There are many products on the market that claim to improve fuel economy. Some work as claimed, and some work, but not as well as claimed. Some only work in specific conditions or on specific equipment.
Whatever the claim, it is up to you to do your research to see if a product or service is right for you.
We all, I hope, purchase the equipment that will best suit our operation. With that said, there are situations where you cannot get it perfect. Aftermarket products can help. Aerodynamic devices can also help, such as trailers, tractors, roof fairings, side skirts, and wheel covers to name a few. The thing is, in my opinion, this equipment needs to pay for itself.
I've heard that if a product pays for itself within six months, it's a no brainer, get it done. Up to a year, probably, but you need to think about it. Over a year, it will lean into the resale upsell to recoup the initial expense.
Let's do an example calculation. There is a product you’re interested in that is proven to improve fuel economy. Let’s say it costs $500. If the manufacturer is correct, you will gain 0.5 mpg (½ mpg). Assume a fuel cost of $3.00 per gallon. In a straight truck, that will raise us from 11 mpg to 11.5 mpg. At 11 mpg, ($3.00 divided by 11) that's .2727 cents per mile (CPM) for fuel, 11.5 is .2608 CPM, a net gain of approximately (rounding for easy calculating ) 0.0125 CPM. So $500 divided by 0.0125 is 40,000 miles, or roughly three or four months of driving. After that, it’s 0.0125 CPM extra profit, which could mean an extra $500 or more a year.
When idling for temperature control, you should service the truck engine by hours instead of miles, depending on the idle time that could be twice as often as a truck that doesn't idle. To calculate the benefit of idle reduction devices you use a different calculation, which can be seen here: https://www.griffinarmor.com/idle-reduction/idle-reduction-calculator.php .
APU's have expenses as well, but fuel and services are much less than the wear and tear on the truck engine. A $12,000 APU needs to be added to the resale value or transferred to a different truck, spreading the purchase price over many thousands of miles.
You can apply this to anything you purchase for the truck. If you average 120,000 miles per year, you can divide your purchase cost by the number of miles you drove. Some things, I think, have a convenience value on top of quantifiable value, like a refrigerator. It will save you on food expenses, and that cannot be measured by miles, but it could be measured by a number of days you do not eat in a cafe/restaurant. A $15 restaurant meal vs. a $6 in-cab meal will pay for a fridge quickly.
All these savings can be saved, added up, and could pay off some bills or make a nice vacation fund. There is an initial expense for everything, but if the return on investment (ROI) is quick, it makes you more efficient or comfortable, do some calculations and make an informed decision.
Until next time, think about it.