How we made this guide: picks, prices and specs come from our catalog and the makers' published specs, owner quotes come from customer reviews on our product pages and every guide is checked and edited by Trevor Hall.
HEPA stands for high efficiency particulate air. Under the US definition, a HEPA filter is tested to capture at least 99.97 percent of particles 0.3 micron in size, the definition in DOE-STD-3020, the Department of Energy's specification for HEPA filters used by its contractors. The Abatement Technologies HEPA-AIRE PAS750, at $1,139, is listed with exactly that rating: "Certified to 99.97% efficiency @ 0.3 microns."
The number matters less than what sits behind it. A rating describes the filter media. Whether the air in a room actually passes through that media depends on the gasket, the housing and how the filter was tested.
Quick answer
HEPA is a tested efficiency, not a brand or a material. In the US it means 99.97 percent at 0.3 micron. In Europe, EN 1822 grades filters by class. H13 and H14 are the usual HEPA grades. When a listing says "HEPA-type" or "99.95 percent", read the exact wording and compare it with the table below. Browse every HEPA air scrubber we carry.
What the US HEPA definition says
The common US figure is 99.97 percent at 0.3 micron. The DOE standard defines the test with an aerosol of that particle size. Industry filters are usually made to the IEST-RP-CC001 recommended practice. Abatement Technologies' PRED750 manual, for example, says its HEPA filters are made to meet IEST-RP-CC001 (Type A) and UL 900.
Why 0.3 micron? Published filter-testing guides describe it as close to the size a fibrous filter catches least well. The size between big particles that stick to fibers and tiny ones that drift into them is the hardest to stop. Particles well above or well below 0.3 micron are caught at a higher rate, but the exact weakest size varies with the filter media and the airflow, which is why the European test below finds it for each filter instead of using one fixed size.
A rating is a statement about a filter under test conditions. It is not a promise about a room, and it says nothing about illness. Below, each machine's figure is quoted exactly as our product listing states it.
H13 vs H14: the European classes
EN 1822 grades filters differently. Instead of a fixed 0.3 micron test, it finds the most penetrating particle size (MPPS) for that filter and rates it there. Published summaries of the standard give these minimum efficiencies at the MPPS:
| Class | Group | Minimum efficiency at MPPS |
|---|---|---|
| H13 | HEPA | 99.95% |
| H14 | HEPA | 99.995% |
| U15 | ULPA | 99.9995% |
Treat this as a different test, not a stricter version of the same one. A figure at 0.3 micron and a figure at the MPPS are measured at different particle sizes, so "99.97 percent" and "H13" cannot be lined up as equals. If a bid or a job spec names a class, check the standard itself.
The one machine here with a stated European class is the PrestiVac EX1-10 HEPA, at $9,995. Its listing gives 99.995 percent at 0.3 µm and names the class as H14 under the EN 1822 MPPS method. That mixes two different tests, and the class is the one a European spec will ask for. The machine is an explosion-proof vacuum built for dry material in hazardous locations, so treat it as an example of the grade, not a general pick for restoration work.
HEPA vs ULPA
ULPA means ultra low penetration air. In the EN 1822 scheme it starts at U15, listed above at 99.9995 percent at the MPPS. It sits one step above H14. None of the machines in this article is listed with a ULPA rating, and abatement specs normally name HEPA.
"True HEPA" vs "HEPA-type"
"True HEPA" is not a class in EN 1822, and it is not a separate DOE grade. It is wording that makers and sellers use to say a filter meets the 99.97 percent figure, as opposed to a "HEPA-type" or "HEPA-style" filter that does not. Look for a percentage, a particle size and ideally a class or test certificate.
The AlorAir CleanShield HEPA 550, at $497, shows why you read the sentence. Our product listing gives its HEPA efficiency as "up to 99.95% of particles 0.3 µm and larger." That is a clear, stated figure, but it is not the 99.97 percent US figure, so we do not describe it as one. If a job spec names HEPA, get the maker's filter rating in writing before you use it there.
Why the machine matters as much as the filter
A filter rated at 99.97 percent does nothing for air that goes around it. The EPA's lead renovation (RRP) rule puts it plainly for vacuums: a HEPA vacuum must have a filter that captures 99.97 percent of 0.3 micron particles, and all the air drawn into the machine must leave through that filter with none leaking past it. Three things decide whether the rating carries into the room.
- The gasket and filter frame. If the seal between the filter and the housing leaks, air takes the easy path past the media. A good frame and a tight, intact gasket keep the air on the filter.
- The housing and the clamps. A cracked cabinet, a loose access door or a slack retaining bracket is a bypass path. Abatement Technologies' PRED750 manual says to inspect and tighten the HEPA filter retaining bolts, which can loosen in transport, before running the unit. Novatek's Novair 2000 manual says to install the HEPA filter and pre-filters with a positive seal and anchor the filter with the supplied retaining brackets.
- The test. A factory rating or a DOP certificate covers the filter as it left the factory. It does not prove the assembled machine has no leak path after transport and filter changes. Where a job asks for that proof, it means a leak test of the running unit with a test aerosol and a photometer. The Novair 2000 has a variant with a metal frame HEPA filter supplied with a DOP certificate. DOP is one of the test aerosols used for this kind of filter testing.
Pre-filters protect the HEPA stage from loading up early. The PAS750 lists a coarse filter and a pleated filter ahead of its HEPA filter, and the CleanShield HEPA 550 a MERV-10 pre-filter. MERV ratings grade general HVAC filters under a different test, and no MERV number is a HEPA rating. A MERV-10 pre-filter is there to protect the HEPA stage, not to replace it.
