Buying an air purifier often starts with a simple question: which filter should I look for? The answer gets less straightforward once you start reading the specifications. H13 and H14 appear on some models, while others simply say “True HEPA”. Then there are filtration claims such as 99.97% or 99.99%, often displayed prominently on product pages and packaging.
At a glance, all of these labels can make an air purifier sound highly capable. But they don’t necessarily describe the same thing, and comparing them by the numbers alone can give you the wrong impression. There’s also some confusion around whether H13 and H14 are Indian standards, what “True HEPA” actually signifies, and whether paying more for a higher-rated filter will make a noticeable difference in a room.
Here’s what these labels actually mean, how they are tested, and what you should look for beyond the HEPA badge when comparing an air purifier.
The easiest way to understand H13 and H14 is to look at the standard behind the number instead of the percentage printed on the front of the box.
Under EN 1822, HEPA filters are classified according to how well they capture particles at the filter’s most penetrating particle size (MPPS). This is the particle size at which a filter is least efficient, which makes it a useful point for testing.
An H13 filter has a minimum efficiency of 99.95% at MPPS, while H14 is rated at 99.995%. The difference between the two percentages looks tiny, but the amount of particles allowed to pass through is ten times lower for H14 under the specified test conditions
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| HEPA class | Minimum efficiency at MPPS | Maximum penetration |
| H13 | 99.95% | 0.05% |
| H14 | 99.995% | 0.005% |
One thing worth keeping in mind is that these numbers describe the filter under a defined test. They don’t tell you how quickly an air purifier will clean a particular room.
An H14 filter inside a purifier with weak airflow won’t necessarily outperform an H13 filter in a machine that can move much more air.
“True HEPA” is one of those terms you’ll see repeatedly when looking at consumer air purifiers. It is generally used to distinguish a HEPA filter from products that use looser descriptions such as “HEPA-type” or “HEPA-like”.
But there’s no H13 or H14 classification hidden inside the words True HEPA. If that’s all a manufacturer tells you, you still don’t know the exact grade of the filter.
The useful information is usually further down the specification sheet. Look for the stated efficiency, testing standard or a specific filter classification. If a brand gives you those details, you have something concrete to compare.
The useful information is usually further down the specification sheet. Look for the stated efficiency, testing standard or a specific filter classification. If a brand gives you those details, you have something concrete to compare.
With HEPA-type, HEPA-style and HEPA-like, the wording is even less specific. They may describe filters intended for high-efficiency particle filtration, but the terms themselves don’t establish an H13 or H14 rating.
H13 and H14 are not Indian filter grades. They are classifications under the European EN 1822 standard, and the same classifications can be used for HEPA filters in air purifiers sold in India.
India has its own standards relating to air quality and air-cleaning equipment, but there isn’t a separate Indian version of H13 or H14 that brands are expected to use for consumer air purifiers.
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So if an Indian product listing says “H13 HEPA filter”, H13 is referring to the filter classification, not a BIS-created Indian grade. If a manufacturer mentions BIS certification or an Indian standard, check which standard it is referring to and what exactly was tested.
There is a straightforward answer at the filter level: H14 is more efficient than H13. Whether that difference is worth paying for depends on the purifier around the filter. Air has to be pulled through the media, and a filter that is extremely efficient but paired with limited airflow won’t magically make the machine better at cleaning a room.
This is where CADR becomes useful. If an H14 purifier has substantially lower CADR than an H13 model, I’d look carefully at both before spending more on the H14.
For most buyers, the combination of filter efficiency, airflow and CADR is more useful than the HEPA grade on its own.
Then there’s the number that appears on countless air-purifier boxes: 99.97%. You’ll commonly see it alongside “True HEPA”, particularly in products using terminology based on US filtration standards. It shouldn’t, however, be placed directly next to H13’s 99.95% figure and treated as a simple higher-versus-lower comparison.
The testing standard, particle size and conditions behind the percentage matter. A 99.97% claim and an H13 classification can come from different testing conventions.
So when one brand says 99.97%, another says H13 at 99.95%, and a third says H14 at 99.995%, don’t pick the third one just because its number is the largest. Find out what was tested and how the manufacturer arrived at the figure.
Once you know what the labels mean, the specification sheet becomes easier to read. I’d start with the filter itself: if the manufacturer gives a specific H13 or H14 classification and identifies the standard, that’s more useful than a generic “True HEPA” claim.
After that, look at CADR and the recommended room size. The purifier needs to move enough air for the space, regardless of how efficient the filter is.
The replacement filter deserves a look before you buy as well. Check how much it costs and whether it’s readily available. That’s a recurring expense you’ll have to deal with long after the original purchase.
I’d also check how the filter sits inside the purifier. If there are gaps around it, some air can bypass the filter media altogether.
H13, H14 and True HEPA are useful labels, but they only make sense when you know what sits behind the claim. For a home air purifier, the filter grade is one part of the equation; the machine’s ability to move and clean air matters just as much.
So, don’t let the biggest filtration percentage on the box make the decision for you. Read the standard, check the purifier’s airflow and CADR, and then decide whether the filter actually fits your room and usage.
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