Many customers have asked me why their fuel mileage drops during the fall and winter months. The answer is two-fold.
Number one: Your driving habits change considerably during colder months. Consider the fact that you are allowing your vehicle to warm up before driving. We all want to be comfortable. Even though our car isn't moving, the engine is running and consuming fuel. We also tend to drive much slower during the inclement periods of the year. When it snows we move along at a snails' pace. Sometimes when we drive in snow it takes twice as long to get where we are going. These changes make a significant difference in mileage. Number two: All refiners of gasoline, to be sold in the northern states, put additives in their fuels. Some are mere stabalizers and some are antigelling agents. In colder climates fuel will become thicker and does not flow through the fuel system as required. The additives are necessary for proper functioning. These additive fuels, aka winter blends, totally destroy gas mileage. I've seen as much as 15% drops in mileage.
In the last five years many manufacturers have been able to increase the fuel mileage of many models by further decreasing weight and making their bodies more streamlined. The basic engine has not changed much. The lofty goal of fifty mile per gallon vehicles is a hard one to reach. Many models have already peaked as far as mileage is concerned.
Even hybrid vehicles, that utilize lithium battery technology to accomplish better gas mileage, have the drawback of needing to be charged. The average cost of charging said batteries to drive forty miles is about $2.50. To reach a federally mandated goal of fifty miles per gallon, new technologies outside of gasoline will need to be devised. The internal combustion engine will never be more than fifty percent efficient. Right now it is around thirty eight percent efficient.