Product Review: Inogen One G2 & Inogen One G3

Inogen One G2 and G3 Portable Oxygen Concentrators
Inogen One G2 and G3 Portable Oxygen Concentrators

Related Article: Where to Buy an Inogen Portable Oxygen Concentrator

Inogen has been a leader in the portable oxygen concentrator industry, producing one of the first portable oxygen concentrators in 2004. Since the original Inogen One concentrator, Inogen has improved their design twice and now offers both the Inogen One G2 and Inogen One G3. I will review these two POCs together.

Primary Features

The Inogen One G2 and G3 are pulse only portable oxygen concentrators, using a minute volume delivery method. This means that they will provide a fixed amount of oxygen each minute regardless of your breathing rate. If you breathe faster, you get less oxygen per breath; if you breathe slower you get more oxygen per breath. The Inogen One G2 provides up to pulse setting 5, while the Inogen One G3 provides up to pulse setting 4.

Both models come standard with the Inogen One G2 or G3 concentrator in an attractive carry bag, AC and DC adapters for home and car, one (1) rechargeable battery in your choice of size. The Inogen One G2 also comes standard with a wheeled cart.

Inogen is the only company that offers two battery options – a small battery that keeps the weight down (7.5 pounds for the G2 and 5 pounds for the G3), or a large battery that lasts twice as long, but does increase the weight a bit (9 pounds for the G2 and 6.25 pounds for the G3). Most retailers will provide additional batteries at a discounted price when you add them to the purchase of your Inogen One.

Optional accessories include an external battery charger and backpack.

Both models are FAA approved for airline travel.

Inogen One G2 and G3 – What I like:
  • Dependable – Inogen is known for quality manufacturing, with fewer service issues than with most other POCs
  • Quiet motor – Inogen units have noticeably quieter motors than other POCs
  • Two battery size options – you decide which is most important, lighter weight or longer duration
  • Pulse flow settings of 1-2-3-4-5 for the G2 and 1-2-3-4 for the G3 (UPDATED 11/1/13: The Inogen One G2 now provides up to setting 6. The amount of oxygen per breath at 20 breaths/minute:
    • Setting 1 = 10.5 mL
      Setting 2 = 21 mL
      Setting 3 = 31.5 mL
      Setting 4 = 42 mL
      Setting 5 = 52.5 mL (G2 only)
      Setting 6 = 63 mL (G2 only)
  • Inogen One G3 is the smallest portable concentrator providing up to pulse setting 4
Inogen One G2 and G3 – What I wish were better:
  • Noisy purging sound on the G3 – Only the Inogen One G3 has this issue. The purging sound, which is the noise produced by the unit when it exhausts the non-oxygenated air, is rather loud. The unit purges about once every 15 seconds. Many people are not bothered a bit by the noise; others are quite distracted by it. The G3 is not a unit you would want to take to a quiet place like a fine dining restaurant or the theater.  I have heard that Inogen is working on this issue, but do not know when it will be resolved.
A special note about the Inogen One G3 and  the Sieve Columns

Inogen One G3 Sieve ColumnAn unusual feature of the Inogen One G3 is that it has sieve columns that can be replaced by the patient. The sieve is the part of the concentrator where the oxygen is concentrated. In all POCs, the sieve will wear out and need to be replaced. All other POCs, including the Inogen One G2, cover the sieve under the standard warranty for the unit (usually 3 years); therefore, the manufacturer will cover the replacement of the sieve within the warranty period, but charge upwards of $400 for replacement once the unit is out of warranty.

The Inogen One G3 sieve columns have only a one-year warranty, yet are expected to need replacing about every 24-30 months. Since this is out of the warranty period, yet prior to unit’s 3-year warranty, Inogen has designed them to be easily replaceable by the patient. The pair of columns is expected to be around $150 and would be available for purchase as an accessory item.

At first I viewed this as a design flaw. Why would Inogen knowingly produce sieve columns that would not last as long as on other models? However, I now see the advantages. Knowing that the sieve of all POCs will need to be replaced shortly after the unit is out of warranty, the cost of replacing the sieve columns on the G3 is fairly low when you consider the cost to replace a sieve on other models. And since you can replace the sieve columns yourself, you do not have the hassle of having to send your unit off to the manufacturer for service.

All-in-all, apart from a caution with regard to the purging sound of the G3, I would highly recommend both the Inogen One G2 and the Inogen One G3 for oxygen users who are looking for a small, lightweight unit that provides a pulse flow of oxygen.

Two companies that sell the Inogen One G2 and Inogen One G3 are OxiMedical and POC Medical.


    • says

      Unfortunately, knowing that your mom has COPD does not help me make a recommendation to you. What is more important is the amount of oxygen her doctor has prescribed and her mobility needs.

  1. Megan says

    This article is incorrect in one aspect. Both the G2 and G3 are constantly calculating your breathing patterns, and giving you the correct amount of oxygen per breath. It changes when your breathing patterns change, in order to dose you with the correct amount of oxygen based on your prescribed liter/minute setting. Also, if Medicare/your insurance is paying for your Inogen equipment, the sieve bed replacement is fully covered.

    • says

      Yes, the Inogen adjusts to your breathing rate and provides a minute volume delivery. Therefore, as I stated above, you will received less oxygen PER BREATH when you breath faster and more oxygen PER BREATH when you breath slower, so that you are always receiving the same amount of oxygen per minute. Thus, I do not think my information is incorrect. However, please forward me your source if you still disagree with the information I have provided.

      Thank you for the information about the sieve column. That is helpful for those who have insurance or Medicare coverage.

      • Vicky says

        I can not quite understand how or why you would get less O2 when you breath faster, wouldn’t that be when you need more… not when you are breathing normal… if I am having a problem breathing and am breathing faster I need more oxygen.. not less.

        • says

          I agree, that is generally when you would need more oxygen. However, the small units have limited capacity and are unable to provide a uniform amount of oxygen when the breath rate increases. The minute volume delivery system is something not widely known and people often are unable to use a small unit for this reason.

