Used Inogen One G5: Complete Buyer's Guide
Used Equipment Buyer's Guide | Main Clinic Supply
Used Inogen One G5: Complete Buyer's Guide
What the G5 is worth, what to inspect before you buy, and how to avoid the most common mistakes in the used POC market.
Fast Facts: Used Inogen One G5
- Device type: Pulse dose portable oxygen concentrator, 5 flow settings.
- Weight: 4.7 lbs with single battery; 5.8 lbs with double battery.
- Oxygen purity: 90% to 96% when sieve beds are healthy. Below 82% indicates degradation.
- Battery life: Up to 6 hours (single battery, setting 2); up to 13 hours (double battery, setting 2).
- Sound level: 38 dB, comparable to a quiet library.
- Used price range: $895 to $1,495 depending on condition, hours, and seller.
- Critical inspection item: Oxygen purity testing with an analyzer. Visual checks and power-on tests do not confirm therapeutic output.
- FAA compliant: Yes, with proper documentation and functional battery.
- Successor model: Inogen Rove 6 (6 flow settings, color touchscreen, Rate Responsive Therapy).
- Questions? Call Main Clinic Supply at 1-800-775-0942. Our oxygen specialists have 14+ years of hands-on G5 experience.
The Inogen One G5 spent several years as one of the most widely used portable oxygen concentrators on the market. It is compact, quiet, and capable of supporting active oxygen users across a wide range of daily activities. Now that the Rove 6 has taken its place as Inogen's current flagship, a significant number of G5 units have moved into the used market, and the pricing opportunity is real.
The risk is equally real. A used G5 that looks fine can be delivering far less than therapeutic oxygen if its internal sieve beds have degraded. After 14 years of servicing these devices at our Rochester, Minnesota lab, we have seen enough of this pattern that we want to put it plainly: buying a used portable oxygen concentrator without an oxygen purity test is guesswork. This guide will tell you everything you need to know to buy a used G5 with confidence, or to make an informed decision that a new device is the better path.
What the Inogen One G5 Is
The Inogen One G5 is a pulse dose portable oxygen concentrator cleared by the FDA as a Class II medical device. It extracts oxygen from ambient air, concentrates it, and delivers it in timed pulses synchronized with the user's inhalation. It does not store oxygen; it produces it continuously as long as it is powered.
The G5 delivers oxygen across five flow settings, with setting 1 delivering the smallest bolus and setting 5 the largest. Oxygen purity on a healthy unit falls between 90% and 96%, which meets the therapeutic threshold required by most physician prescriptions. The device is designed specifically for ambulatory use: its 4.7-pound weight and 38 dB sound level make it practical to wear on a shoulder strap or in a backpack throughout the day.
The G5 is not a continuous flow device. It does not deliver a steady stream of oxygen independent of breathing. This is an important clinical distinction, particularly for patients who require oxygen during sleep, during high-altitude exposure, or who have conditions that affect reliable breathing detection.
Full Specifications
| Specification | Inogen One G5 |
|---|---|
| Delivery type | Pulse dose only |
| Flow settings | 1, 2, 3, 4, 5 |
| Oxygen purity | 90% to 96% |
| Weight (single battery) | 4.7 lbs |
| Weight (double battery) | 5.8 lbs |
| Dimensions | 8.15" H x 3.26" W x 5.91" D |
| Sound level | 38 dB at setting 2 |
| Battery life (single, setting 2) | Up to 6 hours |
| Battery life (double, setting 2) | Up to 13 hours |
| AC power supply | Included; 100-240V universal input |
| DC power | Included; compatible with 12V vehicle outlet |
| FAA compliant | Yes |
| Operating temperature | 41°F to 104°F (5°C to 40°C) |
| Rated lifespan | Approximately 20,000 hours |
| Warranty (new) | 3 years parts and labor (does not transfer to secondary owners) |
Used G5 Pricing Guide
A new Inogen One G5 carries an MSRP near $2,695. Used units trade at a significant discount because the original three-year warranty does not transfer to secondary buyers. What you pay should reflect the device's age, total hours of use, battery condition, included accessories, and the credibility of the seller.
