What Is an Oxygen Concentrator? A Plain-Language Guide

Last verified: October 6, 2026. An oxygen concentrator is an electrically powered machine that takes in room air, removes most of the nitrogen, and delivers the remaining oxygen-enriched air to a person who needs supplemental oxygen. Unlike a compressed gas cylinder or a liquid oxygen reservoir, it does not store a fixed supply that runs out. As long as it has power and is working normally, it keeps producing oxygen. This guide explains what an oxygen concentrator is, how it works in general terms, the main types, how it differs from other oxygen sources, and what procurement and facility teams should know.

This page is general information, not clinical or safety training. Always follow your institution’s procedures and the manufacturer’s instructions for any device.

What Is an Oxygen Concentrator?

Room air is roughly four-fifths nitrogen and about one-fifth oxygen. An oxygen concentrator draws in that air, filters it, and uses a material that preferentially holds back nitrogen so that the air leaving the machine contains a much higher share of oxygen. The user receives this oxygen-enriched air through a tube and an interface such as a nasal cannula or a mask.

The key point is that the machine manufactures its own supply from the air around it. That makes it fundamentally different from cylinders and liquid oxygen systems, which are filled elsewhere and delivered. A concentrator needs electricity (mains power or a battery) but no refills.

How an Oxygen Concentrator Works, in General Terms

Most concentrators use a process commonly described as pressure swing adsorption. In simple terms:

1. A compressor draws in room air and pressurizes it.
2. The pressurized air passes through a chamber filled with a granular material, often a type of mineral called a zeolite, that tends to hold nitrogen while letting oxygen pass.
3. The oxygen-rich gas is collected in a small reservoir and then released to the user at a controlled flow.
4. The pressure is released so the material lets go of the nitrogen, which is vented back to the room, and the cycle repeats. Machines typically use two chambers that alternate so oxygen production is continuous.

Intake filters protect the machine and the user from dust, and these filters generally need regular cleaning or replacement according to the manufacturer’s instructions. Many units include alarms for loss of power, low oxygen output, or blocked flow.

Why Oxygen Concentrators Exist

Supplemental oxygen is used for many people with lung, heart, or other conditions who cannot get enough oxygen from room air alone. Delivering that oxygen through heavy cylinders or frequent refill deliveries is costly and logistically complicated, especially for long-term home use. A concentrator removes the supply chain for the gas itself: it turns ordinary air into therapeutic oxygen on site. That is also why concentrators are common in settings where cylinder delivery is unreliable or unavailable.

Who Uses an Oxygen Concentrator

Concentrators are used at home by people on long-term oxygen therapy, in clinics, nursing homes, and long-term care settings, in some hospitals as a supplement to piped oxygen, and in remote or resource-limited facilities. Whether a person needs supplemental oxygen, and at what flow, is determined by a clinician after assessment. Oxygen is treated as a prescribed therapy, and a general guide cannot advise anyone on whether they need it or how much to use.

Types of Oxygen Concentrators

Stationary (Home) Concentrators

Stationary units are larger, plug into a wall outlet, and are designed to sit in one place, such as beside a bed or chair. They usually deliver oxygen in a continuous flow, and they can be set to a range of flow rates. Some have wheels so they can be moved from room to room. They are generally the type used for overnight and long-term use at home.

Portable Oxygen Concentrators

Portable concentrators are smaller and lighter, run on rechargeable batteries as well as plug-in power, and are designed to be carried or wheeled. Many portable units deliver oxygen in pulses that coincide with the user’s inhalation, known as pulse-dose or demand delivery, rather than a continuous stream. Some portable models also offer continuous flow. Because delivery modes differ, settings on a portable unit are not directly comparable with the flow settings on a stationary unit, and the prescriber specifies what is appropriate.

Higher-Capacity and Clinical-Use Units

Larger concentrators intended for facility use can serve more than one outlet or deliver higher flow, and some are built to be used alongside or as backup to piped oxygen systems. Specifications differ widely between models.

