Editor's Note: Oxygen concentrators require a physician's prescription to purchase. As we are not medical experts, our recommendations are based on objective features that don't affect the specifics of your oxygen therapy, such as battery life, weight and level of noise. Ultimately, the best oxygen concentrator for you depends on what your doctor prescribes and what your insurance covers.

A recent study by the American Medical Association found that over 30 million Americans have some form of chronic lung disease, and between 800,000 and 1 million of those people require some form of oxygen therapy.

As we age, lung function naturally decreases. In fact, after age 35, it’s normal to have some diminished breathing ability – your diaphragm gets weaker; lung tissue loses its elasticity; and the bones of your ribcage can change, restricting the space in which your lungs can expand.

This is further complicated by lung conditions like chronic obstructive pulmonary disease, or COPD. For elderly patients especially, respiratory infections like pneumonia or influenza can be very serious.

Given that age and disease are the main reasons for oxygen therapy, it’s reasonable to seriously consider your options before choosing a device for you or your loved one.

Best for Mobility

Best for Mobility: Caire Medical

Airsep offers true mobility with the Focus. The unit weighs just under 2 pounds and is one of the smallest portable concentrators on the market. It’s compact enough to wear clipped to your belt.

But like other compact oxygen concentrators, the Focus has some size-related drawbacks. Its two lithium-ion batteries only run for around three hours each per charge, depending on the oxygen flow rate you’re using. Each battery takes about four hours to fully charge from empty. You can buy an external power cartridge to gain 3-1/2 more hours of battery life, at a trade-off of about 8 ounces of added weight.

The Focus also lacks an option for continuous flow, as do the Inogen One G4, Invacare XPO2 and Precision, Medical PM4150 EasyPulse. It delivers oxygen in pulsed doses – small injections of oxygen released when the unit detects that you are taking a breath. If your condition requires a constant flow of oxygen, a pulsed-dose machine isn’t for you.

The Airsep Focus is on the FAA’s list of approved devices for air travel.

Best Battery Life

Best Battery Life: Inova Labs

If battery life is important to you, then the Acivox 4L is a strong contender, with a battery that can run more than 10 hours on a charge.

There are three options for transporting the concentrator, which weighs in at just under 5 pounds: a carrying case with a handle, a messenger-bag style shoulder strap and a backpack rig. The concentrator doesn’t come with a handle, but any of its carrying systems should work for most circumstances.

The streamlined interface includes purity sensors, battery life notifications and a personalized “auto mode” that helps ensure maximum absorption by monitoring changes in your activity level and adjusting accordingly. The unit’s sound output registers at a comfortable 44 dB on average.

The Activox 4L is FAA-approved for air travel. 

Best for In-Home

Best for In-Home: Nidek

The Nuvo Lite is the biggest portable concentrator on our list. It weighs in at 32 pounds and stands 23 inches tall. As we mentioned before, however, size has its advantages. In the Nuvo Lite’s case, the upsides include a high-quality molecular sieve to filter out nitrogen, recessed casters that improve durability and a moisture-reducing wick. You can also lock the flow valve so you don’t accidentally change the output rate.

While not scoring high for mobility, the unit does have wheels and a carrying handle. The Nuvo Lite may be better suited for moving between rooms in your home than it would on a long vacation.

This concentrator is not on the FAA-approved flight list.

Best Tech Support

Best Tech Support: O2 Concepts

With a straightforward interface, the OxLife Independence is a good choice if you’re not tech savvy. The concentrator’s Dynamic Network Analysis (DNA) feature connects with a team of engineers who monitor the unit and can troubleshoot it with you in real time at no extra cost. You can even track it down via GPS if you lose it. Knowing that tech support is just a phone call away can be comforting if you’re traveling and your concentrator suddenly stops working.

The Independence has better-than-average battery life, with up to nearly six hours of running time per battery (you can opt for a model with either one or two batteries) compared with three for most of the models we tested. Charge time per battery is just an hour and a half, the lowest among the 10 models we reviewed.

The unit has both pulsed and continuous-flow settings and a maximum output of 3 LPM. It’s on the heavier side, weighing it at nearly 17 pounds, but comes with large wheels that make it easier to maneuver as you move about.

O2 Concepts’ unit is on the list of FAA-approved concentrators.