| Condition | Typical Price Range | What It Means |
|---|---|---|
| Certified pre-owned (inspected, tested, limited warranty) | $1,195 to $1,495 | Oxygen purity confirmed, battery assessed, accessories complete. Highest value for buyers who want confidence. |
| Good condition, low hours (under 8,000), complete accessories | $995 to $1,195 | Sold by knowledgeable seller or reseller. Ask for purity test results. |
| Average condition, moderate hours (8,000 to 14,000) | $795 to $995 | Higher risk of sieve bed wear. Budget for possible service if purity cannot be confirmed. |
| Unknown condition, private party, no documentation | $400 to $800 | Proceed only if you can test purity yourself or have it professionally evaluated before use. |
What to Inspect Before You Buy
Before money changes hands on any used G5, there are five things worth evaluating. Some you can check yourself; others require equipment or professional review.
1. Oxygen Purity
This is the single most important check. Oxygen purity should read between 90% and 96% on a calibrated analyzer. A reading below 87% warrants caution. Below 82% means the sieve beds have degraded to a point that the device is not reliably therapeutic. The G5 can look, sound, and operate normally while delivering insufficient oxygen. Do not skip this step.
2. Battery Capacity
Lithium batteries degrade with age and charge cycles. Ask for the battery's charge history if available, or run a full charge-to-discharge test to measure actual run time against the rated specification. A single battery that delivers only two to three hours on a device rated for six hours has lost significant capacity. Budget for a replacement battery ($175 to $295 new, depending on single or double) when pricing the total cost of ownership.
3. Error Code and Service History
Ask the seller if the device has displayed error codes or required service. The G5's internal diagnostics log error events. A history of recurring low-oxygen alerts or motor warnings is meaningful. A clean service history or documented repair from a qualified technician is a positive signal.
4. Physical Condition
Inspect the inlet filter, the nasal cannula port, and the housing for cracks or damage. Check that all buttons respond normally. Inspect the battery compartment for corrosion or evidence of moisture intrusion. Cosmetic wear is acceptable; functional damage is not.
5. Accessories Inventory
A complete G5 should include the AC power supply, DC automobile cable, carry bag, at least one battery, and the user manual. Missing items are purchasable but add to your true cost. Price them before committing.
The Sieve Bed Problem
Sieve beds are the core of any oxygen concentrator. They contain a molecular sieve material called zeolite that selectively adsorbs nitrogen from ambient air, concentrating the remaining oxygen. Over time and use, zeolite degrades. The device continues to produce some concentrated airflow, but the purity percentage drops below the therapeutic threshold.
According to Mark Luther, Certified Oxygen Specialist and CTO at Main Clinic Supply, sieve bed degradation is the most common finding when patients bring in used concentrators purchased elsewhere. "We regularly see units that the previous owner believed were working fine. The device turns on, it makes all the right sounds, but when we test purity it is reading 78 or 80 percent. That is not therapeutic oxygen. That is a patient unknowingly under-treating a serious respiratory condition."
Sieve bed replacement is a service option, but it has a cost. Budget approximately $250 to $400 for a professional sieve bed service, depending on the extent of degradation and parts required. When evaluating a used G5 at a lower price point, factor in this possibility explicitly.
Battery Condition and Costs
The G5 uses 8-cell (single) and 16-cell (double) lithium ion battery packs. Like all lithium batteries, they have a finite lifespan measured in charge cycles. A battery used daily for two years may retain 70% to 80% of its original capacity; one used heavily for three or more years may be significantly diminished.
| Battery Type | Rated Runtime (Setting 2) | Typical Replacement Cost | Weight |
|---|---|---|---|
| Single (8-cell) | Up to 6 hours | $175 to $225 | Included in 4.7 lb base weight |
| Double (16-cell) | Up to 13 hours | $245 to $295 | Adds approximately 1.1 lbs |
If the seller cannot confirm actual battery run time through a recent test, treat the battery as a likely replacement item and price accordingly. For travel users who depend on battery duration for flights or long trips, a degraded battery can be more than an inconvenience; it can affect compliance with airline battery documentation requirements.
