How Much Savings Can I Get From a Truck APU?

Adding an auxiliary power unit, or APU, to your truck is an investment, a large one at that. Typical APU prices can range anywhere between five-thousand dollars up to twelve-thousand dollars per unit. If you are a fleet owner and are looking to outfit multiple trucks at a time this expense can add up quickly. Or, even if you are just a sole owner-operator a twelve-thousand dollar expense is nothing to sneeze at.

So, the question now is adding an APU to your truck really worth it? What kind of savings can you expect? How long before these savings end up paying for the initial investment? These are all important factors to consider before purchasing an APU and in this article we will take an in-depth look at these points and more. Let’s dive in and take a look:

What Can You Save?

The first thing we need to look at here is exactly what you can save by adding an auxiliary power unit to your truck or to your fleet. The most obvious savings is fuel. If you do not have an APU installed and your driver is either sitting at a dock for multiple hours at a time or they are staying overnight then they will most likely end up idling their truck for either heating, cooling, or just general electricity for their appliances or electronics.

This idling eats up fuel. As you all know fuel is by far the biggest expense when it comes to trucking. So, by spending multiple hours a day idling you are throwing that fuel expense right out the window. If you had an APU installed this fuel expense would be cut significantly. Along with the savings from fuel you also need to consider that in many states idling for a long period of time is illegal. If caught you could face heavy fines and other consequences. Having an APU installed and running saves you from these possible fines.

Again, if we look at idling the engine for extended periods of time we also learn that idling is much tougher on the engine then standard driving. Over time constant idling will end up causing your truck more maintenance needs. Things that were going to need to be done perhaps a year down the road may show up much earlier with constant idling. These repair expenses can add up quickly. Along with the extra engine maintenance the idling can also have adverse effects on your diesel particulate filter. Soot and other containments can accumulate due to idling which will result in your DPF needing cleaned much earlier then normal. Again, this is a large expense that comes directly from idling. If you had an APU installed you could avoid all of this and push those maintenance needs further down the road.

Another point to recognize here is that if your truck or your fleet does NOT have an APU installed you could also be looking at a problem of driver retention. The APU is a comfort item. Many drivers swear by them and many drivers will not drive trucks without them. Could you sleep in your bed in the summer without air conditioning? Then how can you expect a trucker to do so? If you are a recruiter or small fleet owner you may actually see your offers declined due to your trucks not having APUs. I have even seen some examples where drivers take a small pay cut just to go with the company that offers APUs. The cost of replacing and hiring drivers is difficult to measure but it is there and should be considered when looking at APUs.

The last point to mention most likely doesn’t impact a lot of you but some overnight drivers will check into a nearby hotel room instead of sleeping in their cab. This holds especially true in warm or cold climates when their truck has no APU. By adding an APU you are able to prevent these hotel charges as the driver will be more then comfortable in their own truck rather then checking into a hotel room.

How Much Can I Save?

This is a difficult question to answer as each situation, each driver, and each fleet owner are different. We all drive different routes, make different stops, drive different vehicles, and experience different situations. This is why it is so difficult to gauge. With all of that in mind, what I can give you are some basic guidelines and facts when it comes to APUs. Use this information to determine exactly what fits right for you.

Throughout my research I have found that an auxiliary power unit will end up saving anywhere between seventy-five percent to eight-five percent in fuel usage when compared to idling. So, for an example let us say that idling for one hour consumes about one gallon of fuel. Your truck idles for eight hours a night five days as week. That equals four hours per week and about one-hundred and sixty hours a month. That equates to one-hundred and sixty gallons of fuel spent during that month idling.

One-hundred and sixty gallons of fuel times whatever fuel cost at the time. For our example let’s call it three dollars a gallon for diesel. Three dollars times the one-hundred and sixty equals four-hundred and eighty dollars total expense per month. Now here comes the fun part. Let’s shrink that number by eighty percent to get a new fuel cost if you had an APU installed. four-hundred and eighty dollars per month less eighty percent equals ninety-six dollars. That is a difference of three-hundred and eighty-four dollars per month, or almost five-thousand dollars per year.

Now remember, that five-thousand dollars per year is a complete estimate. What if you were idling for two-hundred hours a month instead of one-hundred and sixty? What if the cost of diesel fuel went up, or down, quite a bit? All of these factors can impact your savings when going with an APU. To help answer some of these questions and to also give you a bit more input a few APU manufacturers have actually created their own savings calculators.

One such example is from Thermo King. The link to this calculator can be found by clicking here. I walked through a set of my own data and ended up saving around nine-hundred a month or a little less then eleven-thousand a month. The cost for a new Thermo King is about twelve-thousand dollars so you more or less break even after about a year after install. The other company that has a calculator is Rigmaster. Their calculator can be found by clicking here. The results were mostly the same with a savings of around nine-hundred a month and a yearly total of around ten-thousand dollars per month.


As you can see folks determining the savings from an APU can be quite difficult due to all of the variables and factors that exist for every driver. It is a hard number to ascertain but based on the information I provided in this article along with the links to Thermo King and Rigmaster’s APU savings calculators you should be able to get an idea on exactly how much you could save per month and year by installing an APU.

I hope this article was helpful and thanks for reading folks,

Alec Johnson

You may also like