Most User-Friendly

Most User-Friendly: Precision Medical

The PM4150 is one of the most user-friendly concentrators on the market. One knob controls the interface and lets you adjust the flow rate. An LED screen displays the battery status and alerts you to any malfunctions.

As the name implies, this is a pulsed-dose concentrator that will deliver doses of oxygen with every breath the unit detects. Carrying options for the 7-pound unit are a shoulder sling and a backpack. The battery offers up to three hours of runtime between charges.

The FAA has approved the PM4150 for use during air travel.

How did we research and report on oxygen concentrators?

Our editorial team researched oxygen concentrators for 30 hours. This included reading medical studies, statistics and product reviews as well as consulting with medical professionals like pulmonologists.

What is a portable oxygen concentrator used for?

A portable oxygen concentrator is a mobile version of the technology that supplies filtered oxygen drawn in from the surrounding air. Other gases, including nitrogen, are filtered out, and pure oxygen flows directly to the user.

These mobile concentrators do the same thing as home models but run on a lithium-ion battery. Battery life varies by model, but carrying multiple batteries extends how long you can use the concentrator when you are out and about.

What are the different types of oxygen concentrators?

Modern oxygen concentrators can be divided into two types: mobile and home. The mobile versions are portable, come in a variety of sizes and have varying battery length. You can buy accessories like extra batteries and carrying packs to suit the needs of your or your loved one’s lifestyle.

Home oxygen concentrators are larger and typically used by people who are more homebound. It’s worth noting there’s a big price difference between home and portable oxygen concentrators, with portables being more expensive overall. The cost of miniaturizing the technology as well as the price of batteries makes portable versions more expensive.

Do oxygen concentrators work?

Yes, the concentrator provides a flow of pure oxygen, which the bloodstream more readily accepts. This reduces strain on both the heart and the lungs. One study, “Determining the Effect on Flowrate and FiO2 of Combining the Flows From Two Oxygen Concentrators,” found that patient outcomes “improved significantly” after a course of oxygen therapy.

Are oxygen concentrators covered by Medicare?

This is a tricky question. Medicare defines an oxygen concentrator, or any medical device used for respiratory therapy, as an equipment rental. A medical equipment company rents you an oxygen concentrator and then bills Medicare a fee every month.

Where things get complicated is that oxygen equipment is limited to a 36-month rental period. Due to reimbursement guidelines, suppliers who bill Medicare are cautious about what types of equipment they rent out.

If you qualify for coverage, Medicare is required to cover you for 60 months total. However, as mentioned, oxygen equipment is limited to only 36 months of coverage. That means once your 36 months are up, the amount Medicare pays out declines sharply. For the remaining 24 months, Medicare only covers a servicing fee (one report suggests it’s around $21 a month) for the equipment you already have.

This also means that if you’re already into your 36 months of coverage and want to switch devices, you will likely be rejected because the cost of providing you with new equipment will be more than the medical device company can make by billing Medicare.

To make things even more complicated, Medicare has something called national competitive bidding. This means the companies with the best bids receive contracts to provide medical devices to an assigned region of the country. This has driven down reimbursements even more.

Medicare also only provides a flat rate payment for oxygen equipment, no matter what device you use.

How long do oxygen concentrators last?

Unfortunately, portable oxygen concentrators do not last very long. When oxygen purity drops below 80 percent, it’s advised you get a replacement unit, and that can happen between 800 and 1,500 hours. The concentrator uses zeolite crystals to filter out nitrogen, and these minerals typically last for 10 years. However, with constant use, the mechanical parts experience natural wear and tear.

Do oxygen concentrators used liquid oxygen?

No, oxygen concentrators pull oxygen from the open air and then process and filter it.

How much do oxygen concentrators cost?

Prices vary, with home concentrators typically costing less than mobile ones. Some portable oxygen concentrators cost as much as $4,000, and home models start in the $800 range. A general rule of thumb is the more you spend, the better the concentrator.

Do I need to see a doctor before getting an oxygen concentrator?

Yes, you need to see a doctor and be prescribed a device for respiratory therapy before you can buy one.

Can I buy a used portable oxygen concentrator?

Yes, buying pre-owned or refurbished oxygen concentrators is an option. Several retailers offer refurbished or pre-owned units.

Will insurance cover a portable oxygen concentrator?

Yes, private insurers cover medical devices for oxygen therapy, including portable oxygen concentrators.