1.3 vs 1.5 vs 2.0 ATA: Hyperbaric Pressure Ratings Explained
Researched and scored by Alex Evans. Last reviewed August 2026. Corrections are dated and public. See corrections
ATA, in plain terms
You live at 1.0 ATA: one atmosphere of pressure, the weight of the air above you. A chamber adds to that. At 1.3 ATA you are carrying 30% more pressure than sea level, about what a diver feels at 3 meters. At 1.5 ATA it is half again more. At 2.0 ATA you are at the pressure of a 10-meter dive, and you have left the wellness market entirely.
Spec sheets sometimes talk in kPa instead, which measures the added pressure: 30 kPa above ambient is about 1.3 ATA, and 50 kPa is about 1.5 ATA. When a manufacturer says a shell is tested to 150 kPa and limited to 50, as the chambers in our scorecard are, that gap between tested and operating pressure is the safety margin, and it is one of the numbers we score.
The three pressure tiers
| Tier | Pressure | What lives here |
|---|---|---|
| Mild | 1.3 ATA | Soft shells. FDA-cleared for altitude sickness. The entry point. |
| Wellness hard-shell | 1.5 ATA | Home capsules and studio chambers. Where the market we score mostly lives. |
| Clinical | 2.0 to 3.0 ATA | Medical HBOT for cleared indications, physician-supervised, facility-based. |
Why pressure sets the price
Force is pressure times area, and a chamber has a lot of area. Every step up in operating pressure multiplies the load the shell, seals, doors, and windows must carry for thousands of sessions without complaint. Fabric gets you to 1.3 ATA cheaply. A tested aluminum cylinder gets you to 1.5 ATA for tens of thousands of dollars. Clinical pressure gets you into medical-device engineering and medical-device prices. When a chamber seems suspiciously cheap for its claimed pressure, the pressure claim is usually the thing that is wrong, which is why we check it first.
What this means for your purchase
Decide the pressure tier before you shop, because it decides everything else: price band, product type, and what you can honestly expect from the purchase. Then verify the chamber actually delivers its claimed pressure, in writing. The scorecard does that verification for every brand we cover, and hard shell vs soft shell covers the construction side of the same story.
Frequently asked
What does ATA stand for?
Atmospheres absolute: total pressure including the atmosphere already around you. Sea level is 1.0 ATA, so a chamber at 1.5 ATA adds half an atmosphere on top of normal air pressure.
What pressure do home hyperbaric chambers reach?
Soft shells operate around 1.3 ATA. Hard-shell home and studio chambers typically run up to about 1.5 ATA; the OxyHelp line, for example, operates at up to 50 kPa above ambient, which is roughly 1.5 ATA. Clinical chambers for medical treatment run 2.0 to 3.0 ATA.
Is higher pressure always better?
No. Higher pressure means clinical territory with clinical supervision requirements and clinical prices. The right question is what pressure your intended use actually calls for, and whether the chamber you are buying genuinely reaches it.
Five questions, and we'll match chamber, options, and install to your space and budget.