Common Accessories

A concentrator is only part of a working oxygen setup. Typical related items include oxygen tubing, humidifier bottles on some systems, replacement filters, a delivery interface such as a nasal cannula or mask, spare batteries and carry cases for portable models, and a backup oxygen source such as a cylinder in case of a power outage. For more on the delivery interfaces, see our guide to nasal cannula oxygen delivery, flow rates, and sizing and the overview of CPAP and oxygen mask types.

How an Oxygen Concentrator Differs from Related Equipment

• Concentrator vs. oxygen cylinder. A cylinder stores a finite amount of compressed oxygen that is eventually used up and has to be refilled or replaced. A concentrator makes oxygen continuously from room air but requires power.
• Concentrator vs. liquid oxygen. Liquid oxygen systems store oxygen in a very cold liquid form in a reservoir that is refilled by a supplier. A concentrator needs no supplier deliveries.
• Concentrator vs. ventilator. A concentrator is an oxygen source. It does not push air into the lungs or support breathing effort. A ventilator is a machine that assists or takes over the work of breathing and can itself be supplied with oxygen.
• Concentrator vs. CPAP machine. A CPAP device delivers pressurized room air to keep the airway open. It is not an oxygen generator, although some setups add oxygen to the circuit under a clinician’s direction.
• Concentrator vs. pulse oximeter. A pulse oximeter measures how much oxygen the blood is carrying. A concentrator supplies oxygen. They are often used together, but one measures and the other delivers.

Practical Relevance for Research Administration and Procurement

For people who source, budget for, or oversee equipment, oxygen concentrators bring a distinctive mix of equipment and consumable considerations.

First, they are durable equipment rather than single-use items, so the relevant questions include service life, maintenance schedules, warranty terms, and who is responsible for servicing. Filters and tubing are the recurring consumables.

Second, power dependence is a planning issue. Facilities and home programs generally need a backup oxygen source for outages, and portable units need battery management. Contingency planning is part of the total cost of ownership.

Third, specifications matter. Maximum flow, delivery mode (continuous or pulse), noise level, weight, and alarm features differ by model, so buyers usually work from a clinical specification rather than choosing on price alone. Output concentration is typically stated by the manufacturer and can fall as flow settings rise, so published specifications should be read carefully.

Fourth, oxygen equipment is regulated, and oxygen supports combustion, so safety rules about open flames and smoking around oxygen apply in any setting where it is used. Facilities generally keep service records and follow equipment management programs, and coverage and reimbursement rules for home oxygen vary by payer; our overview of Medicare DME coverage is a starting point for how durable medical equipment is treated.

Frequently Asked Questions

What does an oxygen concentrator do?

It takes in room air, removes most of the nitrogen, and delivers oxygen-enriched air to a person who needs supplemental oxygen, without needing refills of stored gas.

Is an oxygen concentrator the same as an oxygen tank?

No. A tank stores a limited amount of compressed oxygen that eventually runs out. A concentrator produces oxygen from room air as long as it has power.

What is the difference between a stationary and a portable concentrator?

Stationary units are larger, run on mains power, and typically deliver continuous flow. Portable units are lighter, battery-capable, and often deliver oxygen in pulses timed to breathing, though some also offer continuous flow.

Does an oxygen concentrator need electricity?

Yes. It needs mains power or a charged battery to run. That is why a backup oxygen source is commonly planned for in case of power loss.

Can anyone use an oxygen concentrator?

Supplemental oxygen is a prescribed therapy, and the right flow and delivery mode are determined by a clinician. Using oxygen without that guidance is not recommended.

Is an oxygen concentrator noisy?

Most produce some operating noise from the compressor and valves, and the level varies by model and flow setting. Noise ratings are usually listed in manufacturer specifications, which matters for bedroom and clinic placement. Portable units are often quieter at low settings but can be audible when running at higher output.

Can a concentrator be used in a hospital?

Some hospitals and clinics use concentrators as a supplement or backup to piped oxygen, particularly in outpatient and long-term care areas. Whether and where they are used is set by facility policy and biomedical engineering review.

Does a concentrator need maintenance?

Yes. Intake filters, tubing, and cannulas generally need cleaning or replacement on a regular basis, and the unit may need periodic servicing. The manufacturer’s instructions and facility policy set the schedule.