React Health G3 X Expert Review: The First Foam-Free Standard-Size CPAP in the U.S.

The React Health G3 X Auto-CPAP with Heated Humidifier is the first standard-size PAP machine sold in the U.S. built without polyurethane sound-abatement foam. It backs that clean build with an auto algorithm that tied for the best obstructive-event correction in independent bench testing, a 5-year warranty that more than doubles the category standard, and a price tag of $873 that undercuts the AirSense 11 by about $130.

We tested the G4600 model, which ships with the integrated heated humidifier, heated tubing, and a built-in 4G cellular modem. Whether you're shopping specifically for a foam-free CPAP machine, weighing the G3 X against the ResMed AirSense 11, or upgrading from the Luna G3, this review covers every angle: specs, algorithm performance, comfort, connectivity, pricing, and honest trade-offs.

Here's what stood out and where the G3 X falls short.

G3 X at a Glance: Specs and Score

Reviewed model: G4600, the G3 X APAP with integrated heated humidifier, heated tubing, and a built-in cellular modem. These specs come straight from React Health.

 

Our verdict: 4.5 out of 5

The device delivers strong therapy performance, with an auto algorithm that tied for the best obstructive-event correction rate among six devices in third-party bench testing. Comfort is well-addressed by an integrated heated humidifier, heated tubing, Reslex exhale relief, and a preheat option. While the built-in 4G modem and direct provider messaging offer robust connectivity, the patient app is less polished than ResMed’s myAir. Ultimately, the G3 X offers excellent value, combining a 5-year warranty with an $873 price point to provide the strongest cost-to-coverage ratio in the standard CPAP category.

Foam-Free Engineering: What It Means and Why It Matters

Most PAP machines use polyurethane foam to quiet their motors. That material is exactly what triggered the 2021 Philips recall. The FDA reports that the PE-PUR sound-abatement foam in roughly 15 million recalled devices can break down over time, releasing black foam particles or invisible chemicals that users could inhale or swallow. [4]

That recall changed how people shop for CPAP machines. The question "what's inside this device?" didn't exist for most buyers before 2021. Now it's one of the first things people ask. For a closer look at what happened and where things stand today, our Philips foam recall update covers the full timeline.

The G3 X addresses that concern directly. React Health says it is the first standard-size PAP available in the U.S. engineered without polyurethane sound-abatement foam. [2] Instead of foam, the device uses a honeycomb design to dampen motor noise. The result is still whisper-quiet: under 28 dB(A) at the standard 10 cmH2O test pressure, which puts it in the same range as the leading machines in its class. [1]

Smart A and Auto-Adjusting Pressure: How the G3 X Thinks

Auto-adjusting CPAP machines (also called APAP) monitor your breathing in real time and adjust pressure as needed throughout the night. Instead of holding one fixed number from bedtime to morning, the machine responds to each apnea or hypopnea as it happens. The American Academy of Sleep Medicine (AASM) strongly recommends starting PAP therapy either with home APAP or an in-lab titration for adults without major comorbidities. [5] A 2012 systematic review of 24 trials found that APAP was comparable to fixed CPAP for clinical outcomes, with patients using it for about 11 more minutes per night on average. [6]

The G3 X adds a second layer on top of the standard auto algorithm called Smart A. It reviews your last five effective therapy sessions (four or more hours of use with a controlled leak) and fine-tunes the auto pressure window to match what you actually needed. It uses your 50th- and 95th-percentile pressures to adjust both the minimum and maximum. Your pressure range follows your recent nights rather than staying at its initial setting. For a broader look at how auto-adjusting machines compare to fixed-pressure devices, our APAP vs. CPAP guide breaks down the differences.

The comfort features built around the algorithm include:

•        Reslex exhale relief (levels 1 to 3): Drops pressure slightly when you breathe out, so exhaling against the airflow feels more natural. Your care team sets the level.

•        Adjustable ramp (0 to 60 minutes, plus auto ramp): Starts at a lower pressure and gradually eases you up to your prescribed level while you fall asleep.

•        Auto On and Auto Off: The machine starts therapy after a few breaths into the mask and stops when you remove it. No buttons needed.

