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U.S. Department of Energy Energy Efficiency and Renewable Energy

Medium-Duty Vehicle Idle Reduction Strategies

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How Much Can I Save?

Use the Idle Reduction Savings Worksheet to calculate your potential savings.

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Typical medium-duty trucks include utility, courier, and package delivery trucks. Drivers commonly idle for comfort while waiting in queue to make pick-ups or deliveries. Changing driver behavior and applying idle reduction technologies can help save fuel and reduce emissions.

Change Driver Behavior

For medium-duty trucks, the primary idle reduction strategy is to turn the vehicle off when parked or stopped for more than a few seconds (except in traffic). Drivers can also:

  • Avoid using a remote vehicle starter, which encourages unnecessary idling.
  • Obey no-idle zones at schools and other locations.
  • Consider the purchase of electric drive vehicles, which limit idling at traffic stops and while waiting in queue, and/or workplace hybrids that can support power take-off.

Adopt Idle Reduction Technologies

Alternatives to idling for medium-duty vehicles depend on how the vehicle is used. Most medium-duty truck idling happens during working hours. The idling may be confined to short stretches of time, or it might be quite long, as in the case of utility trucks that are parked for extensive periods of time, but need power for working purposes. Possible idle reduction technologies include:

  • Air Heaters

    Air heaters are useful for medium-duty truck drivers who idle primarily for comfort in the passenger compartment. Although they operate on engine fuel, air heaters are separate, self-contained units that blow hot air directly into the vehicle interior.

  • Coolant Heaters

    Coolant heaters use the vehicle's regular heat-transfer system and are mounted in the engine compartment. The heater draws gasoline or diesel from the fuel tank to heat the vehicle's coolant and pumps the heated coolant through the engine, radiator, and heater box. Coolant heaters keep the engine warm, reducing the impact of cold starts.

  • Energy Recovery Systems

    Another option for keeping a vehicle warm is an energy recovery system, which uses the vehicle's heat-transfer system much like a coolant heater but without a separate heater. A very small electric pump is connected to the water line, which keeps the vehicle's cooling system and heater operating after the engine is turned off, using engine heat that would otherwise dissipate. As with coolant heaters, energy recovery systems keep the cab warm.

  • Battery/Auxiliary Power Systems

    For medium-duty trucks that require power take-off throughout the day, a secondary power plant, storage battery, or hydraulic storage system can be an excellent solution. In the case of a battery, it can be mounted in the back of the truck and charged overnight and recharged if needed during the day. For more information, see conversions to plug-in hybrid electric (PHEV) vehicles. In the case of an auxiliary power unit, it can have a small diesel engine like a generator, which uses less fuel and produces fewer emissions then an idling vehicle's main engine would.