          Of course, the unit can be set to a higher flow setting if more oxygen is needed. That would require that you have a unit with a higher flow capacity than your resting needs. For instance, if you usually use setting 2, the Inogen One G3 could be increased to setting 4 when you become short of breath and would provide more oxygen. But if you usually use setting 4, then you would have nowhere to go with the settings. In this case, a larger unit, such as the Inogen One G2, which goes up to setting 6, would be best.

  2. Nancy Wilkinson says

    will there be a poc available soon or in the next year that is smaller than the resperonics simple go at 10 lbs I want to have option of wearing on my waist like a pager or at least weigh less. I find it hard to keep dragging the cart in and out of the car when shopping . I need to have only a 2 pulse dose but sometimes put it up to 3-4 when out and about . Continous would be soooo nice,

  3. Judi Wilson says

    I am fairly new as an oxygen user but here is what I have learned so far. Number one, my medicare complete would NOT pay towards my concentrator at all! But without the oxygen assistance, I would be kept from my activities. I show dogs. I discovered how needy I was at higher altitude when I spent a weekend in Flagstaff at dog shows. I had an ugly time and went to my wonderful pulmonologist when I got back to the valley. After a series of tests, he wrote orders for a concentrator for me. His office recomended the Inogen One G3. I started reading everything I could find and it looked good. I am a 70 yo woman weighing about 120 or less, so size and weight were very important and because I handle large dogs, I needed something flexible.

    I wanted to buy from a bricks and motar store if possible. Wow, did I luck out! I found OxiMedical and they have been wonderful. I have some disappointment with Inogen and everyone should be cautioned that they quite over-state the virtues of their product. They state “up to 4 hours” on battery …….. but I found that to be untrue under any normal use. At 2 level I was only able to get <3 hours. I guess technically "up to" covers that, but it is misleading and deceptive. Because the batteries are very expensive as is the independent charger, buying additional batteries and the charger are simply not possible after purchasing the unit with my own $$$ . So, in that respect, I am disappointed with the Inogen and believe they could be more forthcoming in their material (and perhaps more reasonable in their batteries and chargers). That disappointment is compensated for with the great service I have received from OxiMedical. They adapted the carrier case for me, helped me out with tubing (lesson learned regarding using the unit in a motel) and generally offered me all the assistance I could ask for. I could not be happier. I would send anyone needing concentrators of any kind large or portable to them in a heartbeat. Thank you

    • says

      Thank you, Judi, for your candid assessment of the Inogen One. The experience an oxygen user has with a particular model will depend greatly on their oxygen needs, financial abilities, and personal expectations. And the support you get from your dealer goes a long way, too! I’m glad you found a company that has been so helpful. Kudos to OxiMedical!

    • says

      When companies list their battery life on any product, they always list the maximum battery life on limited use. The four hour time on the battery would more than likely refer to use at setting 1. As you increase the settings the time would decrease. This is not misleading by Inogen. They are just telling you what is the “possible maximum battery use”. Consumers just need to be more aware.

  4. lizelle says

    Hi Alison,

    i’ve been reading all the information I can get my hands on – even medical journals!! not that I understand much of that, but nevertheless quite interesting….

    I need to find the best option available in POC (on an as needed basis – continuos flow, 5lpm – needed as a back up to a home system, long or multiple battery, car charger and very light weight ) which is available in South AFrica or could be sent there and still be covered by the warranty. I’m also not sure what a dealer would offer – Inogen’s video expect you to ;’say goodbuy to your current supplier and rely on the POC only’ – really! – Is there a POC which makes travelling between countries less laborious? The lungfoundation in Australia have been really great resource for much information and assistance, but RSA don’t have one. Although the World lung foundation cover RSA, can’t find more than medical Trials and TB info though. Converting the power to RSA standards would be a concern too. Any advice would be appreciated, thank you

    • says

      Unfortunately, there are not any POCs on the market that will provide 5 LPM continuous flow. The most a POC will produce on continuous flow is 3 LPM.

      The Inogen One G2 is a good unit if you can use a pulse flow. I wouldn’t recommend giving up a home oxygen concentrator and relying only on a POC. With all the bells and whistles they need to operate, there is much more that can go wrong with a POC, and a backup is always recommended. However, Inogen units are pretty reliable. U.S. retailers are not allowed to ship internationally. But Inogen does have partners in Africa; please visit their international listings at

  5. Ron Cochrane says


    Great blog and helpful. I have had the Inogen one G3 for around 3 months. Bought in the USA and shipped to Shenzhen China were I live.

    After 3 months normal use I now get a warning message “low Oxygen..see User manual” The User manual says “see your supplier”

    Have you heard of this problem before, and if so is it something I can do myself. ?



    • says

      With the Inogen One G3, if the display says O2 Service Soon, then the sieve columns need replacing, which you can do yourself. However, an error of Low Oxygen means that there is something else wrong with the unit and it would need manufacturer repair. I think units purchased in the U.S. need to be repaired in the U.S. I looked at Inogen’s international partners and I don’t see any in China –

  6. Dana Busenbark says

    I started looking for a POC on 10/3/13. I finally got in contact with about 3 weeks after that. Today I got my POC. I love it. I think it is quiet, and it is smaller than I thought it was going to be. Walked around the apartment and showed my next door neighbor. I’m tickled with it. They gave me an oximeter with a lanyard as well to go with the Inogen One G3. The G3 is lighter and smaller than I pictured it would be. I can’t wait to get started on using it when I’m running around doing what needs to be done.

  7. says

    Hi, I am writing for my 87 yr old father that is trying to determine what kind of oxygen to get. He is debating between a concentrator such as the Inogen one and portable oxygen in the canister. He has COPD, and unfortunately, he does not have a specific perscription from his doctor. His doctor is open to him using either type of machine. My father seems to like the idea of the inogen but is worried about the quality of the product. He is rather mobile and probably would rather have something lighter over something less noisy (but I’ll be sure to mention the noise issue with the G3 just in case). Do you think the Inogen would be a good option for him?

