30 Aug, 2021

Don’t you just love the feeling of stepping into your car’s air-conditioned cabin on a hot summer day? Your car’s climate control system might seem like a simple creature comfort, meant to shield you from the heat or cold of the outside world, and in an earlier era of automobiles, it was just that. Today, however, automotive HVAC (Heating, Ventilation and Air Conditioning) systems are more advanced—they play a critical role in safeguarding your health from contaminants both inside and outside your vehicle’s cabin. 

Dirty Air, Everywhere

Much of the air we breathe, especially in cities, is contaminated with all sorts of pollutants—dust, pollen, harmful gases, and pathogen. These pollutants exist in your car’s cabin too, making their way in every time you open the door or roll the window down. The HVAC system too sucks these pollutants in with the outside air. All in all, the problem of dirty air is pervasive, and it is something modern automotive HVAC systems have to contend with.

Cabin Air Filters

To combat the problem of contaminated in-cabin air, modern HVAC systems are fitted with air filters that trap particulate matter before the cooled or warmed air is blown into the cabin. The idea of using an air filter isn’t new, but better manufacturing and material technologies have vastly improved the efficacy of such filters. 

Bigger, Better Air Filters

Modern HVAC systems now employ bigger air filters that can trap contaminants over a larger surface area, while also allowing for better airflow into the cabin. Air filters are usually made of porous materials that can trap particles several times thinner than a human hair. Since particulate matter poses some of the greatest health hazards to humans, air filters are a tremendous way to improve the air quality of a car’s cabin. The cabin air filters employed by the MG Gloster and ZS EV can trap particles as small as 2.5 microns wide, about 30 times smaller in diameter than a human hair. Click here to know more about how your ZS EV helps you breathe better. 

The material an air filter is made from also impacts its efficacy. Older air filters were made using tightly woven fabrics or paper-based multi-fibre cotton. Modern air filters employ non-woven materials that are made by combining strands of a material using chemical or thermal processes as opposed to weaving. Non-woven fabrics offer fantastic filtration performance because they can be manufactured to exact specifications and with very specific properties. Frequently, filters made with non-woven materials also enjoy longer lives, thus reducing the cost and waste associated with replacing them. 

Higher-end cabin filtration systems may also utilise activated carbon as the filtration medium. Activated carbon, also known as activated charcoal, is an engineered form of carbon that is highly porous. As such, it provides a large surface area of carbon for air to make contact with. Carbon is an effective cleaning agent, and an activated carbon filter can not only trap particulate matter but harmful gases, odours, and pathogens too.

For maximum efficiency, automotive HVAC systems may employ multi-stage filters. A multi-stage filter uses several different filtration mediums, each specifically designed to filter a particular type of pollutant.

Optimising Filter Performance

The air filters used by automotive HVAC systems are static devices. Over time and use, they will get clogged up. This will reduce the efficiency of not only the filter, but of the HVAC system as a whole. A clogged filter will block airflow to the vents, pass on odours into the cabin, and host unwanted microbial growth on the filter surface. 

To optimise filter performance, refer to your vehicle’s manual for the ideal filter replacement interval. This interval is a useful guideline, but if you drive in heavily urban or otherwise dusty, polluted environments, you might have to replace your filter sooner. 

A clogged filter can be identified by reduced airflow from the HVAC vents, undesirable odours being blown into the cabin, or whistling sounds from the ducts. It is advisable to change the cabin air filter as soon as possible after one or more of these symptoms have been identified. A clean filter will do wonders for the efficiency of your HVAC system as well as your health.

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