California Air Resources Board

Battery-Electric Auxiliary Power Systems
Using advanced battery packs, battery-electric auxiliary power systems provide heating, cooling, and electrical power to ancillary cab appliances. These systems are designed so that the primary engine charges the batteries during normal road operation. However, certain systems equipped with the capability to "plug in" also allow operators to use shore power to charge the battery and/or power the system. The battery packs require approximately 2-6 hours of charge time and can run the air conditioning system for up to 12 hours per full charge. The option to "plug in" is available at participating layover locations.
 

Vehicle-Battery Systems
Vehicle-battery systems are less expensive alternatives more commonly used in day cab applications. Currently, vehicle-battery systems on the market offer either cab heating or cab cooling, but not both. Some examples of vehicle-battery systems include heated coolant recirculation systems, evaporative cooling systems, and window fans. Although these systems typically offer limited services, they can be paired with other devices. For example, pairing an evaporative cooling system with a fuel-fired heater can provide a more complete climate control package.
 

Truck Stop Electrification (On-Board Power Infrastructure)
By installing on-board electrical hardware and an electrically-powered climate control system, drivers can "plug in" their vehicles and draw electricity directly from the power grid. The electricity can be used to provide cab heating and cab cooling, to power cab appliances, and to charge the vehicle's battery. Access to the grid is achieved through outlet pedestals installed at participating layover locations.
 

Truck Stop Electrification (Off-Board Power Infrastructure)
For an hourly fee, providers may offer heating, cooling, television service, telephone service, and internet service through a duct that attaches to the vehicle through an adapter (one-time purchase) fitted into the vehicle's side window opening. Electrical outlets are also provided for powering ancillary cab appliances such as microwaves and televisions. Since direct heating and cooling are provided, vehicle operators can avoid the costs of purchasing and installing on-board electrical and climate control equipment. Service is available at participating layover locations.
 

Thermal Energy Storage Systems
A Thermal energy storage system stores cooling energy from the vehicle's air conditioning system during normal road operation. The stored energy can be used to cool the cab at a later time when the engine is off. This system only provides cooling, but can be paired with a fuel-fired heater for a more complete heating and cooling package.

Diesel-Fueled Auxiliary Power Systems
Diesel-fueled auxiliary power systems use small diesel engines to generate power for cab heating, cab cooling, and operating ancillary cab appliances. These units can also be used to heat the engine block in cold weather and recharge the vehicle's battery. Because of the engine's smaller size, operating a diesel-fueled auxiliary power system uses only a fraction of the fuel that would be used by idling the vehicle's primary engine

Note: For trucks with 2007 and newer model year engines, additional requirements apply. Please see "approved and verified equipment" for a list of diesel-fueled auxiliary power systems approved for use on these vehicles. For trucks with 2006 and earlier model year engines, any California- or federally-certified internal-combustion auxiliary power system may be used.
 

Fuel-Fired Heaters (Fuel Operated Heaters)
Fuel-fired heaters provide heat to the cab and the engine block, and use only a fraction of the fuel that would be used by idling the vehicle's primary engine. They can also be paired with other cooling technologies for a more complete heating and cooling package.

Note: For trucks with 2007 and newer model year engines, additional requirements apply. Please see "approved and verified equipment" for list of fuel-fired heaters approved for use on these vehicles.
 

Note: CARB does not endorse the purchase or use of products and/or services from any specific vendor/provider and makes no claims as to the effectiveness or operation of these products and services. Furthermore, determining the suitability of any specific cab comfort system and its legal use within California is the sole responsibility of the purchaser/operator. Please see CARB's Conditions of Use document for additional conditions pertaining to the use of CARB's website.