Sleep Mode

A comfort mode on thermostats or AC units designed for nighttime use. In sleep mode, the system gradually adjusts the set temperature (often raising the cooling setpoint or lowering the heating setpoint by a couple of degrees) and may reduce fan speed to save energy and lower noise while occupants sleep. In cooling, for instance, sleep mode might slowly increase the temperature a few degrees over several hours. Many air conditioners also run quieter in sleep mode by limiting compressor and fan speed.