AC Systems in Commercial Motor Vehicles and Fuel Economy

Semi-trucks parked at truck stop, dawn
••• Walter Hodges / Getty Images

When driving eight to 10 hours a day in a commercial truck, having a working and efficient air conditioning (AC) system is key. A good AC system keeps you cool and comfortable in the driver's cab and has a good effect on your performance and driving safety. But while it may be a necessity for your comfort, have you ever wondered how the constant run of an AC system affects your truck? 

Unfortunately, not only do AC units affect fuel consumption in your commercial motor vehicle by increasing fuel consumption by 10% (for some vehicles), but studies show AC can affect your truck's engine, causing your vehicle to run more slowly.

HowAC Systems Affect Fuel Consumption

Depending on the type of vehicle you drive, the conditions under which both your truck and the AC system have to operate and the type of air conditioning system you have, your vehicle's fuel consumption may be increased by up to 10%.

Some of the operation conditions include outside temperature, humidity, solar radiation, cabin temperatures and comfort level, the size of the cabin, road grade and aerodynamic drag, driving speed and the length of time AC is in use, among other factors.

What the Future Holds

Historically, the burden of AC usage in commercial motor vehicles (CMV) has been quite large, so many car manufacturers, scientists and engineers have been working around the clock to develop new and more fuel-efficient ways and strategies to be comfortable in the driving cabin. Some of these ideas include:

  • Using the constant energy released by coasting to a stop (instead of solely relying on fuel)
  • Throttling the air conditioning system when the car starts up to supply the engine with full energy. 
  • Designing and developing fuel-efficient cars that do not rely on gasoline to function

Conserving Fuel Consumption

In addition to mindful AC use, some of the ways in which the driver of a CMV can help reduce fuel consumption include:

  • Avoiding aggressive driving (i.e., hard accelerations and hard braking). This type of driving can increase fuel mileage by as much as 30% at highway speeds, according to the official U.S. government source, an excellent website for detailed information on the topic
  • Removing excess weight from the vehicle
  • Avoiding aerodynamic drag on a semi-truck or bus
  • Keeping the engine in tune
  • Ensuring tires are inflated to the recommended air pressure which improves fuel mileage by 3-4%
  • Planning routes for efficiency and consolidating trips
  • Driving a fuel-efficient vehicle