then sends an IR signal to turn the AC off. This maintains your comfort in that the AC is only turned off when there is no one inside and it maximizes energy savings by making sure the AC is only turned on when it’s needed!