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Light- and Medium-Duty Vehicle Idle Reduction Strategies

An Argonne National Laboratory report (PDF 340 KB) estimated that more than 13 million light- and medium-duty trucks use more than 600 million gallons per year of fuel (gasoline and diesel) for idling. Download Adobe Reader. Consumers and fleets have become accustomed to idling vehicles for a number of reasons, but most drivers seem not to make the connection between idle time, increased emissions, and wasted fuel. For fleets, a good idle reduction policy is the first line of attack to save fuel and ensure vehicles are idling only when necessary. The second step is to consider the multiple equipment options available.

Three types of idle reduction technologies are available for light- and medium-duty vehicles: coolant heaters, air heaters, and energy recovery systems. In addition, there are certain things that every driver can do to reduce idling.

Coolant Heaters

Coolant heaters use the vehicle's regular heat-transfer system. The heater is mounted in the engine compartment; 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. Webasto and Espar manufacture coolant heaters appropriate for diesel and gasoline light-duty vehicles. These units cost $1,700 to $1,800 installed and use only one cup per hour of fuel compared with one gallon per hour typically used idling an engine.

Air Heaters

Drivers more concerned with passenger compartment warmth—such as taxi and limousine drivers—might prefer air heaters like the one offered by Webasto. Although they operate on engine fuel, air heaters are separate, self-contained units that directly blow hot air into the vehicle interior. Like coolant heaters, they have only a small draw on the battery, use similar amounts of fuel, and have comparable installation costs.

Energy Recovery Systems

Another option for keeping a vehicle warm is an energy recovery system from Autotherm. This system uses the vehicle's heat-transfer system much like a coolant heater but without a separate heater. A very small (1/10 amp) electric pump is connected to the water line, which keeps the car's cooling system and heater operating after the engine is turned off, using engine heat that would otherwise dissipate. Installation costs run about $700.

Things Every Driver Can Do To Reduce Idling

  • Turn off your engine when you are parked or stopped (except in traffic) for more than a minute.
  • Consider the purchase of a hybrid electric vehicle, which limits idling at traffic stops.
  • Avoid using a remote vehicle starter, which encourages unnecessary idling.
  • Avoid drive-thrus: walk inside instead.
  • Encourage your local schools to enforce a no-idle zone for school buses and personal vehicles.