Before we get down to the nitty-gritty of how often you should change your air conditioner, cabin, car or home air filter, let’s revisit the fundamentals of air filters. A particulate air filter, also known as an air cleaner, is a device made of fibrous (natural or synthetic) or porous materials that remove solid particles such as small stones, dust, pollen, mould and even bacteria from the air. Other filters that contain a catalyst or absorbent such as charcoal, remove odours and gaseous pollutants. Air filters are normally used in places where the quality of air is vital.

There are several types of filters used, but the most commonly used are:

HEPA Filters

High-efficiency particulate air filter, also known as high-efficiency particulate absorber/arresting is the most popular and well-known filters in the market. HEPA filters remove a high percentage of particles in the air as it passes through the air purifier. These filters are able to remove 99.97% of airborne particles whose size is equal to or greater than 3 micrometres in diameter. They are mostly used in medical facilities or by homeowners who suffer from severe allergies.

Pleated Air Filters

These filters are made of polyester-blend fabric or folded cotton sheets that offer a much higher level of filtration than other standard filters. This allows the entire filter to trap even microscopic airborne particles which could potentially harm the furnace blower fan or clog the AC coils. They are normally the exclusive choice for automobile engine air cleaners and also home for people with severe allergies as they are efficient, easy to service and cost-effective.

Carbon Air Filters

Carbon air filters utilize activated carbon to absorb and neutralize elements in the air such as chemicals and gaseous odours. The filters function to neutralize these elements as the air travels through the filter. Carbon is ideal for removing smoke and are highly suitable in industries.

Ultra Violet Light Filters

UV light is a light bulb that is usually inserted into the heating and cooling system and can eliminate 99.9% of microorganisms and destroy viruses in the air. Harmful particles such as bacteria and viruses are neutralized through exposure of titanium dioxide to UV light. The type and quantity of microorganisms destroyed depends on the output of the lamps, and the length of exposure. Due to their ability to effectively destroy the majority of the microorganisms, they are normally used in medical facilities alongside HEPA filters.

Ionic Air Filters

Ionic air filters release negatively charged ions as a means to attract the particles present in the air. As the two bombards, they are deionized and filtered out of the air. Also known as air ionizers, they are commonly used in commercial sectors.

Automotive Cabin Air Filter

The cabin air filter is a pleated-paper filter that is placed in a vehicle’s cabin in the outside-air intake for the vehicle’s passenger compartment. Although most are rectangular, some are designed to fit the available space in particular vehicles. This filter is a recently added accessory with models made from the year 2000 having this feature.

Fiberglass Air Filter

These are the most commonly used type of air filter, as they are extremely affordable and easily disposable. Although highly effective in protecting equipment from dust particles, they are less effective in cleaning the air around the house.

Why should you change your air filter?

Filters tend to get clogged and once their capacity has been reached or exceeded, the dirt is released back down into the system, into the heat exchanger covering the duct-work and blower motor. This dirt can cause malfunctions and other issues in the electrical and mechanical parts resulting in the high cost of repair thus making it imperative to know when to change your air filter regardless of the type.

How often should you change the air filter at home?

Changing the air filter at home depends on:

  • The type of filter being used
  • The overall quality of air indoors
  • Number of pets in a home
  • Number of persons living in a home
  • Level of air pollution around the house

For basic filters, instructions from the manufacturer state that they should be changed every 30-60 days. In case the residents suffer from allergies, it’s advisable to change them more often while in a remote area, they should be changed annually. The number of pets also increases the number of times an air filter should be changed.

To change a home air filter, the first step is to turn off the furnace. Then you will have to locate the filter on the furnace, measure the size of the filter, remove the old and worn out filter, insert a new filter and finally turn the furnace to “on” position.

How often should an engine air filter be changed?

The air that enters the engine flows through the air filter in order to protect the engine from sand and other debris helping it last longer. These filters are normally made of pleated paper which traps dirt and other objects. If they get clogged, the air movement into the engine is restricted causing particles being sucked into the engine pistons and cylinder walls.

This can result in mechanical malfunction of the engine while causing lack of power on hard acceleration. The engine air filter is changed often depending on the mileage of the vehicle normally between 15,000-30,000 miles and also the driving conditions. Driving unpaved roads with loose surfaces means that the air filter should be changed more often as opposed to vehicles that are not driven a lot.

To change this filter, you need to locate the black plastic casing on top or in front of the engine. This casing is held together by screws or metal clips. Once you loosen the clips, open the casing, remove the filter, clean the inside if the casing to remove excess debris, replace the filter then close the casing.

How often should an automotive cabin air filter be changed?

As a new feature in vehicles, most drivers don’t even know that this filter exists. It is typically located behind the glove compartment or under the hood or dashboard in the modern vehicles. This filter plays an important role in filtering pollutants from entering the vehicle’s cabin through the car’s HVAC system.

The cabin air filter should be replaced depending on the mileage, mostly between 15,000 to 25,000 miles or at least once a year. Although it’s a do-it-yourself job to change this filter, some may be hard to remove. One needs to access the filter by removing the glove box and taking off a few clips and pins, removing and replacing the filter before putting back the accessories in place.

Air filters are a crucial part of living spaces, vehicles, commercial and industrial areas. Choosing the appropriate air cleaner for your particular space is a question that most people ponder upon. MERV, Minimum Efficiency Reporting Value, should help answer the question: how effective is an air filter? The higher the MERV, the more efficient the air cleaner and vice versa. Also, you should make sure that you maintain the manufacturer’s instructions in order to reap maximum benefits from the air filter you’ve chosen.