A:Answer No, you’re right, the furnace or air conditioner will run regardless, but will run based on the room you tell it to obey. For example, my mother-in-law is always cold, so the sensor is “active” in her rooms during the times that the she’s home, meaning it won’t let the AC run more than the setting in her room at certain times (or heat—will warm her rooms up), even if that means the living room is cooler or warmer.