Reducing idle time saves fuel, no doubt about that. But it does require the co-operation of your drivers. Drivers are much more likely to turn the truck off when they stop if they can still stay warm in the winter and cool in the summer.

Throw in strict no-idle laws in some states and municipalities, and you've got added impetus to invest in idle-reducing technologies. Products such as auxiliary power units have long been popular with owner-operators. But more fleets have become interested in the technology, prodded by regulations and high fuel prices.

"Fleets that are tracking idling time are really driving our technology right now," says Bret Reinhardt, president of Sun Power Technologies of Carmel, Ind. "You can take federal and state regulations out of the mix," he says. Fuel savings, and to some extent driver retention, are the things prompting trucking companies to investigate idle-reduction technologies.

"With fuel prices the way they are now, the math is very compelling," says Eduardo Andrade, manager of Carrier's APU product line. "We find nowadays that folks are far more sophisticated when it comes to understanding their operations. Most of them know how much fuel their rigs are consuming at idle. You are talking about saving .8 of a gallon to a gallon for every hour you exchange from the big rig engine to the APU engine."

When Klaus Holze got started in the business in 2000, "it was usually the owner-operator that was buying, because he had a direct relationship with his fuel budget," says the national sales manager for SCS Frigette, Forth Worth. "A fleet owner has an entirely different circumstance. When fuel was relatively inexpensive in those days, it was difficult to justify to a fleet a payback of two years. Now that fuel prices have escalated, the payback period has shortened up and fleets are taking notice," especially small- and medium-sized fleets.

Even larger fleets are taking an interest. "If we continue to see oil prices at lofty levels, the mathematics are too powerful to sidestep," Holze says. "Even the large fleets are now all tire-kicking. Some are making the leap, but a great many are calling for information and test units."

Many have liked what they've seen, with sales of devices such as auxiliary power units increasing dramatically in recent years.

Will Watson, vice president of sales for Auxiliary Power Dynamics, Sparks, Nev., says demand for APUs remains strong. In fact, he says, the growth rate in APU sales could be "two or three times" more this year than last.

Other APU manufacturers have seen similar trends. "Our customers are about 50-50 fleets and owner-operators," says Amy Egerter, marketing manager for Rigmaster Power Corp., Toronto. "The owner-operators were first. They are the ones that see immediate savings with an APU."

But with state and local laws limiting idling and a push by the U.S. Environmental Protection Agency to decrease truck idling, more fleets are spec'ing APUs. Programs such as the EPA's SmartWay Transportation Partnerships provide grants to states and air districts to promote anti-idling programs and technologies. These programs can include low-interest financing and in some cases, funding for buying technologies such as APUs, inverter/chargers, electric air conditioners and heaters. "Fleets have been coming on board en masse," Egerter says. "These programs are doing a lot to bring fleets in."


Fleets have plenty to choose from when searching for technologies to reduce idling. From APUs to electric-powered A/C units and fuel-fired heaters, there are products designed to meet most applications.

Auxiliary power units can offer the most features: heating, air conditioning, engine warming, battery charging and plenty of power for convenience items such as TVs, computers and coffee makers. But APUs are relatively expensive and installation can take up to 15 hours. Plus, they still burn fuel – about a pint per hour compared to a gallon or so for a big rig engine. And, as small engines, they require routine maintenance.

Alternatives are electrical- powered air conditioning systems and/or fuel-fired heaters.

"The largest selling point for our system is there is no fuel consumption," says Sun Power's Reinhardt. "There is no ongoing small engine maintenance. There is no oil to change, belts or hoses to service and the install time for our unit is about one-fifth the time required to install an APU."

These systems can either use the truck's existing batteries and alternator or come with their own battery packs and an upgraded alternator. The systems typically use their own vent work and blower motors to move heated or cooled air around the sleeper compartment.

The Sun Power Eco-Air 12-volt system is a completely self-contained unit, weighing in at about 430 pounds. It uses its own battery system to run an electric air conditioner. The battery box is installed on the truck's frame rails while a compressor/condenser unit is mounted outside the rear sleeper wall. The evaporator coil hangs inside the truck. The system's batteries are recharged by the truck's alternator when the truck is moving. A charge controller limits the amount of power the unit draws from the alternator and protects against over-charging the system's batteries. Those batteries can serve as backup cranking batteries when needed.

