Air filters come in all shapes and sizes. They are made to clean the air of the impurities that are in it. Some are more effective than others, whilst some are better when used for a specific purpose. Merv and Hepa filter mechanics both depend on the size of particle airflow and velocity. 

The difference in the filters that you use in your air purifier of the HVAC system can be the line between clean air, and an allergic reaction to air pollutants, or an asthma attack triggered by dust or air pollutants. In this article, we take a look at the different ways in which Merv and Hepa filters are alike, and also how they differ. Let’s dive in, shall we?


Merv stands for minimum efficiency reporting value. Filters all come with a Merv rating

that is between 0 and 20. The higher the Merv rating on a filter, the more efficient it is at cleaning the air of the smaller particles such as dust, pollen, and smoke. One of the important things to note about Merv ratings on filters is that they are not standardized across all brands. You will need to do your due diligence to find out what the Merv rating on your particular brand means. 

Merv is a rating used on filters and helps you know to what extent it can clean the air for you. Merv ratings are between 1 and 20. 1 is the lowest efficiency and 16 is the highest efficiency possible. Filters with a Merv rating between 1 and 4, won’t clean the air much. 

Between 5 and 8,  means that you have a medium rated filter, trapping particles as small as 3 microns in size. If the filter has a Merv rating of between 9 and 12, it is pretty close to a Hepa filter and can trap small airborne particles. 

A filter with a Merv rating of between 13 and 20, is extremely efficient. These will be able to trap dist, viruses, carbon particles, and bacteria. It is more likely that this is the type of filter that you will find in a medical institution. 


Hepa is an acronym for high-efficiency particulate air and this is a way of measuring the quality of the air in a room. If a filter is said to be a HEPA filter, it needs to meet certain standards for it to be said to be a HEPA filter. A Hepa filter needs to get rid of at least 99.95% of air contaminants. The particles should at least be as small as 0.3 microns in size as well. 

Hepa filters have a higher Merv rating than Merv filters. They usually range from17 to 19. The rating system on the Hepa filters is different. They are rated from E10, which is the lowest, capturing 85% of airborne particles, and they go up to H14, where 99.9%of airborne particles are trapped. This is the highest rating. 

Favourite Features


Rating: Merv is rated from 1-20. 1-4, will trap particles greater than 10microns in size. It is the lowest possible filtering on a filter.

Determined by: ASHRAE standard 52.2

Particle size: at its highest rating, a Merv filter will clean the air of particles that are 0.3microns in size


Efficiency: Hepa air filters are the only mechanical filters tested to meet a certain efficiency.

Rating: Hepa air filters should have a 99.97% rating. They are the most common home filters.they are classed from E10 to H14. The H14 rating will see you capturing up to 99.9% of the airborne particles. 

Feature 1

Merv  of filters are rated according to ASHRAE standard 52.2. The Merv rating will depend on what you want to filter. Hepa filters are rated according to the Environmental Sciences and Technology (IEST)-RP standard, in the US, and by the EN 1822:2009 in the EU. 

Feature 2

Hepa filters are made of a mat of entwined fiberglass. The fibers are randomly layered in such a way that they trap the smallest of particles. Merv filters are also made of fiberglass, but they can also be made of different materials to increase the amount of resistance in an air purifying unit.

Feature 3

The size of the filter that you get, depends on the specifications of your air purification system. You want to get something that fits the unit properly. 

What could be better


Merv filters do not filter the air as effectively as HEPA filters. Even the highest Merv rating, is still not entirely as good as Hepa filters.


They need an extra fan to filter the air, meaning that your HVAC system has to be compatible. If it’s not compatible with the filter, it can drive up your energy cost. Also, replacement filters can be costly. They do not filter gas particles

Similar Features

Both Merv and Hepa, are measurements of how clean the air is. they are a great way to know such important information. Merv and Hepa filters, both capture some of the finest particles in the air.  Also, both Merv and HEPA filters are made of fiberglass, however the material in Merv filters can differ.

Key Differences 

One of the key differences between Merv and Hepa filters is that Merv is rated between 1 and 20. And yet even at the highest Merv rating, Hepa filters still filter smaller particles.  

Whilst heap filters will have a Merv rating, they do not undergo Merv testing, and this is where the confusion usually comes into play.

Leave a Reply

Your email address will not be published. Required fields are marked *