Cooling and electric capacity is generated and stored as the truck is running or connected to shore power. When off, the battery systems supply power to the cab. A thermostat regulates the driver's desired sleeper temperature and dial controlled fans circulate warm or cool air through the bunk areas.

Extensive testing shows that Kenworth Clean Power and Peterbilt Comfort Class can keep the sleeper cool for 10 hours, even with ambient outside temperatures of up to 95 degrees.