Summer is over, and winter is approaching. Keeping drivers warm, comfortable, and safe in cold weather is critical. But with diesel fuel hovering around $6 a gallon, idling can put a dent in fleet profitability. Consider this: A typical Class 8 truck idles at around 0.8 gallons of fuel per hour, resulting in 1,000 to 1,800 gallons of diesel burned annually per vehicle, depending on climate, duty cycle, and usage patterns. Even when fuel is $4 a gallon, a single long-haul truck might waste $4,000 to $6,000 worth of fuel each year if it idles overnight. Obviously, that number is higher when fuel costs more than $4, as it currently does.

Fortunately, fleets have a variety of options to avoid idling while still accommodating driver creature comforts. But before making those investments, you can take a few simple steps to manage idling. If you don’t already have one, now is the time to establish an idle-reduction policy and communicate that policy to your drivers. Some fleets even incentivize their drivers based on idle numbers. Next, review your engine parameters and set those that impact idle, like idle shut-off timers. Driver buy-in is critical to the success of any idle-reduction program.

The next step is to look at the current idle-reduction technologies on the market. Bunk heaters, also called fuel-fired heaters, can save about 0.7 gallons of fuel an hour when used instead of idling the truck’s main engine. Fleets using auto-start/stop controls can see a 40% to 60% idle fuel reduction because the truck engine runs only part time.

Diesel auxiliary power units (APUs) use about 0.2 gallons of fuel per hour and save 0.6 gallons of fuel per hour when used in place of the truck’s engine. Battery electric APUs (eAPUs) save about 0.8 gallons of fuel per hour when in use. With eAPUs, the engine may run periodically to recharge the unit’s batteries.

Most of these solutions require a capital investment, but fleets typically see payback in six to 24 months. But remember that payback focuses only on hard costs; fleets also need to consider soft costs when evaluating an investment in idle-reduction technologies. Those soft costs primarily revolve around driver safety and comfort, but they can also help fleets fulfill their sustainability promises.

Our 2025 Confidence Report, The Idle-Reduction Playbook, covers the myriad idle-reduction options available to fleets. A best practice is to take a holistic approach to deploying idle reduction strategies. The report found that the most effective solutions combine operational policies, driver engagement, and technology.

Before the temperature drops and the snow starts flying, make sure you have a plan to reduce idling this winter while keeping your drivers warm and safe in their vehicles, no matter the outside temperature.