Best Continuous Flow Portable Oxygen Concentrators

By Hillary Eames
Medically Reviewed by Amber Snow, MSN, APRN, AGPCNP-C
Reviewed by Kathleen Cameron, BSPharm, MPH, Senior Director, NCOA Center for Healthy Aging
Fact Checked

• Continuous flow oxygen concentrators deliver a constant stream of oxygen either through an oxygen mask or nasal cannula.
• Continuous flow portable oxygen concentrators are often dual flow, which means you can choose between pulse or continuous flow for oxygen delivery.
• We researched both continuous flow portable oxygen concentrators and continuous flow home oxygen concentrators to meet all oxygen delivery needs.

Oxygen concentrators can deliver oxygen in three ways: pulse flow, continuous flow, or both. Continuous flow portable oxygen concentrators offer a consistent flow of oxygen, while pulse flow portable oxygen concentrators provide oxygen every time you inhale, according to an article published in the journal Breathe.¹ Continuous flow oxygen is often recommended for people who require a high oxygen flow, which is roughly 3 liters per minute or more, according to the American Thoracic Society.² Ask your doctor if you would benefit from a high-flow oxygen concentrator.

Most portable oxygen concentrators offer both pulse dose and continuous flow delivery. If your health care provider has recommended a continuous flow portable oxygen concentrator, you have options. Our Reviews Team compared top brands to help you find the best fit for your oxygen needs and lifestyle.

• Best Battery Life: O2 Concepts Oxlife Independence
• Most Versatile: CAIRE SeQual Eclipse 5
• Most Lightweight: Respironics SimplyGo

Our Reviews Team recommends products and services we believe provide value in the lives of our readers. We’ve spent more than 1,000 hours carrying out in-depth research on portable oxygen concentrators to give you the most accurate review.

To make our selections, we’ve done the following:

• Engaged in independent research
• Consulted with three geriatric care experts
• Mystery shopped four brands and five models of portable oxygen concentrators
• Reviewed academic research into the efficacy of portable oxygen concentrators
• Read real reviews from verified customers on trusted third party sites, including the Better Business Bureau (BBB) and Trustpilot

Our Reviews Team consulted with three geriatric care experts to learn more about portable oxygen concentrators (POCs) and home oxygen concentrators (HOCs), as well as how they can enhance users’ quality of life. Based on our expert consultations and research, we determined the following factors to be important for our readers when shopping for a POC or HOC unit:

• Cost
• Ease of use
• Oxygen delivery method
• Number of settings
• Weight and size
• Battery life (for POCs)
• Time to recharge battery (for POCs)
• Power usage (for HOCs)
• Oxygen purity (for HOCs)
• Availability (all devices available online or in brick-and-mortar stores)

We had experts in the field medically review all of our selections to ensure that each brand and model is appropriate for our readers’ needs.

Pros

• Battery life of more than five hours on continuous flow setting 1, the longest of any portable oxygen concentrator on this list
• Comes with two batteries, AC adapter, and DC adapter
• Five-year warranty
• FAA approved

Cons

• Built-in cart and six-inch wheels could make the concentrator awkward to transport
• Only goes up to 2 liters per minute on continuous flow, which may not be enough for some prescriptions

Cost: $2,850

Weight: 16.7 pounds

Dimensions: 10.9 inches long x 8 inches wide x 20.2 inches high

Range of flow settings: 0.5–3 continuous; 8–96 milliliter pulse (settings 1–6)

Battery life (setting 1): 5.25 hours

Battery charging time: 1.5–2.5 hours

Maximum oxygen output: 3 liters per minute

Noise level: 40 decibels

Warranty: Five years

In this O2 Concepts unit, the battery lasts 5.25 hours on setting 1. On setting 3, it lasts 1.5 hours, which is the highest setting for portable continuous flow oxygen. For comparison, the Respironics SimplyGo lasts 1.6 hours using the lowest setting for receiving continuous oxygen, setting 1. This means that the battery life of the O2 Concepts on its highest setting is similar to the Respironics battery on its lowest.

The O2 Concepts Oxlife Independence portable oxygen concentrator also has an AC/DC adapter that allows you to use it while charging. The DC charger is integrated into the unit, meaning you don’t have an external power cord brick. The custom two-battery configuration allows you to remove one battery if you’d like a more lightweight continuous flow portable oxygen concentrator or install both batteries for longer battery power.

This unit is larger than some, at 20 inches high and nearly 17 pounds, but it does come with wheels and a handle for more convenient transport. The noise level of 40 decibels is about the same as the hum of a refrigerator, according to the Centers for Disease Control and Prevention (CDC).³

Customer service

The O2 Concepts Oxlife Independence continuous flow portable oxygen concentrator is available for purchase from online retailers such as the Oxygen Concentrator Store and some local durable medical equipment stores. You can also buy the concentrator from the store in Denver, Colorado.

