Being comfortable in your vehicle is key. You want clean, climate-controlled air circulating around you, no matter how dusty, cold, or hot it is outside. You depend on your car or truck’s cabin HVAC system to do this. How does this system get clean, temperature-controlled air to you from the outdoors, even in sandy or dusty climates?

The cabin air filter does the heavy lifting.

A cabin air filter is a large filter that is part of your vehicles’ cabin heating and cooling system. Almost always located behind the glovebox on the passenger side, this filter cleans the air as it is pulled into the cabin through the HVAC system, removing dust and other particulates.

The filter itself is a pleated screen usually made of paper-based, multifiber cotton. They also generally feature activated carbon, for superior filtering. However, filters are sometimes made of engineered material, and may also be scented.

So when do you need to change your filter?

Your dealer or mechanic will check your cabin air filter regularly around inspection time, and let you know if it’s time for a change. Many manufacturers will have a recommended period of time for changing your cabin air filter – it could be every 15,000 miles, or even up to every 30,000 miles.

This is all dependent on other factors as well. Maybe your vehicle is equipped with a high-end air filter, like some of the washable or scented air filters out there. This could allow you to go longer between changes. Your driving environment also matters. Urban areas, congested areas, and areas with poor air quality will all reduce the effective working lifespan of cabin air filters, as they will have to work harder.

In the end, combining all of these – manufacturers recommendations, environmental factors, and observation during service – should help you figure out when is best to replace your filter and avoid any potential issues.

Aside from a dealer or mechanic pointing it out while you’re in for service, there are a number of symptoms you can watch for.

The first will be reduced airflow – you may notice that even with your heating or AC cranked up to high, there’s not as much air flowing into the cabin. This could be because the cabin air filter is too clogged to allow the full flow through. A second symptom is musty or other unpleasant odors coming through, which can be caused by the dust and debris trapped in the filter.

Sound is also a signal that your cabin air filter needs to be checked. There are two different sounds to be alert for. The first is simply excessive noise when running your heating or cooling system – after all, you’re making the system work harder! Secondly, there may be a whistling sound from the cabin air intake ducts if your filter is backed up. This is also a sign that your filter needs to be checked.  Pay attention to these symptoms, and you’ll keep the air you breathe fresh!

Not changing your cabin air filter when recommended, or when you notice symptoms, can lead to some serious issues.

The primary concern is that a clogged cabin air filter will just recirculate poor-quality air, and won’t filter out contaminants. For drivers with allergies, this means more pollen and allergens coming into the cabin. Even if you don’t have allergies, a clogged air filter will be unable to block the pollutants that a clean one can, potentially causing breathing concerns.

Beyond just these health concerns, a dirty filter will cause your HVAC system to work harder. As it will be inefficient, the system will work harder to keep up – or you may turn it to a higher setting hoping to get more air circulating. This can damage the blower motor over an extended period of time.

Finally, the HVAC system simply won’t work as well. You may be uncomfortable in extreme heat or cold. The system may not do as well clearing fog or condensation from the vehicle’s windows, or melting off ice in the winter.

It’s up to you whether you want to have the cabin air filter replaced by a dealer or mechanic, or if you want to tackle it on your own. It’s not the hardest task, but depending on your vehicle it has different degrees of difficulty. Locating, removing, and replacing your cabin air filter on your own can be done in a few steps – check it out here or here! Cabin air filters are generally inexpensive to buy as well, with most basic air filters running under $20.