G5 vs. Rove 6: How They Compare
The Inogen Rove 6 is the current model that succeeded the G5. If you are deciding between a used G5 and a new or certified Rove 6, understanding what changed is worth your time.
| Feature | Inogen One G5 | Inogen Rove 6 |
|---|---|---|
| Flow settings | 1 through 5 | 1 through 6 |
| Display | Button-based, monochrome LCD | Full-color touchscreen |
| Intelligent delivery | Standard pulse dose | Rate Responsive Therapy (RRT): adjusts automatically to breathing rate |
| Weight (single battery) | 4.7 lbs | 4.7 lbs |
| Sound level | 38 dB | 38 dB |
| FAA compliant | Yes | Yes |
| Warranty (new) | Not applicable (discontinued) | 3 years parts and labor |
| New retail price | N/A (discontinued) | Call for current pricing |
| Used price range | $895 to $1,495 | N/A (limited used inventory) |
The most meaningful advance in the Rove 6 over the G5 is Rate Responsive Therapy. Standard pulse dose delivery triggers based on a detected breath, but at higher activity levels, a user's breathing rate increases and the bolus timing can lag. RRT monitors breathing rate and adjusts delivery timing and bolus volume proactively. For active users, this matters. For a patient who uses their device primarily while seated or on light walks, the G5 remains clinically adequate at settings 1 through 5.
Who the G5 Is Right For
A used Inogen One G5 in verified good condition is a solid choice for a specific kind of oxygen user. It is not the right choice for everyone, and being clear about the distinction saves a great deal of frustration.
The used G5 makes sense if: your prescription is at setting 2 or 3 and unlikely to increase significantly, you are primarily ambulatory and need a lightweight travel device, your clinical team has confirmed pulse dose delivery is appropriate for your needs including during exercise, and you have either tested the unit yourself or purchased from a seller who has documented oxygen purity.
The used G5 may not be the right choice if: your flow requirement is at setting 4 or 5 and could increase, you need oxygen during sleep (pulse dose detection during sleep is unreliable for many patients), you plan to use the device extensively for air travel and battery longevity is critical, or you are purchasing from a private party without any documentation of device condition.
Patients who are oxygen-dependent and use their concentrator as their primary therapeutic device should weigh the cost savings against the risk carefully. A $400 gap between a used G5 and a certified alternative narrows quickly if a sieve bed service or battery replacement is required.
Service and Repair at Main Clinic Supply
Main Clinic Supply operates a dedicated service lab in Rochester, Minnesota. Our technicians have factory-trained experience on the G5 platform and have serviced thousands of units across its product life. If you have a G5 that needs evaluation, repair, or a pre-purchase inspection, we can help.
Our service capabilities on the G5 include oxygen purity testing and documentation, sieve bed evaluation and replacement, battery capacity testing, full diagnostic review and error code analysis, AC and DC power system testing, and parts replacement as needed. Turnaround time and service costs vary by the scope of work needed. Call us at 1-800-775-0942 to discuss what your device requires.
Frequently Asked Questions
What is the Inogen One G5?
The Inogen One G5 is a portable oxygen concentrator that delivers pulse dose oxygen across five flow settings (1 through 5). It weighs 4.7 pounds with the single battery, produces oxygen purity between 90% and 96%, operates at 38 dB, and is FAA-compliant for in-flight use. It is designed for active oxygen users who need a lightweight, travel-ready device.
How much does a used Inogen One G5 cost?
A used G5 in good working condition typically sells for $895 to $1,495 depending on age, hours of use, battery condition, and whether it comes with accessories. Units sold by a certified service provider with a documented inspection and warranty will cost more than private-party sales, but that premium reflects meaningfully lower risk. Call our team to discuss current used inventory and pricing at 1-800-775-0942.
What should I inspect before buying a used Inogen One G5?
