HEPA Filter H13 Vs H14: What Is The Key Difference Here?

As we know, H13 and H14 are two classifications of HEPA filters. The difference between H13 and H14 HEPA filters is simple; H14 HEPA filters are better due to higher efficiency and lower penetration rate. When differentiating between H13 vs H14, it is crucial that we also understand the implications of using H14 over H13 HEPA filters in air filtration devices.

Namely, HEPA filter or High Efficiency Particulate Air filter is a type of pleated mechanical air filter. These filters are used in medical environments (clinics, hospitals, operating theaters), the pharmaceutical industry, nuclear facilities, and, until quite recently, in a residential air purifier. We differentiate between H10 (E10), H11 (E11), H12 (E12), H13, and H14 HEPA filters.

H13 and H14 HEPA filters are used when you need the cleanest possible air. Obviously, H14 HEPA filters remove more airborne air pollutants than H13 HEPA Filters. According to the DOE’s Technical Standard definition:

“(HEPA) filter shall exhibit a minimum efficiency of 99.97% when tested with an aerosol of 0.3-micrometer diameter.”

This is a standard for True HEPA filters, classified as H13 HEPA filters. In short, the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) measures how well do filters capture 0.3 micron-sized air particles. These are the most penetrating particle sizes (MPPS) and a used as a point of reference for efficient particulate air filters.

Now, let’s see how H14 HEPA filters are better than H13 HEPA filters at trapping airborne particles. Even more importantly, we are going to look at an example of what using H14 vs H13 entails (in terms of airflow, fan motor power, and noise levels):

H13 VS H14 HEPA Filter Standards And Implications

Here are the performance standards for H13 and H14 HEPA filters:

• H13 HEPA filter is capable of capturing 99.97% of 0.3-micrometer air particles. That means that the penetration rate is 0.03%; 30 air particles out of 1,000,000 will penetrate an H13 HEPA filter.
• H14 HEPA filter is capable of capturing 99.99% of 0.3-micrometer air particles. That means that the penetration rate is 0.01%; only 10 air particles out of 1,000,000 will penetrate an H14 HEPA filter.

If we simplify H13 vs H14 HEPA filter efficiency, we can see that H14 HEPA filters are 3x better at capturing airborne particles like dust, smoke, pollen, mold, and so on.

In short, if you want the cleanest possible air, you should always opt for H14 over H13 HEPA filter.

Now, using H14 HEPA filters will require quite a lot of airflow and before-filter air pressure in order for H14 HEPA to do its job properly. That’s why, until recently, H14 HEPA filters were only used in big commercial air cleaners for hospitals, clinics, and the pharmaceutical industry.

Quite an interesting development in the last few years are H14 HEPA air purifiers. This comes from the desire of breathing the purest possible air. The thinking here is why only use H13 HEPA filters if we have H14 HEPA filters available. They are, if you compare the reduced penetration rate, 3 times better than H13 HEPA filters.

The implications of using H14 HEPA filters over H13 HEPA filters are most apparent in the new lines of residential air purifiers. Let’s look at the best example that will illustrate why only a few manufacturers are actually capable of including H14 HEPA filters in their air purifier’s filtration system:

Example For Residential Use: H14 HEPA Air Purifiers

The common goal of all air purifiers is to produce the purest air possible. Obviously, that means you have to use H14 HEPA filters instead of H13 HEPA filters. Quite until recently, no manufacturer was offering H14 HEPA filters. Why is that?

Well, the H14 HEPA filters have a much finer fibrous structure than the H13 HEPA filters. That means that the pressure drop across the H14 HEPA filter is higher than the pressure drop across the H13 HEPA filter. To simplify; you need a fan motor to generate enough pressure for air to flow through the filter in significant quantities (airflow).

Getting a powerful enough motor is usually not a problem in big medical facilities. For residential homes, however, air purifiers were developed with fan motors that are too weak to push a considerable amount of air through an H14 HEPA filter. There is also a con of using a bigger motor; energy expenditure is that all that bigger but the noise output can be higher on account of fan motor creating more air pressure.

The only manufacturer that currently offers residential H14 HEPA air purifiers is Medify Air (only 1 model is powerful enough for a H14 HEPA filter). They were also one of the first brands to offer H13 air purifiers and are basically spearheading the whole residential air cleaning industry.

The key part that Medify Air purifiers require is a powerful enough fan motor. Here you have to be aware that not all Medify Air units have the capacity to carry H14 filters. Namely, smaller units like MA-14, MA-15, MA-25, and even M-50 cannot operate with H14 HEPA filters.

The only currently available H14 HEPA air purifier on the market is the big Medify MA-112. That is only possible because it has a record-breaking 559 CFM airflow (950 m³/h) for a home air purifier.

This is sufficient airflow to create enough pressure across an H14 HEPA filter to facilitate a significant airflow. That outcoming airflow, however, is as purest as they get and increases the indoor air quality (IAQ) the most of all air purifiers on the market.

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All in all, we can see that there is a 0.02% penetration rate difference between H14 and H13 HEPA filters. H14 HEPA filters have higher performance than H13 HEPA filters but they cannot be used in devices with weak(er) fan motors.