Idle reduction is about cost savings and driver comfort.

Executive Summary

Battery-powered heating, ventilation, and air conditioning (HVAC) systems help fleets deal with cab climate control, by providing climate control to the truck cabin while the truck is parked. Fleet users benefit because the systems are quiet and produce no emissions, but they may not provide enough cooling capacity for long rest periods or when operating in very hot temperatures. 

They can be powered by a set of batteries on the tractor or come with a plug-in capability for battery charging and/or operation while connected to an electrical power source. They are also called battery APUs and battery EPUs. 

Introduction to Idle Reduction
Available Systems

Some of the systems operate on 12V power generated from a bank of Group 31 Absorbed Glass Mat batteries and use an inverter to convert DC power to AC power. Others simply operate on 12V DC power. Cooling capacity ranges from 4,600 to 10,000 Btu/hour.

Common Fleet Strategies

Battery HVAC systems are one of the anchor technologies of an overall idle-reduction strategy. Here are some of the common fleet strategies for adopting these systems successfully.

  • To get the best cooling add extra insulation.
  • Add a fuel-operated heater to more efficiently cover all climate zones.
  • Add an automatic start/stop system to charge the battery when the truck is stopped for extended periods of time. This will allow the system to operate longer.
  • Use in conjunction with off-board AC power/truck stop electrification to overcome the limited hours the battery HVAC system can function.
What Others Are Saying
Decision-Making Tools

There are already a wide variety of payback calculators for any given type of idle-reduction system. In an effort to meet the industry’s need for more information, we have also developed a high-level payback equation to aid fleets in choosing the right combination of technologies.

Decision-Making Tools


Some truck manufacturers offer battery HVAC systems as factory options. Here is a breakdown of what the truck manufacturers offer:

  • Freightliner offers ParkSmart
  • Peterbilt offers SmartAir (Bergstrom Nite)
  • Kenworth offers K.I.M.S.
  • Volvo offers a prep-kit for off-line APU installation
  • Mack offers Idle Free as an off-line option
  • International offers MaxxPower (Bergstrom Nite)

Battery HVAC systems are seen by some as zero-idle solutions because they do not use any kind of engine when in operation. These systems capture energy produced by the truck engine’s alternator when the truck is running and stores it in AGM batteries. When the truck engine is turned off, the energy stored in the batteries can be used to power air conditioning and hotel loads and in some cases heating systems. To get the most from battery HVAC systems, drivers should pre-cool their trucks, pull curtains between the cab and sleeper and use window shades.