An ‘oxygen concentrator’ is a device that draws in outside air and purifies it for people with medical conditions that require oxygen therapy. These conditions include respiratory diseases that prevent the lungs from absorbing enough oxygen, such as chronic obstructive pulmonary disease (COPD) and asthma, as well as other conditions that affect breathing like sleep apnea and cystic fibrosis. Oxygen concentrators require a doctor’s prescription, and cannot be purchased over the counter.
Stationary oxygen concentrators have been used since the 1970s, and portable concentrators have become increasingly popular in recent years. Most models deliver air using two methods: continuous flow, which delivers air at a constant rate regardless of the user’s breathing patterns; and pulse flow, which only delivers oxygen when the user is inhaling. Portable concentrator models typically deliver one to three liters of oxygen per minute (LPM) under the continuous flow setting and one to six LPM under the pulse flow setting; they feature adjustable settings to accommodate users with different preferences. However, some models only feature pulse flow settings. Most models connect to electrical outlets for residential use, and also contain a rechargeable battery that allows them to be used away from home. Although price-points vary by brand and model, most portable concentrators sold today cost between $2,000 and $4,000.
Oxygen concentrators are an indispensable sleep aid for many people with breathing conditions because they deliver purified air throughout the night. This guide will look at portable oxygen concentrator designs and functions, as well as the top-rated concentrator models according to owners.
How Do Portable Oxygen Concentrators Work?
Prior to the 1980s, patients requiring oxygen therapy primarily relied on pressurized oxygen tanks. While these tanks are highly effective, they are also fairly inefficient; suppliers must visit patients on a regular basis to replenish the oxygen supplies in their tank(s). Patients paid suppliers for each home visit until the mid-1980s, when Medicare instituted a flat monthly rate for these services. Following these changes, the durable medical equipment (DME) industry began promoting oxygen concentrators in order to manage costs.
Oxygen concentrator units were initially tall, heavy and stationary. Portable oxygen concentrators were introduced in the early 2000s to aid patients when they were away from their homes.
As the table below explains, portable concentrators have certain advantages over pressurized oxygen tank systems. However, there is one notable disadvantage of portable concentrators: their operating time is not as long as oxygen tanks when the device cannot be plugged into an outlet and must run off of battery power.
Pressurized oxygen cylinders
Portable oxygen concentrators
5″ to 52″
7″ to 20″
1 to 114 lbs.
3 to 20 lbs.
None; tanks deliver stored oxygen by releasing valves, and do not require electrical or battery power
Electrical outlet and 1 to 2 batteries
Average Operating Time (Continuous Flow)
2 to 11 hours (lowest LPM setting) 20 minutes to 2 hours (highest LPM setting)
2.5 to 6 hours (lowest LPM setting) 45 minutes to 1.5 hours (highest LPM setting)
Average Operating Time (Pulse Flow)
5 to 30+ hours (lowest LPM setting) 1 to 6 hours (highest LPM setting)
4 to 10+ hours (lowest LPM setting) 1.5 to 4 hours (highest LPM setting)
Finite; suppliers must replenish oxygen supply on a regular basis
Infinite; concentrators draw in air, and never need to be replenished as long as they are plugged in/battery-powered and working properly
Please note: like pressurized oxygen tanks, oxygen concentrators carry a high risk of combustion. People should never smoke while using concentrators, and the device should be stored in a cool, dry place away from heat sources and flammable chemicals.
Concentrators utilize a process known as ‘pressure swing adsorption.’ All gases are adsorbed, or attracted to solid surfaces under certain pressurized settings, but the rate of attraction to various surfaces under certain pressurized settings is different for each gas. Specifically, concentrators contain zeolite minerals that attract nitrogen at a higher rate than oxygen. When the concentrator takes in air, these zeolite minerals essentially trap and contain nitrogen, which can be harmful to humans when inhaled, while a component known as a ‘molecular sieve’ allows purified, oxygen-rich air to pass through the concentrator and into the user’s breathing apparatus. Concentrators are designed to delivery oxygen at certain purity levels, usually between 87% to 96%.
Concentrators work using the following four-step process:
The concentrator draws in outside air.
The concentrator compresses the air; the device is equipped with a cooling mechanism to prevent it from overheating
Zeolite minerals attract and contain the nitrogen, while oxygen passes through the molecular sieve.
Purified oxygen is delivered to the user’s facial apparatus, which usually takes the form of nasal tubing or a face mask.