The unit delivers 10,000 Btu of cooling capacity for eight to 12 hours on a single charge. The system's batteries also supply 12- volt DC power to run diesel-fired heaters, such as those from Webasto or Espar, and can supply 12-volt power for "hotel" loads inside the cab. Depending on options, the system costs between $6,100 and $9,000 and can be installed in about four hours. For more information, go to

Dometic Environmental Corp., Pompano Beach, Fla., recently introduced an all-electric auxiliary air-conditioning unit that runs off the truck's batteries. The package includes a 7,000- or 10,000-Btu split or self-contained air-conditioning system, DC-AC inverter, high-capacity alternator and optional shore power pass-through. The inverter converts DC power from the truck's batteries into 120-volt AC power, which drives the A/C. Dometic's alternator replaces the truck's existing engine-mounted alternator and charges the batteries when the truck is operating. If the shore power option is specified, that power can also charge the truck batteries and run the A/C unit.

The split system includes a condenser/fan mounted outside the truck and an evaporator/compressor/blower unit mounted inside the truck. The air conditioning units can also provide electric heat or be teamed with a fuel-fired heater.

Dometic has also teamed with Temco Metal Products to offer a product called Idle Solutions, which includes a Dometic heater-air conditioning system and a 120-volt, 7,200-watt Temco genset. The genset powers the HVAC system and provides household current for the driver's creature comforts. On the web:

Webasto Product North America, Fenton, Mich., sells engine-off heaters and air-conditioning units. The company's fuel-fired heaters keep truck cabs and engines warm in the winter. The Air Top 2000 and Air Top 3500 air heater units deliver 7,000 and 12,000 Btu, respectively, of heating power and provide 10 to 20 hours of heating per gallon of fuel. The compact units mount under the bunk in the truck's sleeper compartment.

Webasto also offers the BlueCool cooling system, a bunk-cooling system that can provide up to 10 hours of cooling operation while drawing only 3.5 to 6.5 amps from the truck's batteries. The unit uses no fuel, but a cold storage cell that is charged while the truck is being driven. When the truck stops, the truck's engine can be switched off and the BlueCool unit will keep the cab comfortable. The unit uses power from the truck's batteries to move cold coolant between the storage unit and a heat exchanger and to power four air distribution fans. The company says the unit can cool a truck for up to nine hours before needing to be recharged. For more information,

The Bergstrom NITE (No-Idle Thermal Environment) System is an electrical system that cools the sleeper compartment. The system includes a rechargeable battery system, air-conditioning unit and auxiliary heater from Espar Heater Systems. The air-conditioning system draws no power from the truck's batteries, but uses a rechargeable deep-cycle battery system that can deliver cooling for up to 10 hours between charges. All the components run on 12-volt DC power, so no power inverter is required. The air-heating system uses about 0.06 of a gallon of diesel fuel per hour.

The unit can be installed on any truck, the company says. For more information, go to

Espar Heater Systems makes fuel-fired heating systems to keep the truck cab warm and to pre-heat the truck engine for improved cold-weather starting, and is offered as an option from most truck OEMs. The company's sleeper compartment heaters cycle through four heat levels to maintain the desired temperature set by the operator.

The unit can be installed easily in a truck's luggage or tool compartment in most sleeper cabs and can run for about 20 hours on a gallon of diesel fuel. They system requires no electrical plug-ins. Visit

With most electrical systems, the batteries need to be charged periodically. "The drawback of any battery-powered system, if you have an extended stay of more than a day, you are forced to run the truck to charge the batteries," says Sun Power's Reinhardt. That's one reason shore power is becoming more and more popular. "APUs can run for days, and if you can find shore power, systems like ours can also run for days."

Xantrex Technology's inverter/charger system can provide easy access to shore power. It converts stored battery power into AC power to run appliances such as coffee makers, refrigerators, microwaves, etc. When shore power is available, truckers simply plug in and the system uses shore electricity to power their appliances and recharge the truck's batteries. Xantrex's inverter/charger wires into the truck's existing electrical system, connecting directly to the battery bank. It converts the batteries' DC power into AC power. When plugged into shore power, the unit uses the AC power from the shore connection. For more, go to:


While many observers see purely electrical systems as the wave of the future, APUs are a better fit today for some applications.

"The future is possibly going electric," says Carrier's Andrade. "But today, there are limitations as to what you can do as far as energy storage. Battery life, weight, the amount of energy stored, doesn't quite reach the expectations of some operators."

Auxiliary power units come in a variety of configurations, with units featuring small diesel engines generally falling into one of two types: stand-alone or integrated systems. Stand-alone systems essentially provide backups for the truck's components and typically include a small engine, an alternator/generator to produce electrical power, an air-conditioning condenser and compressor, heater core and power outlets.

Stand-alone systems typically feature three or four components: The main unit, including the engine, radiator, alternator/generator, A/C compressor and often the A/C condenser, is mounted on the truck's side rails. A heater/air conditioner unit is usually mounted under the sleeper bunk. A control panel is mounted in the cab or sleeper allowing the driver to control the unit without exiting the truck.