Payment options

You can use the following methods to pay for this continuous flow oxygen concentrator:

• Cash (in store only)
• Credit card
• CareCredit
• PayPal
• Affirm

Pros

• Has a carrying cart with wheels and collapsible handle as well as a carrying bag and accessory bag
• AutoSAT technology maintains consistently sized doses of oxygen regardless of pulse setting or power supply (pulse mode only)⁴
• Powerful rechargeable battery, AC power supply adapter, and DC power adapters
• Continuous flow doses in half-increments for precision
• FAA approved

Cons

• Most expensive on the list at $3,200
• Small window display on the control panel may be difficult to read

Cost: $3,200

Weight: 18.4 pounds

Dimensions: 7.1 inches long x 12.3 inches wide x 19.3 inches high

Range of flow settings: 0.5–3 continuous; 16–192 milliliter pulse (settings 1–9)

Battery life (setting 1): 3.7 hours on continuous; 5.7 hours on pulse

Battery charging time: 1.8–5 hours

Maximum oxygen output: 3 liters per minute

Noise level: 48 decibels

Warranty: Three years

If your oxygen prescription allows for flexibility between pulse and continuous delivery, the CAIRE SeQual Eclipse is a great choice. This unit has half-liter increments available for both continuous and pulse flows, helping to meet very precise oxygen needs.

The DC adapter allows the oxygen machine to be used (and charged) in some vehicles. You can easily remove the battery and recharge it when necessary. The concentrator also comes with a carrying bag and cart, which could make moving this unit easier, as it’s one of the larger and heavier choices of portable oxygen concentrators on the list. At 48 decibels, its noise level is similar to that of a refrigerator while running.

Customer service

The CAIRE SeQual Eclipse 5 continuous flow portable oxygen concentrator is available for purchase from online retailers such as the Oxygen Concentrator Store or some local durable medical equipment stores.

Payment options

You can use the following methods to pay for this continuous flow oxygen concentrator:

• Cash (in store only)
• Credit card
• CareCredit
• PayPal
• Affirm

Read more in our dedicated CAIRE review.

Pros

• Small and lightweight
• FAA approved for air travel
• Quiet
• Simple, easy-to-navigate control panel

Cons

• Shortest battery life on this list
• Only goes up to 2 liters per minute on continuous flow, which may not be enough for some prescriptions

Cost: $2,500

Weight: 10 pounds

Dimensions: 10 inches long x 6 inches wide x 11.5 inches high

Range of flow settings: 0.5–2 continuous; 12–72 milliliter pulse (settings 1–6)

Battery life (setting 1): 1.6 continuous, 3.4 pulse

Battery charging time: 2–3 hours

Maximum oxygen output: 2 liters per minute

Noise level: 43 decibels

Warranty: Three years

Our Reviews Team selected the Respironics SimplyGo portable oxygen concentrator as the best lightweight, portable oxygen concentrator because, at only 10 pounds and standing less than 1 foot tall, it’s easier than comparable units to carry with you.

According to a 2023 survey conducted by our Reviews Team, the use of portable oxygen concentrators improved 44% of respondents’ ability to socialize outside their home.⁵

A lightweight unit can give users more freedom, including the ability to travel more easily. The Respironics SimplyGo is also approved by the Federal Aviation Administration, meaning you can take it with you on airplanes. The noise level of this unit is 43 decibels, similar to the hum of a refrigerator.

Customer service

The Respironics SimplyGo continuous flow portable oxygen concentrator is available for purchase from online retailers such as the Oxygen Concentrator Store and some local durable medical equipment stores.

Payment options

You can use the following methods to pay for this continuous flow oxygen concentrator:

• Cash (in store only)
• Credit card
• CareCredit
• PayPal
• Affirm

Dive deeper with our full Philips Respironics review.

If your oxygen needs are higher than what a constant flow portable oxygen concentrator can accommodate, a home oxygen machine may be right for you.

Home oxygen concentrators only provide continuous oxygen flow, while portable oxygen concentrators with continuous flow will also offer pulse flow. If your doctor recommends more than 3 liters of oxygen per minute, you may benefit from a continuous flow home oxygen concentrator instead of a portable one.

Looking to shop for a home oxygen machine? Both of the below units deliver up to 5 liters of continuous flow oxygen per minute.