    • says

      As long as his oxygen needs do not exceed Setting 4 pulse then the Inogen One G3 would be a good option. The advantage of a portable concentrator over cylinders is they do not run out of oxygen. You do have to keep an eye on the battery level, but the Inogen can also be powered via AC power or DC power in the car. If he ever intends to fly, then a portable concentrator is a must. As for reliability, Inogen makes a good product, but I have found the Inogen One G2 to be more reliable than the G3.

  8. Carol Buynak says

    I currently have a Invcare Xpo2. It is about 2 years old and in repair. Apparently I dropped it and caused some internal problem. Since it is under warranty they are repairing it for under $25.00. But I am so interested in the Inogen G3. On XPO2 I use pulse level 3 with good results. A full charge doesn’t last more than an hour and 1/2, so I turn it down to level 2 when I am sitting. Is the noise level of the G3 comparable to the level of the XPO2? Also, on 8 cell battery life at 3, I’ve been told it would last 3 hours, on a 16 cell, weight would be 5.8 lbs, #3 would last 6 hours. Could this be true??

    • says

      The motor of the Inogen One G3 is quieter than the XPO2; however, it has a loud purging sound every 15 seconds. If you contact a dealer, they should be able and willing to let you hear it over the phone; it is quite noticeable. Yes, the 8-cell battery will last 3 hours and the 16-cell battery will last 6 hours. However, the total weight with the 16-cell battery is 6.25 pounds. (The weight of 5.8 pounds that you were told may have not included the carry bag.)

  9. Norman Crosby says

    I just received an Inogen One G3 POC that I had done serious research on. Yes, it does make a loud purging click every 15 seconds, but at 5.8 pounds and its small size, that can be over looked very easily for me. I have owned and/or rented two other brands of POC in the past. I own and still have a Respreonics Ever Go that was my first POC. Unfortunately it is pulse mode only and I had trouble sleep with it. I then was supplied with a Devibliss iGo by the Insurance company. Love this machine, but it was very heavy (25 pounds with two batteries and cart) to travel by airplane and automobile. But in my Motor Home I could use the iGO 24/7 as it is pulse and continues flow. I made a 11,000 mile road trip last year with it in tow. I used the iGO as my main POC, with Ox2 bottle’s as backup. Now with the new G3 I hope to be able to use it for all portable and stationary conditions and also I can sleep with it just fine so far. There are some very interesting conditions that all POC are limited by, temperature’s below 41 degrees is there limit for long durations. Here in Alaska that does pose a problem for long stays outside in the winter when I am taking photograph’s of the Northern Lights. To get around this problem I have kept the small portable/luggable bottles of Ox2 to use for outside when the temps are below 41 degrees. I really appreciate the small size and light weight of the G3. I will keep you posted of my experiences with the G3.

  10. Keith says

    I need some advice. I purchased an SeQual Eclipse model 1000 3 years ago along with 4 extra batteries. This is my backup oxygen for travel and overnight stays away from home. I use it at 1Lpm in pulse mode. Recently it began alarming and both indicator lights came on. The dealer I purchased it from tells me it is the sieve needs to be replace. The cost of the repair will be somewhere around $1000 and only has a 90 day guarantee. So basically repair doesn’t make sense.
    I am thinking of just replacing the unit with a Inogen G3 because of the size but I am concerned about the purging noise. Is there a way to mitigate the noise when I’m in a quiet place? Could I put my jacket over it or something like that or am I being overly concerned about the noise.
    My big question is this. Is there a market for used batteries? I have 5 perfectly good batteries for the SeQual and while I have no problem returning it to the dealer for disposal, I hate to see the batteries just be wasted. As I understand it the batteries are compatible with a couple of the later SeQual Eclipse models. Is this true and if so how do I go about making them available to someone who can use them?
    Thank you,

    • says

      The purging noise of the Inogen One G3 is distracting to some and hardly noticeable to others. Some people feel very self-conscious in quiet environments, while some have found that others may take notice at first of the noise but are quite forgiving once they realize it is providing life-giving oxygen. I don’t think you can muffle the noise very much. You can cover part of the unit, but you have to be careful to keep the air intake and outflow areas well-ventilated. If you would like to try the Inogen One G2, be sure to make a purchase from a company that give you a 7-10 day trial and lets you exchange it for another model. If you find the noise of the G3 bothersome, you will be pleasantly surprised at the quietness of the Inogen One G2. It is a bit larger, but still much smaller than the SeQual Eclipse you have been using.

      As for your batteries, you can sell them on eBay, or perhaps the dealer you choose for your Inogen purchase may be able to offer a small credit for them. Of course, they’ll want to test them first to see how well they perform.

  11. Sally says

    I have the Inogen G3 and I use it mainly for traveling, I was concerned on the sieve you were speaking of. Does it need replacing every year with continuous use or just every year?

    • says

      According to Inogen, the sieve beds (metal columns) have an expected life of 1 year. Actual life will depend on frequency of using the unit and the humidity of the air in which the unit is used. The unit will display a message that says “O2 Service Soon” when the sieve columns need to be replaced. These should be replaced within 30 days of the alarm.

  12. Joe whyte says

    I recently spoke to somone at inogen (forget his name) and I thought he said it was possible to get a free 30 day trial of the G3. Did I hear (or remember) correctly?
    If so, which dealers would provide that free trial?

    • says

      I am not aware of Inogen’s free trial, but you may have heard them correctly. That would probably be an offer you would only receive if you purchase directly from Inogen. I’d be surprised if any dealer can extend the same offer, although you can find dealers with a 14-day trial period (

  13. Destiny Densley says

    I’ve used the Inogen G3 for over a year now and I love it for it’s size and weight… I don’t have the strength to haul tanks and I HATED the constant calls and having to sit around all day waiting for Oxygen tank delivery. I’m not ready to give up on live and wait on some company that wants to charge me for air. I did alot of research on the Inogen G3, the batteries last a long time and when I’m in a vehicle I can run with the adapter for the cigarette lighter or if I’m in a Hotel or visiting… can just plug it into an AC source. I will get a beeping error that used to scare me saying I need servicing but in reality I had pinched the hose and all I needed to do was to make sure the hose was okay and turn the machine off and on… AOK. I don’t hear so well and all this noise I read about isn’t an issue… I do have a large floor concentrator at home and it is ten times as noisy as the G3. If you can afford the G3, I would recommend it.

