A History of Inogen Portable Oxygen Concentrators

A History of Inogen Portable Oxygen Concentrators

Oxygen is a colorless and odorless gas that is essential for maintaining life on earth. In humans, oxygen plays a crucial role in a process called cellular respiration where nutrients in the body are broken down and converted to usable energy. The atmosphere is around 21 percent oxygen which is enough for healthy lungs to maintain every cell in the body.


Unfortunately, not everyone has healthy lungs. Those suffering from respiratory diseases like chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF) have decreased lung function meaning the small amount of oxygen found in the atmosphere is not enough to keep them healthy. These people may experience symptoms like shortness of breath and chest pain. Long-term oxygen deficiency can even lead to organ damage and increase their risk of experiencing a heart attack.


Oxygen concentrators are one of the most popular methods of oxygen delivery because, as long as they have a source of power, they are able to provide an infinite supply of oxygen. This enables oxygen patients to have more freedom in their day-to-day life by allowing them to focus on what they’re doing rather than worrying about their oxygen supply. Since the early 2000s, Inogen has been the leading manufacturer of pulse flow portable oxygen concentrators with their “G” series of products.


A History of Inogen Inc.

Inogen Inc. was founded in 2001 with the goal of providing oxygen therapy patients with a better solution to their needs. As opposed to compressed oxygen tanks, commonly used throughout the 1900s, Inogen believed oxygen concentrators were the way of the future. Their mission was to make them much smaller, more lightweight, and easier to use than ever before. The way they sought to do this was by using pulse dose technology.

Inogen logo

Pulse dose is an oxygen delivery method that was invented to solve the issue of wasted oxygen. On a traditional continuous flow oxygen concentrator, oxygen is put out in a constant stream like a water fountain, indiscriminate of the user’s breathing rate. The downside of this is that there is a lot of wasted oxygen. On the other hand, however, pulse dose concentrators are designed to only distribute oxygen when the patient inhales. This enables oxygen manufacturers to make their portable breathing machines much smaller and lighter.


Aside from the Inogen at Home Oxygen Concentrator, Inogen has made use of pulse dose technology in every one of their oxygen devices. The most notable line of concentrators they offer is their “G” series. The “G” stands for generation, but don’t let the name fool you; older Inogen concentrators are still popular and viable even after the release of newer gen machines. Let’s take a look at each Inogen One unit to see how they compare.  


The Inogen One

The Inogen One Oxygen Concentrator was the first pulse flow oxygen machine released by Inogen, inc. At the time of its release, most oxygen concentrators were designed for in-home use only. In other words, they had no battery attached to the device. They would need to be plugged into a wall outlet in order to run. While the Inogen One oxygen concentrator only offered around 2 or 3 hours of battery life without needing to be charged, it was still much more than what people were used to.


Inogen One portable oxygen concentrator

In many ways, the original Inogen One concentrator was a lot like modern continuous flow oxygen concentrators. Because pulse dose technology was in its infancy, this oxygen machine weighed in at 9.8 pounds. This is very heavy when compared to modern pulse flow portable oxygen concentrators and as a result, it was typically transported by using a carrying cart rather than slung over the patient’s shoulder.


The Inogen One went up to a flow setting of 5 and had a unique feature called the “Satellite Conserver.” This was a device that was sold separately from the concentrator. It was attached to the oxygen tubing and allowed oxygen patients to increase the length of their tubing up to 100ft. In other words, you could have your oxygen machine charging in one room of the house while you’re doing something in another room. However, due to safety concerns, this feature was removed from future generation oxygen machines.


The Inogen One G2

The Inogen One G2 was largely built off the back of the original Inogen One. It had a very similar design with the carrying handle and control panel located on the top of the unit. In terms of specs, the Inogen One G2 improved in nearly every facet: the pulse flow settings were increased from 5 to 6; the battery life was increased from 3 hours to 8 hours; the sound level was reduced from 40 decibels (dBA) to 38 dBA, and the weight was reduced from 9.8 pounds to 7 pounds. While the Inogen One G2 was significantly lighter than the Inogen One, it was still primarily transported with a carrying cart.


Inogen One G2 portable oxygen concentrator

Another notable improvement of the Inogen One G2 was in terms of its enhanced usability. As opposed to the Inogen one which required you to pull down a hatch on the front of the unit in order to replace a battery, the G2 has batteries that detach directly from the bottom of the unit. The particle filter, which is responsible for removing impurities from the air, is also fully visible on the front of the concentrator. To clean it, simply pull on the tab, wash it off, and replace it once you’re done.