• Most Affordable: CAIRE Companion 5
• Easiest to Use: Inogen At Home 5

Pros

• AutoFLOW technology reduces power when the oxygen machine is operating at 2 liters per minute, going from 350 watts–250 watts
• Doses oxygen in half-liter increments for precise oxygen delivery
• Large, highly visible control panel

Cons

• Heaviest 5-liter oxygen concentrator on this list
• May be noisy on higher settings (50+ decibels)

Cost: $695

Weight: 36 pounds

Dimensions: 12.5 inches long x 13.5 inches wide x 21.5 inches high

Power usage: 350 watts max

Maximum oxygen output: 5 liters per minute

Oxygen purity: 85–95%

Noise level: 50 decibels

Warranty: Three years

We selected the CAIRE Companion 5 as our most affordable option for a 5-liter continuous flow oxygen concentrator at $695. This stationary oxygen concentrator offers high levels of oxygen purity and precise oxygen dosing, as well as an easy-to-use control panel and a small, mobile design. Despite its ease of use, it’s 36 pounds, which might make it difficult to move around the house for some. The noise level of 50 decibels means that it will sound a little quieter than an air conditioner while operating.

Customer service

The CAIRE Companion At Home 5 continuous flow portable oxygen concentrator is available for purchase from online retailers such as the Oxygen Concentrator Store some local durable medical equipment stores.

Payment options

You can use the following methods to pay for this continuous flow oxygen concentrator:

• Cash (in store only)
• Credit card
• CareCredit
• PayPal
• Affirm

Pros

• Small and lightweight
• Simple control panel
• Requires minimal maintenance

Cons

• May be awkward to move from room to room (18 pounds and no wheels or handles)
• Expensive at $1,500

Cost: $1,500

Weight: 18 pounds

Dimensions: 13 inches long x 7 inches wide x 16.5 inches high

Power usage: 275 watts

Maximum oxygen output: 5 liters per minute

Oxygen purity: 87–96%

Noise level: 40 decibels

Warranty: Three years

This oxygen machine by Inogen is designed for ease of use. It’s a 5-liter continuous flow oxygen concentrator with a three-button control panel.  It’s very quiet at only 40 decibels, which is about the same as the hum of a refrigerator. The small, slim design makes it easy to fit next to a desk, chair, or nightstand.

Customer service

The Inogen At Home 5 continuous flow portable oxygen concentrator is available for purchase from online retailers such as the Oxygen Concentrator Store and some local durable medical equipment stores.

Payment options

You can use the following methods to pay for this continuous flow oxygen concentrator:

• Cash (in store only)
• Credit card
• CareCredit
• PayPal
• Affirm

The staff at Oxygen Concentrator Store are always courteous and friendly when our Reviews Team speaks with them. They are knowledgeable about the available products and the needs of their customers, and they are eager to answer any questions. When our Reviews Team filled out the online form to request a price for a portable oxygen concentrator, a sales representative called within a couple of hours. We also received three emails after submitting our online price request: one from the same sales representative introducing himself, a second offering a download of the catalog, and a third featuring some of the bestselling portable and home oxygen concentrators.

The website gives you the opportunity to learn more about your personal sales representative. They are referred to as Oxygen Therapy Specialists, and the website offers a full biography of their work experience alongside customer reviews.

Oxygen Concentrator Store uses UPS Ground for standard shipping to all 50 states. Shipping typically takes two to five business days, but they also offer two-day and overnight shipping options. You will need to speak with a specialist at Oxygen Concentrator Store for specific shipping cost information. All purchases from Oxygen Concentrator Store come with a customer satisfaction policy that includes a 14 day return or exchange window. If you are unsatisfied with the unit when it arrives, you can call the store to receive a shipping label to send it back within 14 days of receipt of order. You will have to pay for the return shipping.

Oxygen Concentrator Store does not bill Medicare directly for rentals or supplies.

Continuous flow oxygen concentrators deliver the same consistent amount of oxygen. This makes them different from pulse flow oxygen concentrators. Pulse flow concentrators deliver a small dose, or “pulse,” of oxygen every time you take a breath. If your breathing rate increases, a pulse flow portable oxygen concentrator will respond with a higher flow rate by delivering more oxygen to meet your body’s needs. Between each inhalation, the machine doesn’t deliver oxygen. A continuous flow oxygen machine will give the same amount of oxygen no matter what—your breathing rate doesn’t affect delivery.

“Pulse flow is best described as drinking water with a straw, where the delivery is more controlled and individualized per need,” explained Danielle Jason, an oxygen specialist, in a blog post she authored for the Oxygen Concentrator Store. “A continuous flow machine is [more like] drinking water out of a water fountain. When you turn on a water fountain, water streams out at a somewhat steady pace.”⁶

Continuous flow oxygen delivery is the most common form of oxygen delivery. Home oxygen concentrators offer only continuous flow, while many portable oxygen concentrators offer the option to choose between pulse or continuous flow oxygen delivery. Currently, there aren’t any POCs that deliver portable oxygen with continuous flow only; POCs are either dual flow or pulse flow only.

To maintain your oxygen concentrator, you will typically need to clean two parts of the unit. The air intake or particle filter—which keeps dust, pollen, and other airborne particles out of your oxygen—needs weekly cleaning with mild soap and water. The outside of the machine can also be cleaned with a damp cloth approximately once a week. Follow the directions in the user manual included with your unit for exact instructions on cleaning and maintenance.

