1.3 vs 1.5 ATA Hyperbaric Chambers: What the Number Means

Buyer's guide · Hyperbaric chambers

By Andrew Garcia, co-founder of The Recovery Outlet. Prices checked against our catalog on September 8, 2026.

Every home hyperbaric chamber is sold by one number: 1.3 ATA, 1.4 ATA, 1.5 ATA, 2.0 ATA. The number decides the price, the shell, the oxygen equipment you need, and whether what you are buying is closer to a wellness tool or a clinical one. This guide explains what the number means in plain terms, what changes between 1.3 and 1.5, and which chambers we carry at each pressure.

What ATA means

ATA stands for atmospheres absolute. The air pressure at sea level is 1.0 ATA, about 14.7 pounds per square inch. A chamber rated 1.3 ATA adds 30 percent to that, about 4.4 psi above the room. A 1.5 ATA chamber adds 50 percent, about 7 psi above the room. In diving terms, 1.3 ATA is the pressure about 10 feet under water, 1.5 ATA is about 16 feet, and 2.0 ATA, where most hospital chambers operate, is 33 feet.

Pressure matters because of a physical law. The amount of a gas that dissolves into a liquid rises with the pressure of that gas above it. Under pressure, breathing oxygen from a concentrator, more oxygen dissolves directly into the plasma of your blood rather than riding only on red blood cells. That dissolved oxygen is the whole point of the chamber, and the higher the pressure and the purer the oxygen, the more of it there is.

What changes between 1.3 and 1.5 ATA

Three practical differences follow from the table.

• The shell has to hold more. At 1.3 ATA a fabric chamber with a zipper is enough. At 1.5 ATA the fabric is heavier, the seams are welded in more layers, an internal steel frame holds the shape, and the best units use a rigid stainless vessel with a polycarbonate window. That is most of the price gap.
• The compressor works harder. More pressure means a larger air compressor running longer, which means more electricity and more noise. Ask for the decibel figure.
• The research lines up with 1.5. Most of the published trials on mild hyperbaric oxygen for cognition, post-concussion symptoms and healthy aging used 1.5 ATA or higher with oxygen delivered by mask. There is less published work at 1.3 ATA, and what exists is smaller. That is not a claim that 1.3 does nothing. It is a statement about where the evidence sits.

Mild hyperbaric at home is not clinical HBOT

This is the part most product pages skip, and the reviews on other sites show that buyers find out later. Clinical hyperbaric oxygen therapy, as the Undersea and Hyperbaric Medical Society defines it, is breathing near 100 percent oxygen at 1.4 ATA or higher in a chamber, prescribed by a physician for a list of approved conditions such as decompression sickness, carbon monoxide poisoning and certain non-healing wounds. Those treatments run at 2.0 to 3.0 ATA in a hard chamber with a medical team present.

The soft chambers sold for home use are cleared by the FDA at 1.3 ATA for one indication, acute mountain sickness. Everything else people use them for, recovery after training, sleep, general wellness, is off-label and unproven in the regulatory sense. The FDA published a consumer update saying exactly that, and we link it below. We sell these chambers as recovery infrastructure, the same way we sell a sauna or a cold plunge, and anyone managing a medical condition should talk to their physician before buying one, not after.

Two safety points that follow from this. The chamber is pressurized with room air, and oxygen comes to you through a mask or cannula from a concentrator, so the atmosphere inside a soft chamber stays close to normal air and the fire risk is managed by design. Hard shell units with a built-in concentrator can hold a higher oxygen fraction inside, which is why they ship with strict rules on what you bring in. Follow them. And the pressure change itself is felt in the ears the way it is on an airplane. Anyone with a cold, sinus congestion, an ear condition, or an untreated lung condition should not use a chamber until cleared.

The concentrator question

The single most useful question to ask any chamber seller is whether the oxygen concentrator is included, and what it is. A chamber without a concentrator is a pressurized room of ordinary air. At 1.3 ATA breathing air, the oxygen you get is about 30 percent more than at sea level. At 1.3 ATA breathing 95 percent oxygen through a mask, it is several times more. The concentrator is where the benefit lives.

The Oxygen Health Systems chambers we carry at 1.4 and 1.5 ATA ship with a DeVilbiss 10 liter per minute concentrator that is FDA approved as a medical device and delivers 95 to 96 percent oxygen. The 1.5 ATA hard shells build the concentrator, the compressor and a dehumidifier into one cabinet. On the Newtowne 1.3 ATA chambers, confirm the concentrator with us at the time of order, because the configuration changes and we would rather quote you the current build than a page.

What we carry at each pressure, with prices

The whole catalog is on the hyperbaric chambers collection. For the soft shell versus hard shell decision on its own, read our practical buyer's guide.