Inogen One G2 accessories

The Inogen One G3

The Inogen One G3 released in the fall of 2012 and to this day is still one of the most popular portable oxygen concentrators on the market. Weighing in at just 4.8 pounds and running up to 8 hours on one charge, the G3 is a great unit all around whether you simply want to get out for a few minutes each day or you want to travel around the world.


Inogen One G3 portable oxygen concentrator

Likely one of the first things you’ll notice about the Inogen One G3 is that it underwent a significant design change from the previous two Inogen models. Instead of having a handle on top of the unit and the filters on the front, the G3 has no handle on it and the particle filters were moved to either side. The front and the back of the unit now have the columns, the component that’s responsible for filtering nitrogen out of the air. Since the G3 is so much lighter than all previous iterations, there was no longer a need for the handle because it can be carried over the shoulder using the Inogen One G3 Carrying Case


Another great carrying option for the Inogen One G3 is the GO2 Carryalls. These bags were released quite a while after the release of the G3 but they offer G3 owners one more option for transporting their oxygen machine simply and comfortably. Unlike the normal carrying bag that comes with the G3, the GO2 Carryall offers a more fashionable and stylish option. The GO2 Carryall is designed like a purse and is made of 100% genuine leather. It can either be used as a handbag or slung over your shoulder. If you’re someone who’s self-conscious about carrying your portable oxygen concentrator, or you’re just looking for a bag that matches your outfit, the GO2 Carryall is a great option.


Inogen One G3 Carryalls


If the traditional carrying case or GO2 Carryalls don’t suit your needs, you’ll be happy to know there are two more options: the Inogen One G3 backpack and the Inogen One G3 Rolling Backpack. The regular G3 backpack is ideal for the traveler. If you enjoy taking trips around the country or even outside of the country, this backpack offers plenty of room for all your G3 accessories and even more room for additional personal belongings like your cell phone, tablet, laptop, car keys, and much more! The greatest part about all of this is that it holds your G3 securely and the control panel will be visible so you can make quick changes to your device’s settings. When it’s in the pouch, the G3 will be tucked close to you so that it doesn’t add any extra strain on your back as you go about your day.


The other carrying option, the G3 Rolling Backpack, is perfect if you want to pull your G3 behind you. However, the unique thing about this accessory is that it also has straps, so if you decide you want to pick it up and carry it on your shoulders, you can do that too! The ideal candidate for the G3 Rolling Backpack is someone who either issues with back or shoulder pain or someone who wants to have a versatile carrying option. Either way, you can’t go wrong with the G3 rolling backpack!


Inogen One G3 Rolling Backpack

All-in-all, the Inogen One G3 was one of the first oxygen machines to prove that it’s possible to have a great all-in-one portable oxygen device. Instead of sacrificing certain benefits, Inogen proved that it’s possible to make a POC that excels in every way including maximum oxygen output, lightweight design, battery duration, and ease-of-use. What’s more, Inogen took the time and effort to ensure every oxygen patient could customize their oxygen experience to their needs by releasing a slew of high-quality accessories.


The Inogen One G4

In many ways, the Inogen One G4 is an oddball when compared to the previous three portable oxygen concentrators Inogen had released. Rather than trying to improve on all aspects, Inogen wanted to make a portable oxygen concentrator that limited weight as much as possible. The result was one of the lightest portable oxygen concentrators ever produced!

Inogen One G4 portable oxygen concentrator

The Inogen One G4 weighs in at just 2.8 pounds! That’s just over a pound more than the AirSep Focus, the lightest portable oxygen concentrator on the market. Unfortunately, in order to achieve this feat, a number of other benefits were sacrificed with the G4. The flow settings are down from 5 with the G3 to 3 with the G4; battery life was reduced from 8 to 4.5 hours, and the sound level went from 39 dBA up to 40 dBA.  


With that being said, none of this makes the Inogen One G4 a “bad” portable oxygen concentrator. In fact, it’s pretty amazing how much power Inogen was able to pack into such a small and lightweight portable oxygen concentrator. Despite having a lower oxygen output and shorter-lasting battery life than the Inogen One G3, it will still be a great option for a lot of people out there.


Inogen One G4 next to apple

The ideal candidate for the Inogen One G4 is someone who has low oxygen flow needs but wants a reliable and lightweight unit. At only 7.2” H x 5.91” L x 2.68” W, the Inogen One G4 is extremely small so you won’t be bumping into anyone or anything if you’re walking in a crowded area. It’s even small enough to fit in a purse, although that’s not advised because your G4 needs to be able to take in air through its intake vent.