  14. Sue C. says

    I just purchased the Inogen G2 Independence Freedom directly from Inogen, and thanks the terrific customer service by the sales rep that I’m dealing with, I will probably be a long-time loyal customer. but right now I have a few issues. I prefer the pulse method of delivery, as it does allow the battery to last longer. I actually tested the G2 on both A/C current and battery current. The problem I encountered was that the G2 quit delivery any detectable pulse of air after about 3 hours of continuous use, using both just the battery, and then just the A/C plugged into to house outlet (with battery still in place for re-charging). I noticed that the G2 was making some very quiet popping noises, seemingly coming from inside the concentrator. I also noticed that while the green light continued to light upon intake of breath, the amount of oxygen with each breath diminished substantially over time, and since I was feeling dizzy and getting blurred vision, I checked my oxygen with an oximeter, and it registered only 88%, with a lot of variation up to 92% after several deep breaths of just room air. At the time this was happening, there were NO warnings or errors being displayed on the user window. It only ever showed Battery % full when on the A/C, or Battery hours and minutes left when running strictly on the battery. My sales rep transferred me over to technical services, and also wrote up a service report. After over 25 minutes on hold, the tech that finally answered was abrupt, and verged on rudeness.

  15. says

    Regarding the purge noise cited for the Inogen One G3 model how does it compare in “loudness” compared to a Respironics EverFlo model? How does the loudness sound compared to an Inogen G2 model and the Respironics EverFlo model?

    • says

      The purge is about the same as the Respironics EverFlo, but louder when compared to the EverFlo Q model. The Inogen One G2 is very quiet, so the purge is much louder.

  16. Joan Wilson says

    I’m new to home oxygen, and appreciate this review. What is the difference between pulse and continuous delivery? My home concentrator and O2 tank valve are set at 4. How does this compare with the numbers on the G2 and G3?
    Thank you in advance

    • says

      Your home unit is a continuous flow machine, meaning the unit is always sending out oxygen even if you step away and are not using it. With a pulse flow delivery, you get a puff of oxygen every time you inhale. If your oxygen tank has a regulator on it, then it is providing a continuous flow just like your home unit. If it has a conserver on it, then it is providing a pulse flow delivery. The G3 has a maximum pulse flow of 4, so you would be using the highest level it provides. Therefore, I would recommend the Inogen One G2, which provides up to pulse setting 6.

  17. says

    I’ve had the Inogen One G3 for about nine months now and I love it. I’m at 2L/M, so it last about 3+ hours. It’s so much better then those Oxygen tanks I had to lug around. We went on a trip to the Outer Banks in NC last year and only took the small unit with us. It was great all I had to do was plug it into the cars receptacle and I could go for hours. When we stopped to eat or use the restroom, I’d just unplug it and go in to the service area, then when I got back into the car I just plug it in again. We only needed the G3 cause I could use the batteries, AC plug or in the car DC plug. (I Looove it.) I’m so glad the sales rep. explained everything to me and the service is great when I call and have a question or need products. Keep up the good work.

    • says

      The motor hum of the SimplyGo is a little louder than the Inogen One G3; however, the G3 has a louder purging sound that is noticeable because it is not steady, but rather, makes a sound every 15 seconds.

    • says

      Most people use the same pulse setting as their continuous setting. Sometimes an increased setting is necessary. A fingertip pulse oximeter is necessary to determine your blood oxygen level. You would need to use whatever pulse flow setting keeps your blood oxygen at a level recommended by your doctor. Your doctor is the one who would need to advise you on the flow setting since oxygen is prescribed by a doctor.

  18. Juls says

    Being in only my 30’s and living with quite a disabling lung disease, I have lived with and enjoyed the benefits and freedom of portable concentrators for the past 6 years. My current xpo2, although I have found it to provide me with freedom to get outside my house, the battery life and connector is horrendous (loses charge very quickly and battery connector repaired 3 times within 18 months). When you are dependent on oxygen, running out of charge unexpectedly due to battery failure is not only not acceptable but life threatening. I am looking to replace this machine with something more reliable, and like many other readers have investigated the Inogen one G3 which appears to fit the bill well. A few questions- (1) is the 3 yr warranty an international warranty (I live in Australia, but a friend travels to the usa regularly and can purchase the same machine for almost half the price) (2) can the car charger recharge the battery when plugged into the unit, or only run the machine (3) does the machine have a tendency to become hot and overheat (I have used a freestyle and had overheating issues) (4) how would you compare the Inogen one g3 to the Activox in terms of quality, noise, common faults and breath sensitivity (I use 2-3 lpm pulsed for my POC, and 3litres continuous for my home concentrator). I have very poor lung function and my breaths are quite shallow. Thankyou for a very informative thread.

    • says

      In response to your questions: (1) I am not certain about the warranty, but I think the unit would have to be returned to the U.S. for repair if it is purchases in the U.S. (You can contact Inogen directly about this question – (2) Yes, the DC adapter will recharge the battery in an automobile while running the machine. (3) I am not aware of overheating issue with the Inogen One G3. (4) The Inogen is noisier than the Activox due to the purging sound. With regard to quality and sensitivity, I would lean toward the Inogen.

  19. Brenda says

    I am thinking of throwing my respronics out of the door and getting a inogen one C3 I have issues with my back as well as breathing problems. The one I have now makes me feel like a prisoner I do not want to go any where with it. It is heavy to take in and out of the car, I have to lift it into shopping carts to shop. and then my breathing is raised and the battery does not last long enough to go shopping.. Can anyone tell me how long does it really go on the batteries?

    • says

      The Inogen One G3 would be about half the weight of your Respironics unit. The battery time depends on the flow setting. Using the 8-cell battery at setting 2, it would last about 3 1/2 to 4 hours. Using the 16-cell battery at setting 2, it would last 7 1/2 to 8 hours.