If you prefer a fixed pressure, the G3 X also runs in standard CPAP mode with a similar feature called SmartC, which adjusts the treatment pressure around your respiratory events in the same way. You can browse the full range of auto-adjusting CPAP machines or read our auto-CPAP machines guide to compare options.

Third-Party Bench Testing: How the G3 Algorithm Performed

React Health publishes bench data behind the G3 algorithm. The testing was conducted at Kernel Biomedical, an independent lab in France, in October 2024. A dynamic lung simulator fed six leading auto-CPAP machines the same scripted apneas, hypopneas, snoring episodes, and leak scenarios. The G3 platform device ranked at or near the top in the events that matter most. [3]

A note on transparency: this test was commissioned by BMC Medical (the G3 platform manufacturer) and prepared with React Health. The lab and protocol were independent, and the unit tested was the G3 platform device, which runs the same auto-algorithm family as the G3 X.

 

A few caveats worth noting: Bench tests use simulated breathing patterns rather than sleeping patients. The results are for the G3 platform device, and under heavy-leak conditions, the algorithm misreads some central events. No machine in the test aced every scenario.

Why does this matter to you? A machine that can distinguish between obstructive and central apnea events won't raise pressure when doing so could actually make things worse. That distinction is clinically important, and the G3 algorithm handled it well.

Comfort and Everyday Use: Humidifier, Heated Tubing, Noise

Day-to-day, the G3 X works like a modern bedside CPAP should. Warm, humidified air reaches your mask through heated tubing that reduces condensation buildup (rainout), and simple physical controls make adjustments straightforward even in the dark.

Humidification

The integrated humidifier holds 360 ml of water and offers six humidity settings (Off, Auto, and levels 1 through 5). There's also a preheat option that warms the water before bed and shuts itself off after 30 minutes. React Health recommends distilled water to prevent mineral buildup. The chamber is top-shelf dishwasher-safe for deep cleaning. [7]

Controls and navigation

You navigate the 3.5-inch LCD screen with a physical knob and home button. It's simple and functional, but if a touchscreen is high on your priority list, the AirSense 11 will feel more modern. The G3 X also includes a few quality-of-life extras: a bedside clock, customizable resupply reminders (30 to 365 days), and a Delay Off mode that runs the blower for about 15 minutes after therapy ends to air-dry the humidifier path.

Connections and compatibility

The G3 X uses a standard 22 mm conical outlet (ISO 5356-1) and works with the 19 mm standard or heated G3-series tubing. React Health recommends ISO-compliant CPAP masks, so your existing mask setup should connect without any issues. Consumables are shared across the G3 family, and you can find stock replacements in our React Health parts collection.

Maintenance

Replace the reusable air filter about every six months (clean it periodically before that). If you use the optional disposable ultra-fine filter, swap it out every two weeks. Clean the enclosure with hydrogen peroxide wipes and wash the water chamber with mild dish soap.

One important note: React Health warns that ozone-based CPAP cleaners can damage the G3 X and may void the 5-year warranty. [7]

Noise

The official spec is under 28 dB(A) at the standard 10 cmH2O test pressure. That's whisper-quiet territory. Like every CPAP machine, it will run louder at higher pressures, but at normal settings, most users and bed partners won't notice it.

Data and Connectivity: 4G, QR Code, SD Card, and the App Trade-Off

The G3 X sends your therapy data over a built-in 4G cellular modem to React Health's cloud platform. Your provider can review your nights remotely and even message you directly through the patient app. You can also pull a quick data snapshot with the QR code on the screen or export detailed data from the SD card.

This is a provider-first connectivity model. Data flows automatically to the care platform, so you don't have to do anything. Your care team can reach out to you through the app if they see something that needs attention. That direct communication channel is a feature React Health highlights as something the AirSense line doesn't currently offer. 1]

The honest trade-off: if you're switching from a ResMed machine, the app experience is different from myAir. ResMed's consumer app provides polished nightly scores and coaching tips that many users have come to expect. The React Health ecosystem is built more around clinical data sharing than consumer engagement. If a polished consumer app with nightly scores is your top priority, weigh that before switching ecosystems.

G3 X vs. Luna G3 vs. AirSense 11

The G3 X replaces the Luna G3 as React Health's flagship standard-size machine, and it goes head-to-head with the ResMed AirSense 11. Here's how they compare.