The most critical item to verify is oxygen purity. Sieve bed degradation can cause a G5 to appear fully functional while delivering sub-therapeutic oxygen concentrations. A proper inspection requires an oxygen purity analyzer, not just a visual check or power-on test. You should also verify battery capacity, check for error code history, inspect the housing for damage, and confirm that all accessories are included.
What is the typical lifespan of an Inogen One G5?
The Inogen One G5 is rated for approximately 20,000 hours of use. A device used 16 hours per day will reach that threshold in roughly three to four years. For a used unit, total hours of use is one of the most important data points to request. Units under 8,000 hours with verified oxygen purity represent the strongest value in the used market.
Can I use a used Inogen One G5 on an airplane?
The Inogen One G5 meets FAA acceptance criteria for in-flight use on most commercial airlines, provided the battery is in good working condition and the device has its original documentation. Airlines require that the device meet FAA medical device criteria and that the user carry documentation from their physician. A used unit with a worn battery may not sustain required battery duration for longer flights, so battery capacity should be confirmed before travel.
What is the difference between the Inogen One G5 and the Inogen Rove 6?
The Inogen Rove 6 is the current-generation replacement for the G5. The Rove 6 offers six flow settings compared to the G5's five, features a full-color touchscreen versus the G5's button-based interface, and includes Rate Responsive Therapy (RRT), which automatically adjusts delivery in response to breathing rate changes. The G5 remains capable for settings 1 through 5, but the Rove 6 represents a meaningful advance in both usability and intelligent delivery for active users.
Does a used Inogen One G5 come with a warranty?
The original Inogen manufacturer warranty does not transfer to secondary owners. Warranty coverage depends entirely on the seller. Certified service providers may offer a limited service warranty on parts and labor. Private-party sales typically carry no warranty. Always confirm warranty terms in writing before completing a purchase.
What batteries are compatible with the Inogen One G5?
The G5 is compatible with the standard 8-cell single battery (approximately 4 to 6 hours at setting 2) and the 16-cell double battery (approximately 8 to 13 hours at setting 2). Battery life degrades with age and charge cycles. On a used unit, request documentation of battery capacity or ask for a battery replacement if the existing battery has significant wear. New replacement batteries cost $175 to $295 depending on the size.
Is the Inogen One G5 good for sleep?
The G5 is a pulse dose-only device, which means it delivers oxygen in response to detected inhalation. This delivery method is not universally appropriate for sleep use, as breathing patterns during sleep can become shallow or irregular in ways that may interfere with reliable pulse detection. Patients who require oxygen during sleep should consult their physician about whether pulse dose delivery meets their clinical needs, or whether a continuous flow device is more appropriate.
How do I know if a used Inogen One G5 has healthy sieve beds?
Sieve bed health can only be reliably confirmed with an oxygen purity analyzer. A reading of 90% or above is considered therapeutic. Readings below 82% indicate significant degradation. Visual inspection, sound, and normal operation are not reliable indicators. A device can generate normal-sounding pulses, show no error codes, and still deliver sub-therapeutic oxygen if the sieve beds have worn down. Main Clinic Supply provides professional purity testing at our Rochester, Minnesota service lab. Call 1-800-775-0942 to schedule an evaluation.
What accessories should come with a used Inogen One G5?
A complete used G5 package should include the AC power supply, DC automobile power cable, carry bag or backpack, one or more batteries, cannula, and the user manual. Missing accessories can be purchased separately but add to the true cost of the device. Always inventory accessories before completing a purchase and factor replacement costs into your budget.
Where can I get a used Inogen One G5 serviced?
Main Clinic Supply maintains a dedicated service lab in Rochester, Minnesota staffed by factory-trained technicians with deep experience on the G5 platform. Service includes oxygen purity testing, sieve bed evaluation, battery assessment, full diagnostic review, and parts replacement as needed. Call 1-800-775-0942 to discuss service options for your device.
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Disclaimer: This information is for educational purposes only and does not constitute medical advice. Portable oxygen concentrators require a prescription. Always consult your physician regarding your oxygen therapy needs. Specifications and pricing reflect information available at the time of publication and may be subject to change.