In-cab comfort

Improve the fuel efficiency of your heavy vehicles by changing the way drivers heat and cool their cabs.

Use a staff newsletter to let drivers know how best to use the heating, ventilation and air-conditioning systems so that they save fuel but stay comfortable.


All vehicle heating systems use hot water from the engine's cooling system. That means an engine must warm up before water is hot enough to warm a cab.

  • Truck cabs will have some heating by the time the brake air pressures have built up, so there’s no need to idle trucks much longer than that.
  • Buses and coaches have more space to heat. To save fuel, limit idling to the time it takes to warm the cabin space.

Cooling and ventilation

If the vehicle's ventilation system does not provide enough cooling, drivers often open windows instead of using the air-conditioning system. At low speeds that’s fine, but at highway speeds, because of the extra aerodynamic drag created by open windows, it’s better to close windows and use the air-conditioning system.

Having windows open at higher speeds increases fuel consumption by as much as 7%, while using air-conditioning has no significant impact on heavy vehicle fuel economy.

Air-conditioning systems start to cool the vehicle as soon as they are switched on - they don't need the engine to warm up.