The Real Cost of Your Car’s Cheap Factory Air Filter

Air Filters: Stock vs. Aftermarket

Far too many consumers judge products solely on the basis of their initial cost, instead of considering their long term economy and benefits. Consider a direct replacement air filter. When comparing a washable and reusable afterm arket air filter at $45 and an original-type paper air filter at $20, consumers that care only about initial cost would choose the paper air filter. Read on and let us show you why this choice is false economy.

According to a recent study by the automotive research firm R.L. Polk & Co., people who buy new cars are now holding on to them for approximately 6 years. Considering that most Americans drive 15,000 or more miles per year, by the end of those 6 years the average car will have traveled almost 100,000 miles. If you change the paper air filter at the 30,000 mile interval recommended by many automobile manufacturers, you will have purchased 3 paper air filters during that time period.

However, browse the internet and you'll see that most automotive experts recommend that a paper air filter be replaced far more often, closer to every 15,000 miles. According to that schedule, that's 6 new paper air filters. Do the math and now the cost of the paper air filter becomes $60 to as much as $120. Suddenly the one-time $45 expense for that aftermarket air filter is looking pretty good.

Cross-section of a typical paper air filter.
Stock Filter Structure
  1. Wood pulp construction.
  2. As dirt builds up air passages are plugged.
  3. Irregular passages filter out dirt.
  4. As fibers swell from moisture or blow-by, airflow decreases.
  5. Turbulent filtered air.

But when you examine the technology behind the aftermarket filter and the original equipment paper filter, you'll find that you'll save even more money with an aftermarket filter. You see, paper air filters are made of wood pulp that is bonded together and formed into pleats. They generally provide adequate filtration, but this comes at the expense of airflow. The passages in a paper air filter must be very small to trap dirt, and these small passages are what restrict flow. Even worse, as the filter becomes dirty, these passages become clogged, further reducing airflow.

When airflow is reduced, the computer controlling the fuel injection system has to try to compensate and adjust the fuel delivery to maintain a combustible air/fuel mixture. The result will be a less than ideal mixture, poor combustion, reduced performance and poor fuel economy.

Most aftermarket air filters, let's use the K&N filter as an example, are constructed from multiple layers of cotton gauze, which are sandwiched between wire mesh that is formed into pleats. Most filters of this type are also treated with a special oil that creates a tackiness throughout the cotton's microscopic strands. The layers of oiled cotton fibers are able to trap dirt particles that are even smaller than the holes in the filter media. Furthermore, dirt is trapped in the depths of the filter, unlike the paper air filter where it collects on the surface. This allows the K&N filter to filter out dirt without restricting airflow. The airflow stays consistent between cleanings, for optimal combustion. The engine operates efficiently, for the best performance and fuel economy.

Aftermarket Filters Review

Most aftermarket air filter manufacturers, including K&N, do not make fuel mileage claims because there are so many variables involved: driving characteristics, weather and road conditions, etc. But let's say your car gets approximately 20 miles per gallon and you pay $3.50 per gallon at the pump. At 100,000 miles you'll have spent about $17,500 for fuel. Even if you only realize another 1/10 of a mile per gallon using an aftermarket filter, you'll have 87 more dollars in your pocket. And if you get as much as another ? mile per gallon it goes up to $427. If you stayed with the paper air filters those savings would have to be added to the "cost" of the filter, so now their real cost would be anywhere from $147 to as much as $547! Now that $45 K&N air filter is looking very, very good.

But there's another cost that goes beyond money, and that is the paper air filter's cost to the environment. Most people, even car buffs, are becoming more conscious of our environment. We're recycling and doing other things to preserve the world for our children. Using an aftermarket air filter helps the environment in 2 ways. As we've demonstrated, using a filter like K&N, Injen or Airaid can save fuel, and when we save fuel we're making better use of our natural resources.

But another less obvious result from using the aftermarket filter is that there will be fewer used paper air filters that end up in the landfill. And if more and more drivers convert to washable and reusable filters, then fewer trees will have to be felled to produce paper air filters. In conclusion, switching to an aftermarket direct replacement air filter is a win, win, win move. The first win is for your wallet, because although the initial cost is higher, an aftermarket filter saves you real dollars over the long haul. The second win is for you and your car. The free-flowing aftermarket filter will give you consistently better performance and fuel mileage than an original style paper air filter. Finally, the last win is for all of us, because the reusable filter makes better use of natural resources and reduces waste.

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