What’s the Difference Between an Oxygen Concentrator and Oxygen Tank?

Oxygen is quintessential for our being. When one has a respiratory condition and breathing is adversely affected, a doctor prescribes supplemental oxygen to aid the oxygen intake. When we think of supplemental oxygen solutions, a traditional bulky oxygen tank often comes to the mind. Nonetheless, oxygen delivery technology is ever evolving and has made several advances in the last few years. The two widely used oxygen delivery mechanisms at home are oxygen tanks and oxygen concentrators. We’ll discuss below what they are and how they differ so that you can make an informed decision about your choice of oxygen delivery.

How Do Oxygen Tanks Work?

Oxygen tank is the most prevalent way to deliver medical-grade oxygen to the patients. Oxygen tanks or cylinders are generally made of steel or aluminum. There are two kinds of oxygen tanks – one contains compressed oxygen, and another contains liquid oxygen.

The oxygen is extracted from the air and compressed at a very high-pressure of 2,200 PSI to be stored in tanks. Since these tanks are high pressured, the oxygen is delivered through a regulator to maintain the required oxygen flow rate.

Whereas to create liquid oxygen, the gaseous form of oxygen is cooled at -297°F. It is stored in special vacuum insulated containers to maintain the liquid state of the oxygen. Liquid oxygen takes up significantly less amount of storage space. One liter of liquid oxygen is equivalent to 860 gaseous liters. When the liquid oxygen is exposed to the room temperature it quickly converts to its gaseous form, ready to be consumed.

Per the United States Pharmacopoeia (USP) standards, oxygen tanks or cylinders must not have less than 99% oxygen purity. Usually, the compressed oxygen and the liquid oxygen are stored at a 99.5% purity level.

Oxygen Tanks and Liquid Oxygen

How Do Oxygen Concentrators Work?

Oxygen concentrators (or oxygenators) differ significantly from traditional oxygen tanks since they do not store oxygen. Regular air is made up of 78% nitrogen, 21% oxygen and 1% other gases. An oxygen concentrator receives the ambient air, filters out nitrogen to retain oxygen, and then supplies it through the nozzle. Oxygen concentrators are usually capable of delivering 90 to 95 percent pure oxygen.

They deliver air in a continuous or intermittent flow. Continuous flow oxygen concentrators provide a consistent amount of oxygen regardless of how many times a patient breathes per minute. In contrast, intermittent flow (also known as pulse flow) delivers oxygen in periodic air bolus. Pulse-flow capable oxygen concentrators detect the user’s breath and deliver oxygen right when they inhale.

Size and Weight

Oxygen cylinders and tanks vary in size and capacity. The commonly used E type cylinder can deliver 680 liters of oxygen when full (at 2015 PSI). With this capacity, the tank is capable of delivering oxygen for over five hours at a flow rate of 2 liters per minute. This cylinder is over two feet in length and weighs almost 8 pounds.

The most critical factor that determines which size of an oxygen tank to go for is the user’s oxygen requirement. On a high oxygen flow requirement, H or M250 tanks are advised. These large tanks are stationary and weigh around 120 pounds.

In the case of liquid oxygen, specially designed oxygen reservoirs are required since oxygen in liquid form is very cold. A nasal cannula can be hooked to the reservoir to fulfill the oxygen need at home. The liquid oxygen reservoirs are big and not mobile. Besides, liquid oxygen can be delivered at a higher rate of flow for a much longer period than a compressed gas system. However, liquid oxygen is much more expensive than gas.

Portable Oxygen Concentrators are considerably small and light. The smallest portable device is Inogen One G4 and it weighs 2.8lbs only. At a setting of 2, it can last over 4 hours on a double battery. These devices are made by keeping in mind the active lifestyle needs of the patients.

Home oxygen concentrators are meant for in-house usage and can provide oxygen at up to 10 liters per minute on a continuous flow. Therefore, these devices are larger than portable oxygen concentrators and weigh around 30 pounds. Nevertheless, they have wheels at the bottom and can be moved easily to any room in your house. These units are as loud as a humming refrigerator. If it bothers you, the device can be set up in a separate room with a length of tubing that allows the patient mobility around the home.


Oxygen tanks such as type A, B, C, D, JD, and E are portable. They can be carried around in and out of your house. Some of these tanks come with a cart to carry around.