  20. Pat Triska says

    About 4 months ago I received an Inogen G2 and love the fact that I have more freedom to do things. I do have one problem and was wondering if anyone else has the problem. When I am driving in my car and going up hills my unit does not disperse oxygen. As soon as I get on flat ground it starts working again. I have tried rebooting the unit, running on the battery only, and many other ways to see what is making that happen. Does anyone else have that problem? The unit has been replaced 4 times and today the 5th unit is to be delivered. The customer service at Inogen is fantastic. Everyone is very helpful. I love the convenience of the system. My setting is at 5 so thought that was the problem but customer service says “no”. Being at 5 the batteries do not last long so I always have to carry an extra battery with me when I shop. I am wondering if there is something that I am doing wrong but I do know that I am not breathing through my mouth when this happens.

  21. Fred says

    Inogen prouds itself in being so customer friendly but it’s warranty only extends to the original buyer. If you purchase a unit from a deceased user- tough luck

  22. KriStie says

    I have an inogen g3 that has started making a loud vibrating noise…any idea what could be causing this?

  23. Steven Serdinsky says

    I received my Inogen equipment two days ago, put it together the next day, used it for the first time yesterday, went out using the portable unit, I did not feel loaded down, it was as if I had left something cumbersome behind. Inogen has replaced the system I had/have, have not yet returned it. For my sake I hope that I am not jumping the gun on my review.
    There are so many great thing about this system, can’t believe that I am so enthusiastic. The indoor unit is smaller, it is quiet, cannot even hear it. The cannula is superior to the one I was using, it is thicker, that is important, the two ‘things’ that I stick in my nose, they are thicker and soft, they will not put ‘nicks’ inside my nose, meaning that they will get dry as fast as the ones I was using, meaning that they will not harden as fast and narrow so quickly. Talk about an upgrade, example, went from Window 98 to 8.1, a huge difference. A big expected surprise, a oximeter, think that is the name of the unit that can tell you quickly what you oxygen and heart rate are, what a great thing to have, brand name, fingertip. I have been on oxygen since 2001, have emphysema and COPD, had LVRS.

  24. Doug Corey says

    The Inogen literature claims that their “Intelligent Delivery Technology” works well enough that it can be used during sleep (I had read in many places that only continuous flow should be used during sleep). I’m curious if it would work with a CPAP? I suspect that continuous flow is necessary for that. I have an OxLife Independence POC which has pulse setting up to 6 and continuous flow up to 3 lpm. I mainly use it for travel. At 19 pounds it is “portable”, but the 7 pound Inogen G2 is certainly appealing to replace the O2 tanks I lug around now. Any idea of G2 battery life at maximum flows. (Inogen’s literature is deliberately vague on this.)

    • says

      Some people are able to use an Inogen during sleep; however, regardless of its technology, it is a pulse flow only unit, meaning you must inhale through your nose to receive oxygen. Inogen units will NOT work with a CPAP because you cannot trigger the pulse by inhalation with the CPAP machine between you and the Inogen. A CPAP machine requires a continuous flow of oxygen. If you need only 2 LPM continuous, you may want to consider the Respironics SimplyGo, which provides up to 2 LPM continuous and pulse settings up to 6.

      The Inogen One G2 12-cell battery would last about 2 hours at the highest setting and the 24-cell battery would last about 4 hours at the highest setting.

  25. Kent Cantrell says

    I have been using a G2 for 3 years now without any issues at all. However after a recent conversation with Inogen representatives (after I finally got to talk to someone) I must say I will never ever buy their product again. If you need service on the unit after warranty you must send it to them, and for a mere $495.00 they will fix only the error that is occurring at the time. Oh and you have to pay for the shipping both ways!! Now if you would like to have them do a little more like fix the error, give the machine a check up and get a 1 year warranty addition, you can get this for a mere $950.00! But Wait! If you would like to pay them $1900.00 they will kind of overhaul your machine and give you a 3 year additional warranty. Boy this sounds like such a good deal!!!
    What a crock Inogen, why don’t you make your machine serviceable like all the other POC manufacturers do. Oh, I know why! Because you want to take advantage of people who are on oxygen and probably on some fixed income and insurance! You ought to be ashamed of yourselves!!!!!

    • Julie says

      *disclaimer I do work for Inogen but you are welcome to fact check me*: First, I’m sorry you’re frustrated with the cost of repairs, unanticipated charges are always frustrating. Please note that Inogen does offer a lifetime (for the purchaser’s lifetime) warranty on both the G2 and G3 units, it costs 1000.00 more but as you point out, post warranty repairs are more costly in the long run. Secondly, if you are using insurance (including Medicare) benefits to get either device none of these charges would apply to you, you will always get a replacement device because you are in a “rental” type agreement. The warranty limitations are only on actual purchases, not insurance or Medicare coverage. Thirdly, the industry Reasonable Useful Lifetime (RUL) of any durable medical equiptment (DME) is 5 years (incidentally Medicare also defines RUL as 5 years on DME). With a lifetime warranty you don’t have to deal with the concerns of outliving your unit.
      I read these blogs because I want to understand the concerns of supplemental oxygen users, NOT to defend my company or any other. I appreciate the insights of actual users and will always strive to make your lives easier, no matter if Inogen has the right products for you or not.

  26. Laura says

    Have you heard other complaints of getting an error message “4b” on the G3? I’ve had my unit a little over a year, and this is the second time I’ve gotten this message. The unit shuts down immediately. I bought mine through Oxymedical, which has great customer service, and they told me this is a software problem. They replaced the unit, so this is the second unit to quit with this message. Unfortunately, since I am flying today I cannot get a replacement. This is a major problem–I don’t bring a backup O2 source when I fly! (Fortunately I’m heading home where I do have another O2 source.) I hope Inogen has fixed this bug.

    • says

      I have heard of Error Message 4B, although it does not seem to be a widespread issue. Error 4B is indeed a software issue, but unfortunately, Inogen does not provide any more detail than that. When the unit is serviced, it is given a software upgrade and a full diagnostic check is performed (other repairs are completed as needed). Hopefully, the software upgrade will fix the problem and I think it is very rare to have a 4B error twice on the same unit.

