Auxiliary Power Units - HVAC
An APU is an alternative to running the truck's main engine using a secondary auxiliary power source. This provides you with comfort and convenience thanks to its separate cooling and heating and generally a 120 volt AC power source.
Having an APU will result in reduced fuel consumption by not running the trucks engine during non driving hours and it also extends your truck engine's lifespan by not running it during off hours. APU Manufacturers: