Air filters for bus HVAC’s improve air quality for passengers and reduce maintenance costs

June 23, 2020

In today’s environment, transportation agencies are increasingly focused on reducing the risk posed by pollutants and airborne contaminants to deliver the safest environments for their customers. Thermo King’s return air filters provide the maximum protection for both riders and the HVAC equipment. Our filters prevent particulate accumulation on evaporator coils resulting in reduced road calls from HVAC system failures.

Thermo King offers three air filters in several filtering efficiencies with different contaminant holding capacities.

What MERV rating means in air filtration

A clear strategy to mitigate in-cabin contaminant exposure to passengers and reduce HVAC maintenance costs is to use a quality filter with a high Minimum Efficiency Reporting Value (MERV) and efficiency rating.

A filter with a higher rating is more effective at filtering out contaminants and small particles.

Merv Rating Levels

Between 1-4

  • Captures: less than 20% of particles between 3-10 microns in size
  • Including: dust mites and pollen

Between 5-8

  • Captures: 20% - 70% of particles between 3-10 microns in size less than 20% of particles between 1-3 microns in size
  • Including: mold spores and cement dust

All three air filters meet the standard set forth by the Federal Motor Vehicle Safety Standard 302 (49 CFR 571.302) and American Society of Heating, Refrigerating and Air-Conditioning Engineers Standard 52.2-2007. They are also disposable.

How an inefficient filter can affect your bottom line


Non-OEM filters can create many downstream impacts to the reliability of your Thermo King system. Over time, this could make your system work harder than it needs to and lead to early system component failure.

Other pitfalls:

  • Using filters that create airflow restrictions in the HVAC system leads to reduced cooling ability and creates the potential for evaporator coil freeze.
  • Low MERV and loose-fitting filters allow for air bypass and results in additional preventative maintenance procedures, such as coil cleaning.
  • Dirty evaporator coils reduce the cooling capacity and decrease efficiency of the system.

Bus HVAC Systems


Let us be your first line of defense against contaminated air

We understand that you are working tirelessly to provide a safer environment for your customer. Air filters are an essential part of that process. Let us help you provide cleaner, higher-quality air, and keep your HVAC system clean and operating efficiently.