Users can adjust the airflow rate using the device’s built-in interface. Most portable concentrators can deliver oxygen at a rate of up to two or three liters per minute (LPM) under the continuous flow setting. Additionally, they may select the ‘pulse flow’ setting that only delivers oxygen when the patient is inhaling. Because the pulse flow is much more conservative than the continuous flow, the airflow rate typically ranges from one to six LPM, and some models have up to nine pulse flow settings. Higher LPM rates will drain the battery quicker, but this is a non-issue when the concentrator is plugged into an outlet. Also, please note that some concentrator models forgo the continuous flow completely and only feature pulse flow settings.
In terms of size, portable concentrators typically measure between 6 and 20 inches high, 6 and 9 inches wide, and 2.5 and 4.5 inches wide. The average portable concentrator weighs between 2 and 6 pounds, though some may weigh 20 pounds or more.
Most models list temperature and humidity level ranges at which the device can be operated and stored. Additionally, concentrators will not work properly at certain altitudes; the maximum elevation is usually 10,000 feet or higher. This figure is important for determining whether or not a concentrator is suitable for air travel, but customers should also ensure the product has been approved for use on planes by the Federal Aviation Administration (FAA).
Who Uses Portable Oxygen Concentrators?
Medical conditions that may require oxygen therapy from a concentrator include:
Bronchitis: This disorder is characterized by inflammation in the airways that lead to mucus production. Mucus buildup can cause the airways to become narrower, making it difficult to breathe.
Emphysema: Human lungs contain air sacs that inflate like balloons when you inhale and deflate when you exhale. Emphysema refers to damaged air sacs that cannot inflate and deflate properly, often leading to chronic shortness of breath.
Chronic obstructive pulmonary disorder: Also known as COPD, this disorder is essentially a combination of bronchitis and emphysema. In most cases, COPD is caused by chronic smoking.
Pneumonia: Pneumonia is an infection of the lungs that can lead to a high fever and chronic coughing. In healthy adults, pneumonia symptoms typically clear up within a couple of weeks — but the condition can be very serious, and sometimes fatal, in patients with compromised immune systems, such as young children and the elderly.
Asthma: Like bronchitis, asthma is caused by inflammation of the airways. Asthma attacks are characterized by coughing, wheezing, and chest constriction; an inhaler is usually prescribed to asthma patients.
Bronchopulmonary dysplasia: Also known as BPD, most people develop this lung infection during infancy; it is common in premature babies. The condition may be lifelong, and can lead to long-term breathing problems.
Congestive heart failure: Heart failure slows the movement of blood throughout the body, which results in insufficient oxygen flow. This condition is considered the leading health problem among elderly people in the U.S.; nearly 700,000 people are diagnosed with congestive heart failure each year.
Cystic fibrosis: This chronic lifelong condition causes thick mucus to accumulate throughout the body, including the lungs and airways. Breathing difficulty is a common symptom of cystic fibrosis.
Sleep apnea: Sleep apnea is a disorder characterized by temporary loss of breath during sleep. Obstructive sleep apnea (OSA) is caused by a physical impediment that restricts the airway and makes breathing more difficult, while central sleep apnea (CSA) occurs when the brain is unable to send the proper signals to muscles that control breathing. People with apnea may experience loss of breath more than 100 times per night, but most episodes only last a few seconds.
Regardless of the patient’s condition(s), physicians will evaluate him/or her to determine if oxygen therapy is the most suitable treatment method. They may draw a blood sample to measure the oxygen levels in the patient’s blood or use a pulse oximeter, which measures oxygen levels without requiring a blood sample. Additionally, physicians look for the following symptoms of low blood-oxygen levels:
Accelerated heart rate
Chronic shortness of breath
Chronic coughing or wheezing
Low blood-oxygen levels often necessitate oxygen therapy. The average adult has a blood oxygen concentration that sits between 75 and 100 millimeters of mercury (mmHg); people with a blood oxygen concentration of 60 mmHg or less are often prescribed oxygen therapy. Some patients require constant oxygen therapy during the day and night, while others receive therapy on a semi-frequent or as-needed basis, such as after workouts.
Oxygen Concentrators vs. CPAP and BiPAP Machines
Like concentrators, CPAP machines deliver a continuous flow of oxygen to individuals at a fixed, prescribed rate. The air is purified in the central unit, and then delivered to a face mask or nasal tubes using a connective tube. BiPAP machines utilize a similar mechanism, but rather than delivering continuous air at a fixed rate, these devices deliver oxygen at a variable rate depending on the user’s breathing patterns.
