The Importance of Calculating DEF Consumption


Many truck operators have engines with exhausts with selective catalytic reduction after-treatment systems and have claimed their fuel use is as good or close to what the manufacturers claim. You must also factor in the diesel exhaust fluid that’s used in the process. Injecting DEF into your exhaust helps to neutralize nitrogen and oxides, or better known as NOx. This is the action from the SCR which is used by many diesel manufacturers. DEF, much like fuel, is used every day, and for all intents and purposes, should be accounted for in claims or economic reports. Your best bet is using a DEF usage calculator.

DEF Consumption

The thing to figure out is how much DEF are you using. Manufacturers using SCR in over road operations suggest a rate of around 3%, which roughly equals out to about 3 gallons for every 100 gallons of fuel. Some long-haul carriers have seen a 10% improvement in fuel consumption when running identical routes. This is comparing SCR units to older models. There have also been some disappointing reports, claiming poorer fuel economy. The expert opinion is that performance comes down to factors such as road, route, and service. It’s recommended that drivers refill DEF at least once in every third time they refill their tanks.

Climate Consideration

One of the challenges facing truck stops is what to do in colder climates. Having a DEF dispenser in an area with low temperatures is an issue because DEF becomes slush at 28 degrees and will freeze at 11 degrees. This is a factor that must be considered in your overall DEF use, depending on your route. However, there are storage solutions available for both large and small-scale fleets, commercial locations, and retail facilities. Insulated bulk storage containers can help install contaminant-free DEF in extreme weather conditions. The containers ensure the approximate shelf life of DEF does not get hindered.


With the cost of DEF slowly coming down from where it was when it first hit the market, it’s also becoming more attractive. This doesn’t mean that DEF’s price isn’t all over the place, depending on your geographic area and retailer. When and if DEF becomes the same price as diesel fuel, the urea injection economics will merely be about subtracting DEF cost from the truck’s fuel improvement.

If you’re interested in finding out more about DEF consumption or getting a diesel exhaust fluid calculator, contact the professionals at Blue Sky Diesel Exhaust Fluid for more info.