Liquid oxygen can be used outside the house with the help of a portable liquid oxygen container. Liquid oxygen can be transferred to this smaller container from the storage tank. Many of these smaller portable containers can deliver oxygen for up to 10 hours, depending on the capacity and consumption.

Portable oxygen concentrators (POC), as the name suggests, are highly portable. They run on battery and make their own oxygen, so they can be taken anywhere. Of course, not in water and at extreme temperatures. POC comes with a DC charger that means you can charge the unit in your car, RV, or boat using the cigarette lighter. POC can be slid into a messenger-bag style carrying case or carried around in a tailor-made backpack or a cart.

Not only that, portable oxygen concentrators are TSA and FAA approved, allowing them to be used on a flight. They are allowed on airplanes as long as they are FAA approved, have sufficient battery, and can fit under a seat or in an overhead compartment. Oxygen concentrators can be rented for travel use.

Flying with a Portable Oxygen Concentrator


Oxygen tanks need to be refilled or exchanged from the provider weekly or biweekly, depending on the consumption. This not only means you have to be at the home when the provider visits but also that it’s a recurring expense.

Home Oxygenators do not require refilling. This is a major advantage because the user doesn’t have to be concerned with changing the tank when the oxygen runs out. They do, however, require a power source. Learn how much a concentrator add to your electricity bill. Patients who require continuous oxygen or a high flow rate will find concentrators advantageous because they never run out of oxygen.

Portable oxygen concentrators also do not require refilling or calling the provider regularly. You don’t have to be home at a fixed time or worry about carrying the tanks in and out. POCs are battery-powered and come with adapters so that they can be plugged into an AC or DC power source when the battery is low.

Some Other Important Points

Compressed Oxygen Tanks

  • Oxygen tank needs to be handled with care and kept upright
  • Oxygen tanks have to be changed multiple times in a day, when empty
  • The pressure valve attached to oxygen tanks must be checked consistently
  • Pressurized oxygen is a fire hazard and appropriate measure must be taken for safe storage

Liquid Oxygen

  • Like gas, liquid oxygen containers need to be kept level
  • The bottle attached to the reservoir to collect condensed water needs to be emptied regularly
  • When mishandled while filling the portable tank, it can cause frostbite burns to the skin

Oxygen Concentrator

  • Oxygen concentrators feature several alerts to make sure you get the required oxygen
  • They are more expensive up-front but in the long term they cost less than oxygen tanks

Final Thoughts

When choosing between a traditional oxygen tank and oxygen concentrator, there are many things to take into consideration. These include how much oxygen the patient has been prescribed, how often he or she will leave home and what types of activities will be engaged in. You should also consider how much the unit weighs and balance that with personal strength so that the oxygen tank or concentrator can be moved with ease when necessary. Finally, you may want to choose a system that can grow with you if you anticipate that your oxygen needs may increase in the future.

Related Information


Updated: March 18, 2020
Published: May 11, 2016

About Scott Ridl: Scott joined American Medical Sales and Rentals in 2008 as a Web Manager and Content Writer. He is a writer and designer. He is extensively trained on oxygen therapy products from leading manufacturers such as Inogen, Respironics, Chart, Invacare, ResMed and more. Scott works closely with respiratory therapists and oxygen specialists to educate the community about oxygen therapy products, COPD, asthma and lung diseases. He writes weekly columns and is passionate about educating the community on oxygen therapy and respiratory issues.

38 thoughts on “What’s the Difference Between an Oxygen Concentrator and Oxygen Tank?”

  • Adolf H.

    Why Oxygen concentrated is 87%?

    • Danielle Jason
      Danielle Jason March 23, 2017 at 2:03 am

      Medical grade oxygen is considered any concentration of oxygen above 85%. Oxygen concentrators will provide anywhere from 90% to 95% pure oxygen while running properly.

  • Eileen

    Pleas send me estimate of considerate stationary and portable for travel in oxygen .Right now I use the tanks and I am at #2 and I was told that near future I will be going up on the number that why I want to pay once.Thank You Eileen

    • Danielle Jason
      Danielle Jason March 28, 2017 at 1:43 am

      Hello Eileen, thank you for your comment. Go ahead and give our Oxygen Specialists a call at 888-360-9879 and they'll work with you to find a stationary and portable unit to fit your needs.