Integrated systems tie into much of the truck's existing systems. The Willis APU from Auxiliary Power Dynamics is one such product. "We use everything on the truck except the air-conditioner compressor," Watson says. "Like a lot of makers, we use the truck's coolant and recirculate the coolant throughout the truck to provide heat to the engine and heat to the truck," he says. "We go through the truck's condenser; we use the truck's expansion valve." The system makes use of the truck's HVAC system so the warm air generated comes out the truck's regular vents.

This design does not take up space underneath the sleeper bunk. Other features include a 150-amp alternator, solid-state electronic control, a 3-cylinder 18.8 horsepower Kubota engine, and an optional 1,750 watts of continuous household power using a Xantrex inverter and fully wired power outlets. On the web at

Carrier's ComfortPro is a hybrid system. It can work off of shore power, or use its diesel-fueled Kubota engine to generate power. One of the key design differences in the Carrier system is the "hybrid diesel electric-approach," Andrade says. "Instead of a belt-driven or open drive automotive style compressor, we have the APU engine driving a 4-kW AC generator, which in turn drives a sealed compressor, similar to what you have in your refrigerator." This unit is mounted inside the sleeper with an AC motor-driven blower. The split design "allows us to remove certain components from the harsh environment of the frame rail and place them inside the comfortable ride and protected environment of the sleeper."

In this system, the alternator is dedicated to charging the truck's batteries. On the web at

A new entrant into the North American APU market is the Italian engine maker Lombardini of Duluth, Ga. The company will begin selling its APUs in the U.S. next year. According to product manager Alessandro Sacchi, the EcoWind brand APUs are stand-alone designs featuring a genset powered by a Lombardini engine, evaporator, condenser, battery charger and power receptacles to provide air conditioning and cooling. Find out more at

Blackrock Systems, Reno, Nev., offers the Blackrock APU with either a 2-cylinder or 3-cylinder Yanmar diesel engine. The 3-cylinder engine is designed for large sleepers to provide more A/C and electrical output. The engine provides the power to run the A/C compressor, 120-volt generator and a 12-volt DC alternator. The Blackrock features heating, cooling, AC power, a three-year/4,000-hour limited warranty on the engine and a two-year/4,000-hour limited warranty on the APU. For more information, go to

Double Eagle Industries, a specialty sleeper manufacturer in Shipshewana, Ind., makes the Gen-Pac APU, which features a 3-cylinder Kubota diesel and Fidelity alternator that is direct driven by the Kubota. The system features interior electrical receptacles, remote start in the sleeper and an optional Kool-Pac that provides enough cooling for an 80-inch sleeper. Visit

Relatively new in the truck market, Kohler Power Products of Kohler, Wis., began production of its APU in April. The 5-kilowatt unit features a compact design and weighs just under 350 pounds. It's a self-contained unit featuring an air-cooled engine. The unit delivers 120-volt AC power and 50-amp DC power. It is also designed with a direct-drive alternator, eliminating alternator belts. The unit mounts on the truck's side rail and comes with Kohler's Advanced Digital Controller as standard equipment. The unit features battery charging, heating and cooling. For more information, go to

The Cummins ComfortGuard APU System represents the engine maker's first complete auxiliary power unit system for over-the-road trucks. The system combines the company's Onan generator with HVAC components. The system features quick disconnects and pre-charged A/C lines to aid installation. The system can be installed and serviced throughout the U.S. and Canada by Cummins dealers and distributors.

The ComfortGuard's A/C system fits under the sleeper bunk. An electric heater provides heat for cool nights. A home-like thermostat controls the system, which can be set to automatically start based on time of day or the thermostat setting. A 2-cylinder engine provides power for the unit. A Cummins alternator puts out 4,000 watts, 60 Hz AC current to run electrical appliances and 40 amps of 12-volt DC current for battery charging. On the web at

The Pony Pack 200, from Pony Pack of Albuquerque, provides electric power, heating and cooling with a 2-cylinder, 10-horsepower Kubota engine, Ford 110-amp alternator, Ford air-conditioning compressor, Modine radiator and AC condenser. On the web:

Rigmaster's APUs can be ordered with either a 14-horsepower Caterpillar or Perkins engine. The system features a 6--kW generator and 60-amp alternator that delivers battery charging power and 120 volts A/C power. It heats or cools the cab and can power an existing engine-block heater. A cab-mounted control panel allows drivers to set temperature and autostart settings from the comfort of the cab.

Rigmaster says its current models can burn both biodiesel and ultra low sulfur fuel. For more information,

SCS Frigette's hybrid auxiliary power unit features a 3.5--kW generator, air-conditioning compressor and a 7-horsepower Kubota single-cylinder engine.

The system provides heat and air conditioning while charging the truck batteries. It also generates 3,500 watts of 110-volt electricity for on-board appliances. The unit's engine burns about .1 gallon per hour. A 60-amp battery charger is included. See more on the web at

Thermo King's TriPac APU provides engine preheating, battery charging, climate control and electrical power to the cab. It features a microprocessor controller so the driver can easily set truck cab cooling and heating levels.