  27. Kelly says

    I bought an Inogen g2 that goes up to 6 lpm. Yes, they have a 30 day trial and can return which I intend. It doesn’t put out near enough Oxygen, even at 6 lpm to let me be active. I have been using tanks with a POC and 4 lpm usually is plenty. The sales rep is great but when trying to find out if there is a problem with the unit or if it just won’t work for me it is not pleasant. So far I haven’t been able to talk to a tech person and the “respiratory therapist” the sales person got to take my call told me she couldn’t talk to me because I was a cash patient, not insurance. The small amount of Oxygen these units put out surprises me. I don’t think I am an extreme needs patient and other than flying or high altitude driving I think it is useless. I can get a smaller lighter unit that puts out 2 lpm for flying for a lot less money but what do I do when I get off the plane and need 4 to 6?(pulse) The Inogen claims 6 but doesn’t deliver as far as I can tell.

  28. says

    I am disappointed with battery performance. I have an inogen 3. At the time of purchase I also bought 2 8hour batteries and one 3 hour battery. I find the 8 hour battery only lasts less than 6 hours and the 3 hour battery barely makes it to 3. At the time of purchase and in materials I read about the machine, this performance level was not disclosed. In the interest of good customer relations, I would strongly suggest more accurate disclosure. The machine works well, but I give a big F for battery performance.

    • says

      Inogen advertises the 8 hour battery time when used on setting 2. Since you are only getting 6 hours, I would expect that you are using setting 3 or higher. Is this the case?

      Also POC batteries will have shorter run times on higher flow settings.

  29. Jim Stephens says

    My experience with this unit is less than good. I have had it for less than 2 years and it is now going back for the third time for Low O2. This is now the 3rd time in less than a year. I am told it is due to the humidity in Florida. There is also no apparent way to contact Inogen directly. Have to work through the company that sold it, who simply writes up anther RMA to return to Inogen for which I pay the shipping and then I also have to rent a unit is mine is in the repair cycle.

    • says

      Thank you for providing your experience. Are you referring to the Inogen One G2 or G3? (I think it would be helpful for my readers to know.) Based on the issues you are having, I am guessing it is the G3, which eliminated the sieve cooling fan and allows for increased issues in high humidity environments.

      As for getting repairs, your experience is common, which is why I recommend choosing a dealer that offers a free loaner. You will still have to pay for shipping, but at least you don’t have to pay for a rental unit.

      • Delores says

        Wondering WHY high humidity causes reading of Low 02? I am still deciding which POC to buy but am leaning toward the G3; lighter POCs are too restricted (e.g., Focus, 2LPM only). I live in HI and seldom go out on my own at over 80% humidity but in FL (where we’re moving in 18 months or so) and I won’t have so much choice about going out. This seems a bit odd, though, since it gets extremely humid in the Midwest as well, so why is FL apparently a problem?? The battery life makes the G3 seem like the only “battery” POC viable for me.

        • says

          The molecular sieve material in sieve columns absorbs moisture. Knowing that, the Inogen One G2 has a special feature where the compressed air passes through a drying tower.

          In order make the Inogen One G3 the size that it is, Inogen removed the drying system. Thus, the humid air is absorbed by the molecular sieve material and does not last as long. This is the reason the sieve columns are warrantied for only 1 year for the G3 as opposed to 3 years for the G2. The unit will still work and provide oxygen, but you will have to replace the sieve columns more often than if you were in a dryer climate.

  30. Yassine says

    Hi, we have a prescription for 5L per minute for the oncle, & we needed a confirmation that the inogen G3 is suitable, please recommend
    Thank you

    • says

      The Inogen One G3 is a pulse only unit that provides up to setting 4. It is NOT suitable for a prescription for 5 LPM. If pulse flow can be used, the Inogen One G2 may be suitable; however, a larger, more powerful unit, such as the SeQual eQuinox or Eclipse 5, may be the most beneficial.

  31. brad williamson says

    I am researching these units for an uncle with COPD. He’s very interested in portable units. I was attracted to inogen after seeing a television advertisement for 30 day “risk free” trial. I’m as fair minded as any, and willing to balance any/all aspects of a company. Upon reading here that a customer could discover no way to “contact inogen directly” a primal alarm went off for me. Fifteen years into shopping via internet, any company that places such firewalls between itself and it’s end users is an instant non-starter for me. I’ve only recently seen this from suspicious websites of less than one month’s provenance or “wild west” Chinese vendors that offer extraordinary prices with accompanying high risk to the consumer.

    Inogen? No way. If it smells like a rat…….

    • says

      Inogen is by no means a new company, nor is it like a high-risk Chinese vendor. The previous commentor who said he was unable to contact Inogen directly was referring to needed repair work. Inogen has a phone number boldly displayed on their website; however, they require that service be arranged through the dealer from which the unit was purchased. All oxygen concentrator manufacturers have the same policy. You can liken it to automakers; if you have a problem with your car, you don’t call GM or Ford directly–you take the car to the dealer for repair.

  32. Melinda Pierce says

    My husband has had a total laryngectomy and breathes through a stoma in his neck. He requires between 1 to 1.5 lpm continuous flow. We did use a Inogen POC for a 3 week trip to Phoenix Arizona. Don’t remember which one as it was provided by his oxygen provider. It had a maximum pulse flow of 5 which seemed to work for him even while sleeping. We enjoyed the freedom of a POC but are concerned about the pulse flow versus the continuous flow. I have been told by two providers that their POCs are not FDA approved for “neck breathers”. Do you know if there are any of them that are approved? Also, do you know if there are continuous flow POC’s that we might consider for use in traveling?

    • says

      The official FDA-approved Indications for Use for the Inogen One concentrator is as follows: The Inogen One Oxygen Concentrator is used on a prescriptive basis by patients requiring supplemental oxygen. It supplies a high concentration of oxygen and is used with a nasal cannula to channel oxygen from the concentrator to the patient. The Inogen One Oxygen Concentrator may be used in a home, institution, vehicles and various mobile environments.