Power, noise, space and delivery

• Power. Every chamber above runs on a standard 110 to 120 volt outlet. The complete 1.5 ATA soft shell system draws about 1,460 watts and the 30 inch hard shell about 1,200 watts, which is 10 to 12 amps. Give it a dedicated 15 amp circuit and do not share it with a space heater or a sauna.
• Noise. The compressor is the noise. Figures we have seen on units in this class run from the low 50s to the high 60s in decibels, which is a quiet conversation up to a dishwasher. Ask us for the figure on the exact model, and place the compressor on a mat in the next room where the hose length allows.
• Space. A 32 inch lie-down chamber is 89 inches long. Add three feet at the entry end for the zipper and two feet on the compressor side. A sitting chamber trades floor length for height, and the walk-in vertical models suit anyone who cannot climb into a tube. Soft shells deflate and store. Hard shells do not.
• Sessions. Home protocols in the published research run 60 to 90 minutes, several times a week, in blocks of 20 to 60 sessions. Plan for the chamber to be used at the same hour most days, because the results in the studies came from consistency.
• Delivery. Hyperbaric chambers ship freight in 2 to 4 weeks, curbside unless inside delivery is added. Report any damage within 48 hours with photos. In-home setup is available on select equipment and scheduled separately. Chambers are HSA and FSA eligible for many buyers with a Letter of Medical Necessity, and Affirm financing is available at checkout. Our shipping policy has the detail.

Which pressure to buy

• 1.3 ATA when the budget is under $10,000, you want an American-made chamber, and the use is general recovery and sleep. Confirm the concentrator. Without one, you are buying pressure and not oxygen.
• 1.4 ATA when you want the included FDA approved concentrator, the 3 year warranty and the steel frame, and you want a sitting or walk-in design. This is the sweet spot of the catalog for most households.
• 1.5 ATA soft shell when you want the pressure the research used, in a chamber that still deflates and stores, with the option to run 1.3 or 1.4 on days you want less.
• 1.5 ATA hard shell when the chamber has a permanent room, you want everything in one cabinet with no tanks, and you want the rigid vessel that will outlast any fabric.
• 2.0 ATA and above when a physician is directing the protocol or you are outfitting a practice. These are clinical pressures and we treat them that way.

For what a session is like and how to run one safely, read best practices for hyperbaric chamber use. For the basics before any of this, start with what a hyperbaric chamber is and what it does.

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Frequently asked questions

Is 1.5 ATA better than 1.3 ATA?

It delivers more dissolved oxygen for the same concentrator, and it is the pressure most of the published research used. It also costs more, needs a heavier shell and a larger compressor. For general recovery at home, both are used. For anyone choosing a chamber because of a specific study, match the pressure the study used and talk to a physician.

Is a home hyperbaric chamber FDA approved?

Soft shell chambers are FDA cleared at 1.3 ATA for acute mountain sickness. The DeVilbiss concentrators that ship with our 1.4 and 1.5 ATA chambers are FDA approved medical devices. No home chamber is approved for recovery, sleep or wellness, and any seller who says otherwise is wrong.

Do I need an oxygen concentrator with a hyperbaric chamber?

Yes, if you want the oxygen benefit rather than pressure alone. The concentrator supplies 95 percent oxygen through a mask or cannula. Our 1.4 and 1.5 ATA chambers include one. On other chambers, confirm before you buy.

How long is a session in a home hyperbaric chamber?

Most home protocols run 60 to 90 minutes, several times a week. The chamber takes 10 to 15 minutes to reach pressure and a few minutes to come back down, and you equalize your ears on the way up the way you do on a plane.

Who should not use a hyperbaric chamber?

Anyone with an untreated collapsed lung, certain lung diseases, an active cold or sinus infection, ear surgery or ear conditions, some medications, or who is pregnant, should not use one without a physician's clearance. Claustrophobia is a real consideration in a lie-down soft shell, and the sitting and walk-in designs exist for that reason.

References

1. U.S. Food and Drug Administration. Hyperbaric Oxygen Therapy: Get the Facts. Consumer update, 2021. fda.gov
2. Undersea and Hyperbaric Medical Society. Indications for hyperbaric oxygen therapy and the definition of HBOT. uhms.org
3. Hadanny A, et al. Hyperbaric oxygen therapy improves neurocognitive functions of post-stroke patients and healthy aging adults. Aging, 2020. aging-us.com
4. Specifications and prices from the manufacturer product pages as listed at The Recovery Outlet on September 8, 2026.

Keep reading

• Soft vs Hard Shell Hyperbaric Chambers: A Practical Buyer's Guide
• What Is a Hyperbaric Chamber and What Does It Do?
• Best Practices for Hyperbaric Chamber Use

Recovery is infrastructure. Build it like one.

This article is provided for general educational purposes and does not constitute medical advice. The Recovery Outlet does not diagnose, treat, cure, or prevent any disease. Home hyperbaric chambers are not a substitute for physician-directed hyperbaric oxygen therapy. Consult a qualified healthcare provider before beginning any new wellness practice.