Fuel-Operated / Diesel-Fired Heaters

Fuel-operated or diesel-fired heaters use diesel fuel to provide heat to the sleeper cab (bunk or air heaters) or to provide heat to the truck engine (water or coolant heaters). Both types of heaters can operate when the truck’s engine is off, therefore avoiding idling. However, these systems do not provide any cooling or AC electric power to the cab. There are two types of fuel-operated/diesel-fired heaters:

  • Fuel-operated air heaters
  • Fuel-operated coolant heaters

Benefits

Relatively inexpensive to purchase and maintain

Generally burn less than 0.1 gallons of fuel per hour. An idling diesel engine will consume between 0.6 to 1 gallon of fuel per hour. On average a fuel-operated air heater will use approximately a gallon of fuel during a 24-hour period

Install easily usually under or behind the sleeper, do not require frame free space. Available as factory installed options from all truck OEMs. Integrate with other idle-reduction technologies, and are often sold in combination with other idle-reduction technologies

They operate very quietly and produce minimal emissions

Relatively inexpensive to purchase and maintain

Eliminate difficult truck engine cold starts. Pre-warmed engines deliver cab heat and defrost windows more quickly upon engine start up, and warm engines produce fewer engine emissions at start-up

Provide higher heating capacity than engine block heaters and do not requite AC power electrical connections

Can be programmed for remote start-up without driver interface

Available as a factory-installed options from all truck OEMs

Challenges

Only provide bunk heat and do not meet the other driver needs — air conditioning or AC power for hotel loads — nor do they provide engine pre-heat

Use the truck’s main engine batteries for their power, and therefore can drain those batteries over long periods of use

Emit some exhaust as they burn fuel

Only provide bunk heat and do not meet the other driver needs — air conditioning or AC power for hotel loads — nor do they provide engine pre-heat

Use the truck’s main engine batteries for their power, and therefore can drain those batteries over long periods of use

Emit some exhaust as they burn fuel

Fleet Survey Results

  • If a fleet does not use APUs, their idle percent tends to be in the 30% to 50% range
  • If a fleet uses APUs, idle percent is in the single digits to 20%
  • Fleets seem to be split on diesel APUs vs. battery HVAC systems with some fleets using both (but not on a single vehicle)
  • Use of auto start-stop systems is increasing
  • Almost everyone uses diesel fired heaters
  • Most fleets are looking for positive ROI, but most of them also think there is significant value in driver retention and hiring

Decision-Making Tools

Our team produced top-line tools to assist fleets in making their idle-reduction technology choice:

  • The confidence matrix summarizes the study findings and indicates NACFE’s confidence in the various idle-reduction technology solutions.
  • The Payback Calculator allows fleets to estimate the payback in months for various idle-technology solutions. Fleets input data into the form and the calculator uses the data along with the information gathered by the study team to quantify and benefits and consequences likely to be experienced by the fleet in terms of upfront costs and year-over-year costs.

In addition the report contains challenges and changes charts for each of the anchor technologies. The charts can be found in section 9 of the report.

Manufacturers: Fuel-fired Air Heaters

Manufacturers: Fuel-fired Coolant Heaters

Conclusions

As a result of research and interviews the study team reached the following conclusions concerning idle reduction in the sleeper cab market:

  1. Reducing idle is good for the environment, saves fuel and improves a fleet’s “green image.
  2. A 10% reduction in annualized idle percentage is worth about 1% in fuel economy that results in a $500 to $700 annual savings assuming 100,000 miles a year and diesel at $3 a gallon.
  3. Driver hiring, comfort and retention are mentioned in almost every conversation about idle-reduction technologies. Some have said that offering a good solution is a requirement for hiring and retaining drivers.
  4. There is no “one size fits all” solution to idle reduction.
  5. Drivers are still a very important part (If not the most important part) of successful management of idle times.
  6. Depending on “shore power” (outside electrical connection) to be available is not a reasonable idle-reduction solution for most fleets as the number of electrified parking spaces is extremely small compared to the number of trucks that need to be parked at any given time.
  7. Most suppliers of idle-reduction technologies mention that their solution helps minimize maintenance costs, particularly in the vehicle’s aftertreatment system. However, we have been unable to uncover any data that actually substantiates those claims.
  8. The answer to the question of the resale value of trucks equipped with idle-reduction technology is unclear.
  9. Maintenance of the vehicle’s battery connections and electrical systems is critical to getting the best performance out of idle-reduction technologies.