The truck battery charging system features automatic voltage sensing and the unit supplies 120 volt electrical power for on-board appliances, computers or other equipment. On the web at


Most APU makers say the devices can pay for themselves in 18 to 20 months, based on the current price of fuel. Prices of the systems vary greatly depending upon the system and options, but run from around $7,000 to more than $10,000. Plus, installation can take eight to 15 hours. For truck fleets, paying for several hundred, or even several thousand, units represents a huge outlay of cash. Electrical systems are somewhat less expensive and usually do not require as much install time. Still, these units can run upward of $6,000, depending upon options.

"Our model is very conservative and shows a payback in 18 to 20 months," says Sun Power Systems' Reinhardt, "although one of our customers plugged in their true fuel consumption costs and saved maintenance costs and they came back with an ROI of about 11 months." He noted that some fleets look only at fuel savings when looking at ROI, while others take into account the reduced maintenance and other savings from running the engines less.

Reinhardt reports that most of their customers, who previously saw idling in the upper 30 percent to lower 40 percent range, have been able to drop that to the 5 percent to 10 percent range. "With shore power, we think we can get that number lower, but some idle time you just can't get around."

With fuel at nearly $3 per gallon, Carrier's Andrade says a fleet can save $30,000 to $40,000 over the five years of a vehicle's life. And the savings are a direct result of less idle time. What fleets actually see in reduced idle time "varies dramatically," he says. "It depends upon how a fleet manages their drivers." But it's not uncommon for a fleet with idle times in the 30 percent to 40 percent range to see idle reduced to 7 percent or 8 percent after installing a no-idle system.

"It will never be zero, of course," Andrade says. "There's a certain amount of idling that will always be there. We typically tell customers to expect about 10 percent idle time. But folks that are monitoring, tracking and working with their drivers can see 7 percent to 8 percent idle time."

Fleets can finance the cost of no-idle technology with the price of a new vehicle, and realize almost instant cash flow improvements, says APD's Watson. "If you structure the financing correctly, the fleet can actually increase the cash flow per truck in the first month," he says, noting that the savings in fuel each month will more than offset the finance payment.

Carrier's Andrade agrees. "If you look at a fleet that is going to finance these, you are going to be cash flow positive from month one. If you look at it from a cash flow basis, the fuel and the maintenance savings are going to do the job."

While shutting off a truck's engine during idling is meant to save fuel and help reduce emissions, even the small engines in an APU can't escape the regulators' oversight. Federal guidelines require APUs to meet off-road diesel engine emission standards. In California, however, the state's Air Resources Board has set standards that would require APU engines to meet the same standards as 2007-model year engines, including having an aftertreatment device on the exhaust.

"We aren't concerned about the regulations, but change causes disruption," Andrade says. "We see it as another aspect of doing business. California is really pushing the envelope when it comes to some of the requirements that will kick in in 2008. They will impact our APUs. It is certainly disruptive in the short run. In the long run, it allows opportunity for differentiation – it adds technological value to the product and allows companies with more resources to develop innovative technology to come to the forefront. We see it as more of an opportunity than anything else."

According to SCS Frigette's Holze, if you drive a 2006-model truck with a 2006-model-year engine, you can run your APU in California, no problem. If you buy a 2007 model truck with a 2006-model-year engine, you can run an APU. But if you buy a 2007 or later model truck with a 2007 or later model year engine, the APU must meet the same emissions standards.

Rigmaster's Egerter says APU makers are working to develop some sort of aftertreatment that will satisfy California regulations, but it will probably increase the cost of APUs operating in the state. California's rule does not go into full effect until 2008.


Fleets have other options to reduce idle time and keep drivers happy. The IdleAire system provides HVAC, Internet access, movies, TV and phone service. without any extra equipment on the trucks.

TravelCenters of America recently entered into an agreement with IdleAire to install its system in TA truckstops nationwide. The systems can already be found at other truckstop locations, including many Petros.

According to Peter Green, TA senior vice president of development, "By offering this alternative to idling at our travel centers, we help reduce diesel fuel consumption and emission into the atmosphere. We also help our fleet and independent drivers reduce their own fuel costs and provide them with in-cab heating and cooling, phone service, Internet access and entertainment options."

With the IdleAire system, fleets either sign up for subscriptions or drivers can buy individual subscriptions. They park in a designated place and attach a flexible duct to the passenger-side truck window. The duct provides HVAC and includes a control module, TV screen and phone and computer hookups.

Lower maintenance costs, regulatory pressure and driver retention are all good reasons for a fleet to investigate idle-reduction technologies. But perhaps the best reason of all is three bucks a gallon for diesel fuel.