      Alternate units that provide continuous flow options would be the Respironics SimplyGo and the SeQual Eclipse or SeQual eQuinox. These units appear to have no restrictions for nasal cannula. For instance, the SimplyGo Indications for Use states: The Respironics SimnplyGo Portable Oxygen Concentrator is for prescription use by patients requiring high concentrations of oxygen on a supplemental basis. It is small, portable and is capable of continuous use in the home, institutional, and travel /mobile environments.

  33. Kerry says

    Is there anywhere to switch your Inogen one G3 over from battery to power source? I used mine on power source on a flight, the alarm kept going off stating error, service required. I am disappointed as the POC had only been used previously for 16 flying hours. I am visiting USA, my machine is still under warranty, I have had no luck liaising via my agent in Australia for a complete service prior to my return trip to Australia November 12 /14. I can have it repaired free of charge on my return home, that doesn’t help my dilemma for my flight home

    • says

      The Inogen G3 will automatically use the AC or DC power when they are being used, and will automatically use the battery when no other power source is available. The error you received may have nothing to do with the power being used. I recommend you contact the manufacturer directly at

  34. says

    Can the G3 be placed inside of a tote when traveling or or does it need to be fully exposed to function properly?
    Also, what is the maximum length of tubing fot the G3?
    Thank you

  35. Denny Stiers says

    I’ve got a G3 that I’d like to service myself because it was given to me by a gentleman whose wife passed away.
    I went to service it only to find it had screws holding in the canisters and a filter were quite exotic, and I had no screwdriver that matched them. We exist on Social Security and, Medicare will not cover the cost of repair to the unit. Who would I contact purchase the canisters filters and tools. Can you assist me in this matter. Looking forward to your response.
    Thank you for your time.
    Sincerely Dennis Stiers

    • says

      The canisters you are referring to are called sieve columns. These only need to be replaced when the unit alarms “O2 Service Soon” and can be purchased from any authorized Inogen dealer. The star-shaped screws give access to the lifetime compressor filter. This filter is not meant to be replaced, hence the name “lifetime” and can only be replaced by the manufacturer. Inogen does not sell this part to it’s dealers. If you need more service assistance, I recommend you contact, an authorized dealer that has great service reviews.

  36. Denny Stiers says

    Yes the O2 sensors on service soon, our problem is we can’t afford the $400.00 to 1300.00 to have it serviced by the dealer, and since the sieve columns are held in place by a star shaped screw, I need the driver bit, is it something I can buy at any hardware store or do I have to go to the dealer to get it if I can get it at all. We most certainly will have to afford the $150.00 for the columns, what I can’t pay is that exorbitant amount to have them popped out and replaced by the dealer.
    Thanks for listening.
    Denny Stiers

    • says

      You do not need any special tools to remove the sieve columns. There is a latch next to each column that will release the lock and the columns slide right out. You can see this on page 34 of the manual. If you do not have a manual you can view it online.

  37. mk says

    Dear Mr. Stiers,

    Iam responding to your message concerning replacing the sieve columns on the InogenOne G3 yourself. It is something I recently had to do and was a lot simpler than it looked in the diagram pictured in both the portable unit’s user manual or the directions enclosed with the new sieve columns.

    I was able to find pair of new sieve columns for purchase online for around $149.00 at Direct Home Medical. They also sell the inflow filters, which do need to be washed weekly by soaking in a solution of mild soap and then rinsed and dried throughly before being reinstalled. These filters cost only around $29.00, and Direct Home Medical is one of the few places where I have found them. I do recommend that you purchase a pair of these filters in addition to the new sieve columns because not only will you receive free shipping (the minimum purchase for free shipping is $99.00), but also it will mean the you will not have to stop using the portable unit while you wait for the freshly washed intake filters dry completely.

    Please do take some time to verify the information which I have provided in this message. Unfortunately, I do not have my purchaser’s receipt in front of me for reference and it has been some months since I purchased the sieve columns.

    In any case, I do wish you the best of luck with your new portable unit and I hope everything works out well for you, Mr. Stiers.

  38. Roberta Secrist says

    I have an Inogen One G2 that has not been used in several years. My husband passed away. I now want to give it to someone who needs such a device. I tried to charge each of the 2 batteries that I have and they would not charge. I contacted Inogen and they were frankly not very helpful saying that I would need to purchase some sort of a warranty contract and send it to them for service and said they were not able to give me the name of any other service location.

    I just want to be able to have someone local look at it and let me know if it’s only the battery that needs replaced or if there is a bigger problem. I want to be honest about what I am giving to my friend. I certainly do not want to create any unnecessary hassles for her, nor any unnecessary expenses. Do you know of any local service sites near the Cleveland, Ohio area where I could get a quote on what is needed?

    Thanks for your help.

    • says

      Unfortunately, Inogen does not have repair centers around the country; they handle all repairs at their facilities. However, for the purposes of testing your batteries and the oxygen purity of your machine, I have heard that has been helpful to people in need. You would have to ship your equipment to them, but I think you would get honest feedback.

  39. Jack says

    Re; The Battery’s for the G3.. We all know batteries degrade as they are recharged. The problem is knowing the (real) time left before you board a plane for a long trip. They will show fully charged but may last close to 1/2 the time. Is they a way to get an acuarate time left? Also, i was considering purchasing 2 spares. If i left them uncharged,new in the box, what would be the shelf life? Ive been told that if i buy spare columns, and if not used that they would go bad in about 3 months. Is that true? If the company shipped me 2 columns which are vacummed packed, would they last if i put them in a safe with a humidity dryer? Lots of questions, but you sound like the source for the correct answers.
    Thank You

    • says

      There is no way to know the real time left in a battery apart from using it and testing it personally. So if the 8-hour battery is lasting only 7 hours for you, then you have to track your available time left. Since lithium ion batteries degrade whether used or not, I would not recommend purchasing batteries only to have them sit on a shelf. You are better off using all your batteries in rotation. Or if you only need additional battery time for travel, you may want to consider renting batteries for a trip. Then you get fresh batteries without the expense and maintenance. I have heard that will rent batteries.