The key difference between concentrators and CPAP/BiPAP machines is the type of air that is delivered to users. Concentrators deliver purified, concentrated oxygen that is beneficial for people with the conditions listed in the previous section. CPAP and BiPAP machines, on the other hand, provide a stream of air that expands the throat muscles and keeps the airway clear. For this reason, CPAP and BiPAP machines are almost always prescribed for individuals with obstructive sleep apnea; they are not used to treat other diseases or conditions.
However, individuals with certain medical conditions — such as OSA and COPD — may use a concentrator and a CPAP or BiPAP machine simultaneously.
Buying Considerations for Portable Oxygen Concentrator Shoppers
When shopping for a portable oxygen concentrator and comparing different brands and models, here are few considerations to keep in mind:
What is the price-point? All portable oxygen concentrators are relatively expensive. The baseline price for most is $2,000. However, some high-end models cost more than $4,000.
Is the concentrator available for rent? To offset the high cost of a new concentrator, some models may be leased at monthly rates. Rental rates vary by provider, but generally fall between $200 and $350 per month.
What are the dimensions of the concentrator? Portable concentrators are usually small and lightweight, but purchasers should measure the surface where they plan to keep the concentrator (such as a bedside table) to determine the most suitable concentrator height, width, depth, and weight. For taller models, setting them on the floor next to the bed may be the most suitable option.
How much air does the concentrator deliver in continuous flow? Although this varies by model, most portable concentrators deliver anywhere from 0.5 to 3 liters per minute in the continuous flow setting.
How much air does the concentrator deliver in pulse flow? This also varies by model. The majority of portable concentrators sold today deliver up to 6 LPM in the pulse flow setting, and some feature up to three additional pulse flow settings.
What is the oxygen purity? The majority of concentrators deliver oxygen with a purity that falls between 87% and 93%. In some cases, the purity will be displayed with a margin of error (i.e., 90% ± 3%).
How long will the concentrator deliver oxygen on battery power? Generally speaking, higher settings on continuous or pulse flow will drain the battery faster than lower settings. During continuous flow, the average concentrator will deliver oxygen for up to 6 hours on the highest setting, and up to 2 hours on the lowest setting. During pulse flow, concentrators usually deliver oxygen for 1.5 to 2 hours on the highest setting, and up to 9 hours on the lowest setting.
How many batteries can the concentrator hold? Concentrators will usually hold one or two batteries. Models that hold two batteries may be operable on one battery, but the operating time will be shorter.
How long does it take to recharge the batteries? Most concentrator batteries can be completely recharged within two to four hours, but some may require up to eight or nine hours.
How loud is the concentrator? Concentrators are usually somewhat noisy, but some models are louder than others — up to 65 decibels, in some cases. The lower the setting, the quieter the concentrator will be.
What is the maximum altitude at which the concentrator can travel? Portable concentrators are designed for air travel, and most can be transported at up to 10,000 to 14,000 feet.
Has the concentrator received FAA approval? The answer to this question should always be yes, but shoppers should double-check the specs to ensure their desired concentrator has been approved for air travel by the FAA.
What are the operating and storage temperatures? Due to their delicate nature, concentrators should only be operated and stored at certain temperatures. Both ranges should be included in the concentrator’s owner’s manual or on its online product page.
What are the operational and storage humidity ranges? Owners should not operate or store their concentrator in environments that fall outside the listed humidity ranges.
Is the concentrator covered under a product warranty? Most concentrators carry a product warranty of three to five years. Additionally, certain components of the concentrator — such as the molecular sieve and/or batteries — may be protected by a separate warranty of anywhere from one to five years in length.
Do you need an oxygen concentrator? Most serious lung conditions will require some form of oxygen therapy, and a concentrator is usually more efficient and convenient than other therapy delivery systems. However, those with OSA/CSA may find that a CPAP or BiPAP machine is sufficient without supplemental oxygen therapy. Ask your doctor for more information.
Best Portable Oxygen Concentrators: Brands and Models
Next, let’s look at the best portable oxygen concentrators according to owners. The following table lists the prices, specifications, and operating details for the five top-rated concentrator models. All ratings are generated from customer and owner reviews and experiences.
For more information about sleep apnea and sleep-disordered breathing, as well as devices that sleepers can use to improve their breathing during the night, please check out the following Tuck.com pages: