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Certified Pre-Owned Inogen One: G3 vs G4 vs G5 — Which Is Right for You?
Choosing between the Inogen One G3, G4, and G5 comes down to one simple question: how much oxygen do you need, and how much do you want to carry? All three are proven, genuine Inogen portable concentrators — the difference is in power, weight, and battery life. This guide breaks down which one fits your daily routine, your travel plans, and your budget, so you can buy with confidence.
In short: the Inogen One G3 is the most affordable, dependable all-day choice, with up to 5 pulse settings and strong battery life (up to ~10 hours with the extended 16-cell battery). The G4 is the lightest and smallest — ideal for low oxygen needs (settings 1–3) and ultra-light travel, though it has the shortest runtime (up to ~5 hours). The G5 is the most powerful and independent, with 6 pulse settings, the highest oxygen output, up to ~13 hours of runtime, and Bluetooth via the Inogen Connect app. All three are genuine Inogen units, FAA-approved for air travel, pulse-dose only (not continuous flow), and backed by a 1-year warranty by American Oxygen.
| Inogen One G3 | Inogen One G4 | Inogen One G5 | |
|---|---|---|---|
| Weight | ≈4.8 lb | ≈3.3 lb (lightest) | 4.7 lb |
| Pulse settings | 5 (1–5) | 3 (1–3) | 6 (1–6) |
| Max pulse output | up to 1,050 mL/min | up to 630 mL/min | up to 1,260 mL/min |
| Standard battery runtime | up to ~6.5 h (8-cell, setting 1) | up to ~2.7 h (4-cell, setting 1) | up to ~6.5 h (8-cell, setting 1) |
| Extended battery runtime | up to ~10 h (16-cell, setting 1) | up to ~5 h (8-cell, setting 1) | up to ~13 h (16-cell, setting 1) |
| Bluetooth (Inogen Connect) | No | No | Yes |
| FAA approved for air travel | Yes | Yes | Yes |
| Sound level | ≤39 dBA | ~40 dBA | 39 dBA |
| Best for | Best value for reliable, all-day use | Ultra-light travel & lower oxygen needs | Highest output, longest runtime & app connectivity |
Inogen One G3 — best value for reliable, everyday oxygen
If you want a dependable portable concentrator without paying new-unit prices, the G3 is the smart entry point. It offers five pulse settings (up to 1,050 mL/min), quiet operation (≤39 dBA), and up to ~10 hours of runtime on the 16-cell extended battery at the lowest setting. It’s a little heavier than the G4 and G5, but for many buyers the value and long battery life make it the easiest choice for day-to-day use at home and around town.
See the Inogen One G3 Certified Pre-Owned →
Inogen One G4 — the lightest, most travel-friendly option
At about 3.3 lb with the double battery, the G4 is the smallest and lightest Inogen One we carry — easy to wear on the shoulder all day and effortless to pack. It offers three pulse settings (up to 630 mL/min), so it’s best for people with lower oxygen needs. The trade-off is battery life: up to ~5 hours with the double battery. If maximum portability matters more to you than long runtime or high output, this is your model.
See the Inogen One G4 Certified Pre-Owned →
Inogen One G5 — the most powerful and independent
The G5 is the flagship: six pulse settings and the highest oxygen output of the three (up to 1,260 mL/min), yet it still weighs just 4.7 lb. Pair it with the 16-cell extended battery for up to ~13 hours of runtime, and use the built-in Bluetooth with the Inogen Connect app to check battery and settings right from your phone. If you have higher oxygen needs, want the longest independence, or simply want the newest technology, the G5 is the one.
See the Inogen One G5 Certified Pre-Owned →
Why buy Certified Pre-Owned from American Oxygen
Every Certified Pre-Owned Inogen One we sell is a genuine, FDA-cleared Inogen unit — fully inspected, deep-cleaned, and diagnostically tested to perform to original standards, with new critical components (like sieve beds and batteries) installed where needed. You get the same clinical pulse-dose performance as a new unit, at a much more accessible price. Each concentrator is FAA-approved for air travel and backed by a 1-year warranty by American Oxygen, with free shipping from our Miami facility. Our team helps patients and caregivers compare these models every day — we’ll help you match the right unit to your oxygen prescription, not just sell you the most expensive one.
Frequently asked questions
Which Inogen One is the lightest?
The Inogen One G4 is the lightest and smallest, at about 3.3 lb with the double battery. If carrying weight is your top priority, the G4 is the easiest to wear all day.
Which one lasts longest on a single charge?
The G5 reaches up to ~13 hours on the 16-cell extended battery at the lowest setting; the G3 reaches up to ~10 hours on its 16-cell battery; and the G4’s double battery lasts up to ~5 hours. Runtime drops as you raise the flow setting on any model.
Can I fly with these concentrators?
Yes. The Inogen One G3, G4, and G5 are all FAA-approved for air travel and can be used in the cabin on most commercial airlines. Always confirm your airline’s battery requirements before you fly — many ask for enough battery to cover 150% of your flight time.
What does Certified Pre-Owned mean?
It means the unit is a genuine Inogen One that has been fully inspected, cleaned, and tested to meet original performance standards, with new critical parts (such as sieve beds and batteries) installed where needed. Every Certified Pre-Owned unit includes a 1-year warranty by American Oxygen covering the concentrator and included accessories.
Which is best for higher oxygen needs or all-day use?
The G5 offers the most settings (1–6) and the highest output (up to 1,260 mL/min), followed by the G3 (up to 1,050 mL/min). For long days, pair either one with the extended battery and keep a spare charged. Always match your concentrator to your prescribed oxygen setting — ask your provider if you’re unsure.
Do these deliver continuous flow?
No. The G3, G4, and G5 are pulse-dose only — they deliver oxygen as you breathe in. If you’ve been prescribed continuous-flow oxygen, these models aren’t the right fit; call us and we’ll point you to a suitable option.
Not sure which one is right for you? Talk to a specialist.
Our Miami, FL team helps patients and caregivers choose the right portable oxygen concentrator every day — in English and Spanish. Call (786) 755-8063 and we’ll help you compare the G3, G4, and G5 against your oxygen needs and budget, or browse all Certified Pre-Owned portable oxygen concentrators →.