Continuous flow portable oxygen concentrators or home oxygen concentrators may be right for people with higher oxygen needs. Continuous flow oxygen machines can provide more oxygen than pulse flow machines. One study that compared the amount of oxygen inhaled with continuous flow versus pulse flow found that the continuous flow method provides more oxygen with each inhale.⁷

Some conditions that may benefit from continuous flow oxygen concentrators include chronic obstructive pulmonary disease (COPD), pneumonia, COVID-19, cystic fibrosis, and late-stage heart failure.⁸

If you have sleep apnea, your doctor may recommend using continuous flow oxygen machines while you sleep. This is because they won’t sound an alarm if your breathing becomes shallow or if you breathe through your mouth instead of your nose. Pulse flow machines have alarms that go off if you don’t inhale or the machine can’t detect a pulse. The device may not be able to detect shallow or mouth breathing, and that might set off the alarm.

Home oxygen concentrators are generally less expensive than portable oxygen concentrators. A continuous flow portable oxygen concentrator will cost approximately $2,000–$4,000, while a continuous flow home oxygen concentrator may cost approximately $700–$2,000. This will depend on the brand and model of the oxygen concentrator you select. For a more budget-conscious choice, you can also choose to rent a continuous flow portable oxygen concentrator.

Does Medicare cover continuous flow portable oxygen concentrators?

Medicare covers continuous flow oxygen concentrators, both portable and stationary, under Medicare Part B. Oxygen concentrators are considered durable medical equipment. With Medicare Part B, you are able to rent a continuous flow portable oxygen concentrator or stationary oxygen concentrator for 36 months. After 36 months, your oxygen supplier is required to continue supplying oxygen equipment and supplies for at least another 24 months, up to a total of five years.

After you meet your Medicare Part B deductible, Medicare will pay for 80% of your continuous flow portable oxygen concentrator rental. Alternatively, if you choose to buy your own equipment, Medicare will also help pay for oxygen and supplies.⁹

Does insurance cover continuous flow oxygen concentrators?

Insurance coverage will vary from carrier to carrier. Most insurances will cover continuous flow oxygen concentrators as durable medical equipment, either by helping pay for part of them as a purchase or helping with rental costs as Medicare does. If you are unsure of your insurance coverage, we recommend reaching out to your insurance provider.

Many portable oxygen concentrators offer both a pulse flow and a continuous flow delivery setting. The O2 Concepts Oxlife Independence is best for those who want a portable oxygen concentrator with continuous flow and long battery life. The most versatile unit on our list is the CAIRE SeQual 5, which comes with multiple features that make it convenient to use. And the Respironics SimplyGo is the lightest, which is important for those who want to improve or maintain their mobility and ability to participate in social activities.

Home oxygen concentrators always offer continuous flow delivery, which is why we also included them on our list. The easiest to use is the Inogen At Home 5, and the most affordable is the CAIRE Companion 5.

While you have multiple factors to consider when selecting a continuous flow oxygen concentrator for supplemental oxygen, whether it’s portable or stationary, you can find an oxygen machine that will fit your prescription, goals, and lifestyle.

Have questions about this review? Email us at reviewsteam@ncoa.org.

1. Georgia Hardavella et al. Oxygen devices and delivery systems. Found on the internet at https://www.ucsfhealth.org/education/your-oxygen-equipment#1
2. Annals of the American Thoracic Society. Patients Choose Hypoxia Over Social Isolation. Found on the internet at https://www.atsjournals.org/doi/full/10.1513/AnnalsATS.202106-676ED
3. What Noises Cause Hearing Loss? Centers for Disease Control and Prevention. Found on the internet at https://www.cdc.gov/nceh/hearing_loss/what_noises_cause_hearing_loss.html
4. Eclipse with autoSAT manual. Oxygen Concentrator Store. Found on the Internet at https://www.oxygenconcentratorstore.com/manuals/portable/sequaleclipse5/Eclipse%205%20Manual.pdf
5. NCOA Advisor POC Survey. 600 respondents. Conducted using Pollfish. Launched January 5, 2023.
6. Pulse vs. Continuous Flow. Oxygen Concentrator Store. Found on the internet at https://www.oxygenconcentratorstore.com/blog/pulse-vs-continuous-flow
7. John Chen et al. Comparison of pulsed flow from portable oxygen concentrators with continuous oxygen delivery. Found on the internet at https://erj.ersjournals.com/content/52/suppl_62/PA3341
8. National Library of Medicine. Oxygen Therapy. Found on the internet at https://medlineplus.gov/oxygentherapy.html
9. Medicare. Oxygen Equipment and Accessories. Found on the internet at https://www.medicare.gov/coverage/oxygen-equipment-accessories