      With regard to the sieve columns, my understanding is that as long as they are in the original vacuumed packaging and kept at room temperature, they will last indefinitely. For further confirmation, you may want to contact Inogen directly.

      • Jack says

        Thank you Allison for the response. The issue with the batteries is figuring out the amt. of time and what is required for a long flight. When charging the batteries,they will say fully charged. But that will not mean an 8 hr. battery has 8 hours with of time.. It can get really tricky. And the airlines want you to have 150% of what is needed for your flight inc. stop overs etc.. Trick math,huh? Also, if you push your button and the Inogens electronics don’t function, then what would one do for a back up? Boy scout motto, be prepared. But how. Any suggestions..

        • says

          To calculate the number of batteries needed for a flight first determine the length of the flight (including layovers if they are too short to recharge batteries) and multiply by 150% or 1.5. For instance a 4 hour flight would require 6 hours of battery time, and a 6 hour flight would require 9 hours of battery time.

          Once you know the total battery time needed, then determine how long the batteries will last FOR YOU. For instance the Inogen large battery (24-cell for the G2 model or 16-cell for the G3 model) may last only 6 hours when you are using it. In that case, your would have just enough battery time for a 4 hour flight, but a spare would probably give you some peace of mind and may even be required by the airline. For a 6 hour flight you would definitely need a second battery.

          If your unit failed during the flight, the airline can, should, and most likely would, provide you with emergency oxygen.

  40. Kyra Lawrence says

    I am very new to the medical oxygen life but quickly see that a POC is necessary unless I want to be a prisoner in my home. I have a large a/c concentrator for home and 2 tanks for “emergency” use that last 2.5 hours that are replace only once a month. Just going to the doctors office will use the tank up..
    Are POCs covered by Medicare & supplemental insurance? I am interested in the Inogen One G3 or G2 but have no idea which would be the better choice.
    I have a 18 hour train trip planed very soon. I also have a trip to Italy in June. With connections Flight will be 12.5 hours. Can I use an electrical converter to charge batteries while in Italy? Also how long does it take to recharge a battery?

    • says

      If your doctor has prescribed oxygen 24 hours/day, your homecare company should be providing you with home oxygen and portable oxygen. Your portable oxygen should not be “emergency” only use, rather it should be sufficient for you to have an active life. I recommend contacting your homecare company about getting more oxygen cylinders, or a homefill system so you can fill them yourself.

      Medicare will not pay more money for more or better equipment. They pay the same amount for a POC as they would for tanks. Thus the homecare companies usually cannot afford to give you a POC for your Medicare benefit. Most people have to purchase their own POC.

      The Inogen One G2 and G3 are both good units, with the G2 being larger and providing up to setting 6 pulse, while the G3 is smaller and provides up to setting 4 pulse. Your oxygen and portability needs will dictate which is best for your.

      Since airlines require 150% of flight time in battery power, you will need 19 hours of battery time. With the Inogen units, this could be fulfilled with two large and one small battery, or three large batteries. If you travel frequently it would be best to buy the three batteries; however, if you do not plan to travel after your trip to Italy then you may want to purchase one or two batteries and rent the extra batteries for your trip.

      All POCs work on 220 power in Europe so you do not need a converter; you only need a prong adapter to allow the plug to fit into the outlets in Italy. The batteries take 4-8 hours to recharge.

  41. George E. Kuss says

    I have the InogenOne G2 and would recommend buying the back pack. It’s a lot easier to tote around. How long is the warranty on the smaller battery. I received one that will not hold a charge. I have two other smaller batteries which holds a great charge. Recently I flew from Spokane to Germany non-stop and only had to use one of the large batteries over the entire flight of 11 hours on setting one. I was surprised.
    Thanks, George

  42. Johan says

    I live in the USA and want to buy a G2 or G3 for my dad who lives in a remote area in South Africa. Are there any spare/replacement parts that would be recommended to buy upfront ? I doubt that there are any service / repair facilities anywhere near where my dad lives.

    • says

      I would recommend purchasing additional particle filters; there are 2 on each unit and they are sold in a pair of two. The G3 unit will also require sieve column replacement every 18 to 24 months. However, the unit will give a 30-day warning when these need to be replaced.

  43. cindy says

    Hi Allison! Just curious to know if you can sleep with the G3, I know it is mainly for when awake, but if I brought it to travel with could I use it to sleep at night as well?
    Thank you!

    • says

      The Inogen One G3 provides a pulse flow only. If you use a CPAP or Bi-PAP machine with oxygen, the G3 is not compatible and cannot be used. If you are using only oxygen then it would depend on how well you breathe through your nose while sleeping. Many people breathe very shallow or through their mouth while sleeping and do not trigger the pulse. It is best to be advised by your doctor, who may perform a sleep study to see how much oxygen you receive while sleeping.

    • says

      Thank you for your interest; however, my blog is not open to guest posts at this time. I will certainly keep you in mind should I decide to accept guest posts in the future.

  44. Harry says

    Hi, we got the O2 Service Soon message after having the Inogen One G3 for only 4 months. We use it for travel and some trips around town. We haven’t been using it a lot since we were trying to avoid having to replace the columns earlier than the 18 months to 2 years that the manual says the columns should last (we have other oxygen service at home). When I talked with the store where we purchased the unit, after consultation with their service person, I was told that unless the G3 is used regularly, like at least once a week, that the columns will require replacement earlier than the manual indicates. We live in Colorado so humidity shouldn’t be a factor. I couldn’t find anything in the manual that indicated that non-use would shorten the column life. Is this real, or did I get a unit that had columns that were almost worn out anyway? Any idea about that? Thanks.

    • says

      A portable oxygen concentrator should be used at least several hours each month. It is like a car – you don’t leave it sitting in the garage without being turned on. The sieve material will settle if the unit is not used regularly – weekly is optimal. That being said, the sieve columns should not fail after only 4 months. Fortunately, they are under warranty for 1 year, so your supplier can submit a warranty request to have them replaced at no cost to you.

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