The majority of oxygen patients use a flow setting of 2, so for a lot of people, the G4 will serve them just fine. If you suffer from back or shoulder pain, the lightweight design of the G4 will ensure that you never feel encumbered and it will prevent that feeling of breathlessness if you’re out of the house for an extended period of time.


Inogen Connect app

One of the additional features that was added with the Inogen One G4 is the Inogen Connect. This is an application that can be downloaded on your smartphone or tablet  The app connects your phone to your G4 wirelessly using Bluetooth and provides you with up-to-date information about its battery status and column integrity. Another thing this app allows you to do is to check your device’s user manual no matter where you are in the world. This means you’ll never have to carry around a hard copy of your user manual because you’ll always have access to it on your phone.


The Inogen One G5

The Inogen one G5 was released in the summer of 2019 and it’s the latest oxygen concentrator manufactured by Inogen. The Inogen One G5 is one of the most advanced and sought-after portable oxygen concentrators on the market, and in many ways, it’s a continuation of what the Inogen One G3 set out to accomplish back in 2012.

Inogen One G5 portable oxygen concentrator

With flow settings 1 through 6 and a maximum oxygen output of 1,260 ml/min of oxygen, the G5 currently holds the record for the highest oxygen output of any pulse flow portable oxygen concentrator. This is a huge deal because it means many oxygen patients who previously used continuous flow oxygen concentrators can now switch over to the lighter and smaller pulse flow units.


If that wasn’t enough, you’ll be happy to know that the G5 also offers a better battery life than most oxygen concentrators on the market. The only pulse flow portable oxygen concentrator to surpass the G5 in terms of external battery life is the CAIRE Freestyle Comfort which can run up to 16 hours on one charge!

Woman with Inogen concentrator

The Inogen One G5 has a built-in technology called an Intelligent Delivery System. Typically, your pulse dose oxygen concentrator will deliver oxygen doses whenever you inhale. However, the Intelligent Delivery System accounts for many other factors such as how deep of a breath you take as well as changing breathing patterns. What this means is that you can use your oxygen concentrator 24/7 even when you sleep. All the while, your POC will provide you with your needed oxygen.

Inogen One G5 interface

The Inogen Connect also made a return with the Inogen One G5. It works in the exact same way as it did with the G4 and of course, if you’re not interested in the app, you don’t have to use it. However, it is very useful if you want to be able to check the status of your device without ever having to look at it.


Why Are Inogen Concentrators so Popular?

Now that you know a bit about each of these portable oxygen concentrators, you may be wondering, “what makes Inogen concentrators stand out?” While there are many great oxygen concentrator manufacturers out there, few are able to provide oxygen patients with the reliability that Inogen does. 


Inogen Inc. realized very early on that oxygen patients have goals, dreams, and aspirations, and outdated oxygen therapy devices like compressed oxygen tanks and liquid oxygen tanks were not providing them with the options they needed. Ever since their inception, Inogen has been laser-focused on making their oxygen concentrators more powerful, reliable, and easy to carry. Judging by the products they’ve put out, they’ve accomplished this with flying colors in a way that many other oxygen companies could not. 


What’s Next for Inogen Portable Oxygen Concentrators?

Another question you may be wondering is, “what’s the next major innovation coming for portable oxygen concentrators?” While it’s impossible to say where oxygen therapy technology will be in five or ten years from now, it’s possible to make an educated guess based off where they are now and the direction they’re headed.


It’s likely that oxygen manufacturers like Inogen will continue to focus on refining pulse dose technology. AirSep has already proven that it’s possible to make an oxygen concentrator under 2 pounds and Inogen has proven that pulse dose can provide adequate oxygen for the majority of patients, so at this point, it’s just a matter of combining the two. Another thing that will likely improve is battery life. The Inogen One G5 offers a long battery life, but on higher flow settings, that number is cut down significantly. We’ll likely see this improve in the coming years.


Last but certainly not least, we’re likely to see a lot more interconnectivity between oxygen concentrators and other devices you own like your laptop, tablet, or smartphone. The Inogen Connect is just one example of what this may look like. However, other companies have experimented with it using their CAIREView™ Telehealth Technology. CAIREView™ is a system built into every Freestyle Comfort POC that allows you to track your oxygen usage, send and receive information from your oxygen provider, and remotely troubleshoot your device. 



Inogen Inc. has a long history of success, primarily when it comes to manufacturing pulse dose portable oxygen concentrators. It’s estimated that about 4.5 million patients around the world rely on Inogen concentrators for their oxygen needs. A number that’s sure to grow as they develop new reliable and innovative oxygen concentrators. If you’d like to learn more about Inogen oxygen machines, stay tuned to our blogs where we cover all the latest information pertaining to oxygen devices. 

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