Can a Dirty Cabin Air Filter Affect the Car's Heater?

by Chris Gilliland

Many car owners neglect their cabin air filters when maintaining their rides. This is mostly due to the fact that most people don't even know this unobtrusive filter exists as it usually doesn't come to mind while changing spark plugs and engine oil. However, a dirty cabin filter can drastically reduce the performance of your car's air conditioning and heating system.

How Cabin Air Filters Work

Just as your home's air conditioning system relies on filters, so does your car's. As its name implies, a cabin air filter prevents dust, dirt and road debris from entering into the car's cabin, where you and your passengers sit. As the outside air is drawn into the air conditioning, it passes through the cabin filter's pleated media, trapping pollen and dirt before it can accumulate within the air conditioning duct work. Without a cabin air filter, the dust that doesn't settle within the system will be blown directly at the car's occupants.

Cabin Air Filter Construction

A cabin air filter can look almost exactly like the air filter used by your car's engine. The filter is usually composed of a paper element that is folded into pleats and surrounded by a rubberized gasket. In many cases, the paper element is white to help you determine when the filter is dirty. As a rule of thumb, if the filter looks dirty, it is. Because the filter is made from paper, it cannot be washed, leaving replacement as the best option.

The Effects of a Dirty Cabin Air Filter

The pores in a cabin air filter's paper element are designed to be small enough to allow air to pass through, while trapping larger dust particles. Over time, the pores become clogged and reduce air flow. This, in turn, forces the air conditioning and heating system to work harder to produce the same results. Imagine, if you will, that you are trying to breathe through a handkerchief; you can breathe fairly well. Now, add two more handkerchiefs to that to simulate the accumulation of dirt, and suddenly it becomes much more difficult to breathe. This is what happens in your car. In winter, the reduced intake of air decreases the amount of warm air the heater is capable of blowing into the cabin. The same holds true for the air conditioner in the summer months.

The Benefits of a Clean Cabin Air Filter

Replacing your cabin air filter every six months or 15,000 miles can be very beneficial to the performance of your car's air conditioner and heater. Additionally, the quality of the air being introduced into the cabin will improve by removing more dust and pollen that can cause allergies, instead of adding to the mess. Lingering odors in the interior can also be virtually eliminated with a new filter, since the odors have settled into the old filter over time.

About the Author

An avid motorcyclist, Chris Gilliland has immersed himself into the two-wheeled world while balancing work life and raising three daughters. When he is not managing the parts department of a local, multi-line motorcycle dealership, Gilliland can often be found riding, writing or working on his motorcycle blog, Wingman's Garage.

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