An oxygen concentrator is a medical device that pulls in regular room air and removes most of the nitrogen, delivering air with a much higher concentration of oxygen through a nasal cannula or mask. Unlike oxygen tanks, which store a fixed supply of compressed oxygen, a concentrator produces oxygen continuously as long as it has power. This makes it the most common device for people who need supplemental oxygen at home.
How an Oxygen Concentrator Works
The air you normally breathe is about 21% oxygen and 78% nitrogen. An oxygen concentrator uses a process called pressure swing adsorption to separate those gases. The device draws room air through a filter, compresses it, and pushes it through columns filled with a mineral called zeolite. Zeolite acts like a molecular sieve: it traps nitrogen molecules while letting oxygen pass through. The concentrated oxygen then flows to you through tubing, while the trapped nitrogen is vented back into the room.
The device cycles between two zeolite columns in alternating phases. While one column is actively filtering nitrogen, the other is releasing its trapped nitrogen and resetting. This back-and-forth cycle happens continuously, producing a steady stream of oxygen-enriched air typically in the range of 87% to 95% purity.
Stationary vs. Portable Units
Oxygen concentrators come in two main forms, and most people who use one at home will eventually become familiar with both.
Stationary concentrators are designed to stay in one spot in your home. They weigh about 22 pounds (10 kilograms), plug into a standard electrical outlet, and deliver higher flow rates than portable models. Some brands include a battery backup or a small compressed oxygen tank so you can still receive oxygen during a power outage. These are the workhorse devices for overnight use or extended time at home.
Portable concentrators are smaller and lighter, built for moving around the house, running errands, or traveling. Most run on rechargeable lithium-ion batteries. The trade-off is lower oxygen output compared to stationary models, so they work best for people whose oxygen needs are moderate or who use them during shorter periods of activity. Many people keep a stationary unit at home and a portable unit for when they leave the house.
Conditions That Require Supplemental Oxygen
An oxygen concentrator is prescribed when a health condition prevents your lungs from absorbing enough oxygen on their own. The most common reason is COPD (chronic obstructive pulmonary disease), which gradually damages lung tissue and makes gas exchange less efficient. But several other conditions can drop your blood oxygen levels low enough to warrant a concentrator:
- Pulmonary fibrosis, where scar tissue stiffens the lungs
- Heart failure, which can cause fluid buildup in the lungs
- Cystic fibrosis
- Severe asthma
- Sleep apnea
- Lung infections such as pneumonia, COVID-19, or influenza
- Certain cancers that affect lung function
Some people use supplemental oxygen around the clock, while others need it only during sleep or physical activity. Your prescribing doctor will specify a flow rate (measured in liters per minute) based on your blood oxygen readings.
Do You Need a Prescription?
In the United States, medical-grade oxygen concentrators are regulated by the FDA and generally require a prescription. The FDA classifies oxygen devices that deliver less than 6 liters per minute (or that don’t sustain 6 liters per minute for at least 15 minutes) as prescription devices. Emergency-use oxygen equipment that meets or exceeds that 6-liter-per-minute threshold for a minimum of 15 minutes can be sold over the counter, but those are not the same as the concentrators used for ongoing therapy at home.
If you see oxygen concentrators for sale online without a prescription requirement, they may be low-output “wellness” devices not intended for treating a medical condition. For actual supplemental oxygen therapy, you’ll need a prescription that specifies your flow rate, and your insurance or Medicare will typically cover part or all of the cost.
Traveling With a Portable Concentrator
Portable oxygen concentrators are allowed on commercial flights because they don’t store or generate oxygen. They simply concentrate it from cabin air. The FAA does require you to bring enough spare batteries in your carry-on luggage to last the full duration of your flight, including potential delays. Spare batteries need to be protected from damage and short circuits, usually by keeping the terminals covered or storing them in their original packaging.
Airlines may ask for documentation of your prescription or advance notice, so check with your carrier before booking. Most major airlines maintain a list of approved portable concentrator models on their websites.
Safety Around Your Home
Oxygen itself doesn’t burn, but it makes everything around it burn faster and more intensely. The single most important safety rule: keep your concentrator and all tubing at least 10 feet away from any open flame or heat source. That includes candles, lighters, gas stoves, space heaters, wood stoves, and smoking materials. Electric razors and hair dryers also produce enough heat or sparks to be a concern.
Never smoke in a room where an oxygen concentrator is running, and don’t allow anyone else to smoke nearby. Oxygen-enriched air can saturate clothing, hair, and fabric, making them highly flammable even after the device is turned off. If you or someone in your household smokes, this is a serious fire risk that causes preventable injuries every year.
Place the concentrator in a well-ventilated area with at least a foot of clearance on all sides. The device pulls in room air and vents nitrogen, so it needs space to breathe. Don’t enclose it in a closet or drape anything over it.
Maintenance and Filter Care
Oxygen concentrators are relatively low-maintenance, but they do need regular attention to work properly. The air intake filter is the most important part to check. It catches dust and particles before they reach the internal components. Inspect it regularly for dirt buildup, wash it with warm soapy water, and let it dry completely before putting it back. In a typical home environment, filters should be replaced every 6 to 12 months. If you live in a dusty area or have pets, you may need to clean and replace them more often.
Check your nasal cannula and tubing regularly for cracks, kinks, or discoloration. Tubing that looks yellowed or feels stiff has degraded and should be swapped out. Most suppliers recommend replacing nasal cannulas every two to four weeks and tubing every one to three months, though your provider may give more specific guidance. Keeping everything clean and in good condition ensures you’re getting the full oxygen output your device is capable of delivering.