  • Harper Campbell

    My grandmother has recently been put on an oxygen support, and we need to decide which method would be the right one for her once she leaves the hospital. It's interesting to know that the concentrators that there are two kinds that we can get, the large unit for the house and smaller ones to making it easy to carry around. I like how you also made the point that this will allow a consistent amount of oxygen regardless of how much she breaths per minute.

    • Danielle Jason

      Thank you for your comment, Harper. Do not hesitate to reach out should you have any further questions regarding your grandmothers oxygen support. We've also passed along your information and will have someone reach out via email with some further information.

  • ellen skinner

    are there payment plans available

    • Danielle Jason

      Absolutely, Ellen. For information regarding payment plans please contact one of our Specialists at 877-774-9271.

  • Ericka Mae Bayona Mangahas
    Ericka Mae Bayona Mangahas October 1, 2017 at 6:38 pm

    Hi there! My mom is currently using oxygen tank at home. She is having a lung complication. Her oxygen tank is 15 lbs. She uses 2x a day that's why she needs 30 lbs a day. just want to ask if oxygen concentrator is good for her?

    • Danielle Jason

      Hello Ericka, thank you for your comment. If you'd like you can reach out to one of our Oxygen Specialists at 877-774-9271. They will be able to work with you to find the right solution for your mother and her condition.

  • Louise knepple

    How many hours can I get if I am at 4Is
    I am going to a meeting and am not sure of access to an outlet Ihave a portable and need more time for this event Is there a bigger battery pack or a bigger unit that I can rent for theday

    • Danielle Jason

      That is a great question, Louise. The answer all depends on the type of unit you have. If you'd like you can give one of our Oxygen Specialists a call at: 877-774-9271 and they can walk you through your available options.

  • Cynthia

    Are their filters, water etc, maintenance on an oxygenator?

    • Danielle Jason

      That's a great question, Cynthia. The components of oxygen concentrators do vary based on the model and brand. There are many oxygen concentrators that do have filters, humidifier attachments, and required maintenance. Is there a brand in particular you are looking at? Feel free to give one of our Oxygen Specialists a call to discuss your options at 877-774-9271.

  • Mary Jo cappuccilli
    Mary Jo cappuccilli November 13, 2017 at 11:12 pm

    Hello. When the concentrator is turned off, is there no oxygen stored in the system?

    • Danielle Jason

      Thank you for your comment, Mary. When the concentrator is turned off it will not be producing oxygen. Check out our page here: https://www.oxygenconcentratorstore.com/reference-material/how-concentrators-work/ for an in-depth breakdown of how oxygen concentrators operate

  • Mel

    I use a machine for concentrated oxygen. I use it every night. Today I see an ad on the Internet about liquid oxygen drops that can be dropped into you water or other beverage. It is somewhat expensive but makes you feel that it is the bet thing you can use for oxygen therapy. It speaks about feeling different the same day or two, etc. Which is better, the liquid for 50 bucks or the machine my doctor recently sent to my home and was paid for by Medicare. It is on wheels and sits next to my bed. The machine itself produces heat in the room, comfortable enough to not have to always use central heating. The ad claims this liquid oxygen can almost cure anything, which is hard to believe. I cannot remember the name of it now, but can you send me some information about the concentrated oxygen vs. the liquid oxygen which calls for three drops a couple times a day. I have not talked to my doctor, not until my next appointment in four weeks. He just prescribed the machine and had it sent to me and always said I do not have enough oxygen in my blood. Will this concentrated oxygen help to possible reduce the cancer that has been found in my prostate gland though surgical biopsy? I am 77 and have diabetes which gives me low testing numbers. Thanks for your help. Mel Toadvine, [email protected]

    • Danielle Jason

      Thank you for your comment, Mel. We suggest, as always, consulting your physician regarding finding an oxygen solution that is right for you.

    • Natasha

      You cannot put liquid oxygen in a bottle and put drops in your drink. That supplier should be shot. Liquid oxygen is liquid because it is extremely, extremely concentrated. First, the bottle would break. Second, say you had an aluminum bottle. When you opened the top, the oxygen would expand and yo would have a lot of oxygen in the room but not in an eye dropper.

      Really, Ms Jason could have answered that!

  • Rose Rafferty

    My mom needs oxygen but from experience with it in hospitals is not willing to agree because it makes her nose and throat so dry that her nose bleeds and she cannot eat or drink. Do the concentrators retain the humidity in the air or is the humidity removed when the oxygen is concentrated and cleaned?