How our machines state their ratings
Every row below quotes the filter rating exactly as our product listing states it. Airflow is "rated at" the listed or manual figure and is not a room-size claim.
| Machine | Price | Stated filter rating | Airflow or suction rated at |
|---|---|---|---|
| Abatement Technologies HEPA-AIRE PAS750 | $1,139 | Certified to 99.97% efficiency @ 0.3 microns | Up to 750 CFM |
| Abatement Technologies PREDATOR PRED750 | $1,070 | 99.97% at 0.3 microns | 200 to 750 CFM |
| Novatek Novair 2000, HEPA | $1,325 | 99.97% at 0.3 microns | 1,200 CFM low, 2,100 CFM high (Novatek manual) |
| Novatek Novair 2000, metal HEPA with DOP certificate | $1,995 | Metal frame HEPA filter supplied with a DOP certificate | 1,200 CFM low, 2,100 CFM high (Novatek manual) |
| AlorAir CleanShield HEPA 550 | $497 | Up to 99.95% of particles 0.3 µm and larger | 270 to 550 CFM |
| Abatement Technologies AIRE GUARDIAN AG3000MCCK | $4,300 | Pharmaceutical-grade HC1836-H14 HEPA filter | 300 to 900 CFM |
| PrestiVac EX1-10 HEPA vacuum | $9,995 | 99.995% at 0.3 µm, H14 by the MPPS method per EN 1822 | 135 in. H₂O water lift |
Machines that fit each rating
These are the examples worth knowing, with one line on who each suits. None has owner reviews on our product page yet, so we add no opinions.
US-rated HEPA
Abatement Technologies HEPA-AIRE Series Portable Air Scrubber PAS750
$1,139
A 33.5 lb portable listed at 99.97% at 0.3 microns, drawing 1.9 amps or less.
The PAS750 and the PRED750 are among our best-selling air scrubbers. Both come from Abatement Technologies and both state the 99.97 percent figure.
Negative air you can carry
Abatement Technologies PREDATOR Series Portable Air Scrubber PRED750
$1,070
A 35 lb scrubber listed at 99.97% at 0.3 microns, with the maker's servicing video below.
HEPA with a DOP certificate
Novatek Novair 2000 Air Scrubber and Negative Air Machine
$1,995
The metal frame HEPA variant ships with a DOP certificate, for jobs that ask for paperwork on the filter.
Lower-priced HEPA stage
AlorAir CleanShield HEPA 550 Air Scrubber with 3-Stage Filtration
$497
Stated at up to 99.95% of particles 0.3 µm and larger, so spec it only where that wording is acceptable.
HEPA stage in a containment cube
Abatement Technologies AIRE GUARDIAN Series Mobile Containment Cube AG3000MCCK
$4,300
A rolling cube whose listing names a pharmaceutical-grade HC1836-H14 HEPA filter but gives no EN 1822 test figure, so check the filter's label if a job names a class.
If the job is containment rather than scrubbing, browse mobile containment. For ducting a room to negative pressure, see negative air machines. For dust at the source, a HEPA vacuum filters the air it exhausts. Our guide on HEPA vacuum benefits covers that side.
The same machines come up in our guides to lead abatement vs lead-safe paint removal and basement mold remediation.
Getting the most from a HEPA machine
- Check the label on the actual filter, not just the listing. Filters get swapped, and a general purpose filter fits some of these machines. The Novair 2000, for example, is sold with either a HEPA filter or a 5 micron general purpose one.
- Keep the pre-filters fresh. They carry the dust load so the HEPA stage does not.
- Handle the filter by its frame, and seat the gasket flat when you close the door.
- Follow the maker's manual for filter changes. The CleanShield HEPA 550 has a HEPA change light on its control panel.
- Duct exhaust out of the work area when the job needs negative pressure, and watch the pressure difference with a manometer or a monitor such as the Abatement Technologies PPM3-S.
Frequently asked questions
Are HEPA filters necessary?
It depends on the job. Abatement and remediation specifications usually name HEPA filtration, so for that work the answer is yes. For lead renovation work, the EPA's RRP rule requires cleanup with a HEPA vacuum. For general dust a lower-rated filter may be enough. Check the job spec or the standard the client names.
Can I clean a HEPA filter?
Usually no. Abatement Technologies' PRED750 manual says its filters are not reusable and not to clean and reuse them, and Novatek's Novair 2000 manual treats its HEPA filter as a replacement part. What you can do is change the pre-filters often, so the HEPA stage loads more slowly. Never wash or blow out a filter the manual says to replace.
How long does a HEPA filter last?
It depends on the dust load, so makers go by a gauge or a light, not a calendar. Novatek's Novair 2000 manual says the differential pressure gauge reads 1.0 to 2.5 inches of water column with new filters, and that 3.0 to 3.4 inches means the filters are loaded and need changing. The PRED750 has a filter change indicator, and the CleanShield HEPA 550 has a HEPA change light.
Would an air purifier help my COPD?
We cannot answer medical questions, and a filter does not treat illness. A HEPA rating only measures how many test particles a filter catches. Ask your doctor what is right for you.
Does a HEPA filter work on COVID?
We make no health or protection claims about any machine. The rating describes particle capture in a test at a stated size. For questions about illness, ask your doctor or check the guidance published by the EPA.
What size particles do HEPA filters catch?
The US test uses 0.3 micron particles and requires 99.97 percent capture. Particles well above or well below that size are caught at a higher rate. EN 1822 rates filters at their most penetrating size, which varies by filter.
What is the ISO standard for HEPA filters?
The EN 1822 classes in this article are the European standard. ISO 29463 is the international standard that grades filters in the same style, rating them at their most penetrating particle size, so its classes line up with EN 1822 rather than with the US 0.3 micron figure. For a job spec, read the standard the client names and match the filter's stated class to it.
Put a properly rated HEPA machine on the job
