Uses warm heat over long period of time to increase temperature.  You can’t leave this off until you want heat because it could take an hour for the HP07 to warm the room.  In addition, you can’t turn the heat on an hour prior to entering the room because the app isn’t allowed to turn on heat.  Seems our government won’t let us burn our houses down with space heaters but it’s okay to set leaves on fire and inhale it as long as they are collecting taxes from it.