    • Margaret Goodman
      Margaret Goodman March 26, 2019 at 5:38 am

      You can add a humidifier to some of the concentrators and there are also solutions for dry nose and throat as well. We have a great blog post you can read here about it https://www.oxygenconcentratorstore.com/blog/prevent-dry-nose-throat-mouth-oxygen/

  • Cathy

    Which unit can be used with an O-Zone device please?

  • Dean

    Mom needs oxygen. When on tank oxygen she keeps her numbers up. When on a Concentrator the oxygen level drops. Is there a reason why?

  • Johnie Wood

    I tried to discuss the Inojen with my Dr. and she refused even to discuss it. I think it was because they have their own preferred vendor.
    I have already talked to one of your specialists.

  • Emmanuel

    Is the oxygen concentrators better than the oxygen tanks

    • Ed Rodgers

      Hi. To answer the question, I think we need to qualify what better means. Both will deliver the needed oxygen to the person so in that regard there is not one that is better. Where the difference occurs is the mobility for a person. Unlike tanks, the oxygen concentrator uses the air to capture the oxygen. The machines are able to be brought on an airplane for use as well as more portable in transportation in cars than the green tanks. If you are using tanks, typically you need a delivery and pick up service which requires you to be home for those deliveries. From these brief aspects the use of oxygen concentrator is better for your ability to live a more mobile life without the weight and size of the oxygen tanks. Additionally, with tanks your are limited by the amount of oxygen in the tank whereas the concentrator can always have oxygen available. I hope this helps.

  • Les Drayton

    What is the comparison ( Bottled o2 against an o2 concentrator ) I am trying to say which is most cost affective buying o2 cylinders or e size o2 cylinder.
    I hope you can help

  • Olivia Agnes

    Do you deliver in Philippines or office ?

    • Ed Rodgers

      Hi Olivia, We unfortunately do not ship to the Philippines. If there is an address that is in the United State that would accept the delivery we can send it to that address. Hope this helps.

  • terry mclaughlin
    terry mclaughlin September 4, 2019 at 4:58 am

    What’s the difference between pulse flow and continuous flow? Thank you

    • Sanket Jain

      Pulse flow oxygen concentrators dispense oxygen in intermittent puffs depending on the breathing rate of the user. Whereas, continuous flow oxygen concentrators deliver oxygen in a steady flow, regardless of patient's breathing pattern.

  • Josh

    Hello, my younger brother recently was diagnosed with acute lung infection and has been on oxygen support for close to two months. We need to purchase the oxygen concentrator for him to use at home once he's discharged from the hospital. How do we get you to deliver to Nigeria and how much will it cost?

  • Nancy

    What is the difference between pressure based and timing based oxygen concentrators?

    • Sanket Jain

      I don't think I understood your question perfectly. However, I'll attempt to answer it as best as I can.
      Oxygen concentrators provide two kinds of airflow, namely, pulse dose and continuous flow. Pulse dose oxygen concentrators detect the patient's breath (by the negative pressure created in the tubing when the patient inhales) and deliver oxygen only when they inhale. They supply oxygen intermittently and not continuously. On the other hand, continuous flow oxygen concentrators supply oxygen steadily at the set levels. They supply oxygen continuously irrespective of the breathing rate. If they are set at 5l/min, then they'll deliver a total of five liters of oxygen in a minute. Learn more about it by clicking here.

  • Michael Moses, Sr.
    Michael Moses, Sr. May 11, 2020 at 9:35 am

    My doctor has said that getting oxygen from a portable pulse machine and straight from a tank is different. I believe that he is referring to if I need 3 lpm continuously that I would need a higher setting on pulse. I know that when I exercise or walk a lot that my numbers fall with the concentrator but stay better with a tank at continuous flow. As such, the Inogen tops out at 5lpm and it is not always good enough when doing more movement. Looks like I won't be able to use the Inogen for much longer?

    • Sanket Jain

      Yes, the pulse-flow oxygen concentrators are different from oxygen tanks, as they deliver oxygen when a breath is detected. It would be your doctor who will determine the pulse setting suitable for you. However, some portable oxygen concentrators offer both pulse-flow and continuous-flow oxygen. SeQual Eclipse 5 can go up to a setting of 6 on pulse flow and 3 LPM on continuous flow. Please, check with your equipment provider if they can process an exchange.


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