How to Select Best Cabin Air Filter

Similar to an engine air filter that prevents debris and dust particles from entering the engine, a cabin air filter is very important for the healthy environment within the passenger compartment of a vehicle. A cabin air filter is the first and the most important component of the heating, ventilation, and air conditioning system of a vehicle. 

A good cabin air filter does not allow soot particles, exhaust gasses, bacteria and other allergens, air pollutants, or foul and unpleasant odors, and keeps an appropriate amount of air circulation from the vehicle’s cabin. 

Without a properly working cabin air filter, the air inside of a vehicle’s passenger compartment is prone and susceptible to be polluted with several harmful particles and gasses which will put the life of passengers in danger. 

Therefore, a properly working cabin air filter is extremely important for the health and safety of passengers.

How to Select Best Cabin Air Filter

Primarily, a cabin air filter is designed to filter out harmful pollutants and foul odors from entering the heating and air conditioning system of a vehicle. But several factors should be considered before choosing a cabin air filter for a vehicle. These factors have been discussed below one by one.

1. Types of Air Filters available

There are the following types of cabin air filters available in the market. Each of them has a few pros and cons over the other. A better choice can be made according to the specific requirements and conditions. 

1.1 Charcoal or Activated Carbon Air Filter

This type of filter is also known as an activated charcoal air filter. An activated carbon filter has a bed of activated carbon in granular form and has millions of tiny pores. 

The filter prevents the entry of foul and unpleasant odors through the process of absorption. In this process, the molecules of incoming dirty air stick with the surface of charcoal molecules, and pure air enters the system. 

The major advantage of this type of filter is its ability to capture volatile organic compounds (VOCs). Whereas one of the main disadvantages of this type of filter is its inability to filter dust and other particles.

1.2 Baking Soda Air Filter

Another type of air filter that is known as baking soda air filter uses the ability of baking soda to neutralize foul and unpleasant odors. The baking soda reacts with the molecules of incoming odors and dirty air and neutralizes them chemically.

1.3 HEPA (High-Efficiency Particulate Air) Cabin filters 

HEPA air filters are a very common and famous type of air filter available in the market. These are a kind of pleated mechanical filter that can capture dust and other particles from entering the HVAC system of a vehicle. The prime disadvantage of HEPA filters is their inability to capture foul and unpleasant odors.

2. Filter Efficiency rating

There are different types of standards and ratings used to evaluate the performance and capability of the air filter to block different particles and foul odors.

2.1 MERV (Minimum Efficiency Reporting Values) Rating

MERV rating is the most common rating standard amongst all the other standards and has been recognized and acknowledged by different filter manufacturers. 

It has been developed based on some experimental tests devised by the ASHRAE (American Society of Heating, Refrigerating, and Air Conditioning Engineers). The MERV rating ranks a filter on a level from 1 to 16 based on its ability to restrict a particle of a specific size to pass through it. 

A filter with a rating above 8 is considered to be a good filter whereas the filter with a rating near 15 or 16 is remarked as the best filter amongst those being compared. 

2.2 MPR (Microparticle Performance Rating)

MPR rating has been developed by 3M company to rate the filter's ability to trap different air particles of size less than 1 micron. A filter with a rating above 600 MPR is considered good for normal dust and pollen particle trapping.  

2.3 FPR (Filter Performance Rating)

This standard has been developed and devised by Home Depot Company to rank the filters based on their ability to prevent different pollutants from passing through them. The rating standard starts from 4 and ends at 10. A filter with a rating between 4 and 5 is considered to be a good filter.

2.4 Beta Ratios

Another standard for rating the performance of an air filter is the beta rating. Beta rating is different from other rating standards in a way that it is an absolute standard rather than a relative one. This rating is based on the Multipass Method for assessing the performance of a filter element. 

In this standard of rating, the amount of particles of a specific size (in microns) upstream of the filter and the number of particles downstream of the filter is obtained, and based on these values, the beta ratio of a filter is calculated. 

A filter with a beta ratio of 20 is considered to be good whereas a filter with a beta rating of 1000 is considered the best among all the filters being analyzed.

3. Filter Durability

The durability of a filter is an important characteristic and must be assessed before choosing a cabin air filter from the available options. A filter can be made of carbon, aluminum, fiberglass, foam, paper, and plastic. 

It is very obvious to note that the filter made up of aluminum and other metals such as steel are amongst the most durable. Furthermore, a filter made up of pleated or folded material is more durable and has a significantly longer working life.

4. Replacement Interval

The replacement of a cabin air filter is usually associated with the mileage of the vehicle. The replacement interval may stretch or contract based on the outside environment, type, and quality of the cabin air filter. 

A cabin air filter normally needs to be changed every 15,000 to 30,000 miles. However, the replacement interval may vary with the intensity of its usage. HEPA (High-Efficiency Particulate Air) filters have comparatively longer replacement intervals than activated carbon intervals.

5. Price

There is a wide variety of cabin air filters that are available in the market. The price of a cabin air filter changes with the change in the car’s model and manufacturer. 

Both HEPA (High-Efficiency Particulate Air) and activated carbon air filters are easily available in the market. Activated carbon air filters are cheaper than HEPA filters but the HEPA filters are more efficient in controlling the dust particles entering the heating and air conditioning system of a vehicle.

6. Filter Design and Material

Cabin air filters or generally speaking air filters are made from a wide range of materials. Cabin air filters are usually made from fiberglass (non-pleated) or fiber-based cotton and paper-based materials. Older cabin air filters were round and had both pleated and un-pleated construction. 

But nowadays, cabin air filters are straight and in most cases have pleated or folded structures to increase their surface area to capture pollutants. Furthermore, a cabin air filter has layers of material one behind the other to capture the pollutants layer by layer. 

They are made in such a way that the largest particles are trapped on the outside layer and the smallest particles are filtered out in the interior layer. Therefore, it is a wise decision to buy a pleated and strongly meshed cabin air filter to obtain optimal performance and results.

7. Airflow restriction

A cabin air filter has a porous surface or surfaces that allow air to pass through them easily and restrict the entry of pollutants and other unwanted particles. 

A new or properly cleaned cabin air filter performs its job quite efficiently but with the usage, a cabin air filter will be full of dust and other particles entrapped in its pores. 

Therefore an old cabin air filter may restrict the airflow and hence can deteriorate the performance of the entire heating and air conditioning system. 

Furthermore, a highly rated cabin air filter on any standard such as MERV, MPR, FPR, or Beta might restrict the airflow as well because the size of filter pores decreases with the increase in its rating. 

8. Noise Generation

Noise generation is not a very common phenomenon that you would encounter while dealing with cabin air filters. A suitable cabin air filter according to the model and the make of the car will not produce any noticeable or audible noise. 

If an activated carbon cabin air filter is making noise, you might need to replace it as they are not reusable usually. On the other hand, HEPA filters can be cleaned to reduce noise.

The problem of noise generation in a cabin air filter might raise due to the following factors

If the cabin air filter is not clean, then it won’t allow air to pass through it easily and you may hear a detestable or whistling sound from the filter.

An old or improperly fitted cabin air filter can also generate blowing noise when the air passes through or beside it. Hence, keeping in view the aforementioned points, the selection of the best cabin air filter may vary from situation to situation.