An APU Can Save More than Fuel — TrueNorth

16 Nov.,2022


Truck Electric APU

When you’re on the road, your truck is your home. Whether driving, sleeping, eating, or simply just resting, It’s where you spend the majority of your time. And the quality of that time in your truck makes all the difference - for your comfort, safety, and overall wellbeing.

This goes for the many hours you’re in your truck and not driving, when there are things you want to do that require power without having to keep the engine on, such as utilizing the heat, AC, refrigerator, television, and more. You also want to be prepared for the less expected situations that you might encounter where having electricity can make all the difference in keeping you safe and comfortable - from weather, to road conditions, to truck breakdowns, and more.

This is where an Auxiliary Power Unit (APU) comes into play! Note there are also Electric Power Units (EPUs) that operate similarly, although this post will focus on APUs.

What is an APU?

An APU is the equivalent of a power generator for semi-trucks. It produces energy needed without having to turn on the engine and idle the truck. 

The most common versions consist of a small, 2 cylinder diesel engine and it’s usually mounted on the frame and powers electrical appliances in the cab including lights, air conditioning, TV, microwave, refrigerator, device chargers, and others. The APU is also plumbed into the truck’s cooling system and circulates the coolant to heat the cab and keep the engine warm in cold temperatures to allow for easier starting.

APUs are not necessarily inexpensive, but they are a great investment, as they are beneficial to your wellbeing, your bottom line, and the environment.


Keeping your truck engine on and running is not only expensive, but harmful to the environment. Let’s look at the many benefits APUs offer -

Your Health and Wellbeing

Feeling comfortable and safe on the road benefits your overall health and wellbeing as it allows you to both satisfy and exceed your basic needs. Things like heat to keep warm in colder temperatures and AC to keep cool in the hotter ones require utilizing power. Keeping the refrigerator on to keep dairy and produce, or preparing your meals in the microwave, also require utilizing power. And going beyond simply satisfying your basic needs, power can be a lifeline for entertainment, such as watching TV. 

APUs can also enhance a driver’s quality of sleep. The APU runs much quieter and smoother than the truck’s diesel which constantly rocks and vibrates the cab while the driver tries to sleep. This can help to avoid driver drowsiness, which according to the American Automobile Association (AAA), is the cause of 1 out of every 6 deadly crashes. A good night’s sleep can make all the difference in fending off drowsiness.

Feeling comforted, safe, and rested is so important for your ability to drive. An APU can help you get there.

Your Bottom Line

APUs help you save money on fuel costs, and therefore allow you to take home more profit. Of course there is the investment cost to purchase and install the APU. However, you’ll see that within a short amount of time, that investment pays off and you’ll get to continue to reap the benefits going forward.

This is because APUs burn significantly less fuel than idling a truck engine. For example, according to the US EPA, an APU averages 0.25 gallons per hour while idling the truck’s diesel burns 1.25 gallons per hour. Further, the EPA estimates the average truck idles 2,000 hours per year. At $3.00 per gallon that’s $6,000 per truck per year out the exhaust stack.

We know that some idling can’t be eliminated, but an APU can drastically reduce it. Let’s say you get the idling hours down to 500. You would still save $4,500 worth of fuel in a year.

APUs also can help you avoid some costly repairs. Idling a truck’s engine also fouls the truck’s diesel particulate filter and over time can render the catalytic converter useless, which is an expensive item to replace.

The Environment

Idling your truck contributes to harmful greenhouse gas emissions (GHGs). These get emitted into the air and contribute to global warming. APU diesel units emit far fewer GHGs when it runs, meaning that it’s a much better choice for the environment.

Electric powered APUs are available now that provide zero emissions but to date have a deficiency that will eventually be overcome. Electric units use batteries that are recharged by the truck’s alternator when the engine is running. But the charge isn’t sufficient to last throughout a 34 hour restart. So the engine must be run for a time to recharge the batteries during the restart.

How Much Does an APU Cost?

The price range for new APUs as published by the North American Council for Freight Efficiency indicates new APUs cost from $8,500 to $13,000 US, including installation. The prices vary due to the type of power and the features you require. That may seem excessive for creature comfort, but considering the fuel savings and overall driver wellbeing, the unit’s payback period is short. APUs can be installed either aftermarket or on a new build. 

Of course, every good idea comes with a downside, these days. A diesel powered APU requires regular oil and filter changes, as well as annual maintenance inspections to keep them at peak performance. This results in a longer payback period, but when the price of fuel goes up so do your fuel savings and that shortens your payback time.

If you’ve ever been stuck with a broken down truck in cold or triple digit heat, you’ll truly appreciate your new APU. And let’s not forget highway closures due to crashes or bad weather. Take the I-95 backup a few days ago on January 3, 2022. Idling your truck may not be an option, especially if you had planned to fuel up at your favorite truck stop up the road.

Whenever you’re stopped and in your truck, such as with detention times, having no-touch freight loaded or unloaded you can use your APU to avoid idling the truck and be in comfort while you save fuel. An APU can allow you to make money instead of wasting it.

A summary of the Advantages and Disadvantages

An APU provides the following advantages:

  • Safety and comfort from extreme temperatures, hot or cold

  • Enhanced quality of sleep for drivers, reducing dangerous drowsy driving

  • Fuel savings anytime you’re in the cab and not idling the truck diesel

  • Reduction of GHG emissions to lessen the effects of climate change

  • Reduction of costly repairs to the truck’s emission control systems

  • Powers the electronic features in the cab

  • Circulates the truck’s coolant to warm the engine during cold weather starts

And a few disadvantages:

  • Initial purchase and installation cost

  • Ongoing maintenance costs

As an Owner-Operator dealing with high fuel costs, varying weather and road conditions, and risk of breakdowns, the advantages of having an APU certainly outweigh the disadvantages. It’s worth looking into this type of investment today - for both you and the environment!