 Feature rows come from React Health's published comparison and verified specs. Prices are our current listings and can change.

For Luna G3 owners considering an upgrade

The three real differences are the foam-free build, the jump from a 2-year to a 5-year warranty, and Smart A custom pressure response. Everything else in the accessory ecosystem (water chamber, tubing, filters) carries over from the Luna G3, so you won't need to replace your existing supplies.

G3 X vs. AirSense 11

The G3 X wins on warranty length, price, and foam-free construction. The AirSense 11 wins on touchscreen polish and the myAir consumer app experience. If app-based nightly scores and a modern touchscreen interface matter most to you, the AirSense 11 is the better fit. If you'd rather have a longer warranty, a lower price, and peace of mind about foam, the G3 X is the stronger pick.

Budget angle

The Luna G3 Certified Pre-Owned at $299 remains the value pick for readers who want the G3 platform at the lowest possible cost. You'll give up the foam-free build, Smart A, and the longer warranty, but you'll get a reliable auto-CPAP at a fraction of the price.

For a broader comparison across all the top machines, our best CPAP machines review covers the full lineup.

Who the G3 X Is For (and Who Should Skip It)

No machine is right for everyone. Here's our straight answer.

The G3 X makes the most sense if you:

•        Want a machine with zero sound-abatement foam inside, full stop.

•        Value the longest warranty in the category (5 years vs. the usual 2).

•        Want strong auto-adjusting performance at about $130 less than the AirSense 11.

•        Already use a Luna G3 and want the upgrade without changing your accessory ecosystem.

•        Like the idea of your provider seeing your data and messaging you through the app.

Look elsewhere if you:

•        Want a touchscreen and the myAir-style consumer app experience above all.

•        Need a travel machine. At 3.75 lbs, the G3 X is a bedside unit. Check out our travel CPAP machines for portable options.

•        Are happy and compliant with your current machine. There's no clinical reason to switch if your therapy is working well.

Price, Warranty, and Prescription

The G3 X sells for $873 with the heated humidifier and heated tubing included. It's FSA/HSA-eligible and carries a 5-year manufacturer's warranty on the device, the longest in the standard CPAP category.

The fine print in the manual: accessories carry a 90-day warranty, and unauthorized repairs or damage caused by ozone-based cleaners can void coverage. [7] The G3 X is FAA-compliant (RTCA DO-160) and runs on universal 100-240 V power, so it works internationally. That said, at 3.75 lbs, it's designed for the nightstand, not the carry-on.

What's in the box (G4600):

•        G3 X Auto-CPAP with built-in humidifier

•        Humidifier chamber

•        6-foot heated tubing

•        2 reusable air filters (1 pre-installed)

•        Universal AC power adapter with cord

•        SD data card

•        Carrying case

•        User manual

All parts are natural rubber latex-free. Confirm the final list on the product page, as contents can vary.

Like every CPAP, federal law requires a valid prescription. If yours has expired, our RxExpress online prescription renewal can help. For a full walkthrough of the purchasing process, including how to buy a CPAP without a prescription, we've got you covered.

Ready to get started? Check the G3 X product page for the current price and box contents, or read our How to buy a CPAP machine guide for the full process from prescription to delivery.

FAQs

Is the React Health G3 X really foam-free?

Yes. The G3 X is engineered without polyurethane sound-abatement foam, the material behind the 2021 Philips recall, while maintaining whisper-quiet operation at standard test pressure.

What is the difference between the G3 X and the Luna G3?

Three things: the G3 X is foam-free, carries a 5-year warranty instead of 2, and adds Smart A custom pressure response. The G3-series accessories including the water chamber, tubing, and filters carry over between both models.

How loud is the G3 X?

Under 28 dB(A) at a standard 10 cmH2O pressure per the official spec, which is whisper-quiet territory. Expect more noise at high pressures, as with any machine.

Does the G3 X have an app like ResMed's myAir?

It has its own patient app connected through the built-in 4G modem, and your provider can message you directly through it. The experience differs from myAir, so app-first users should compare before switching.

Is the G3 X an auto-CPAP?

Yes. It runs both AutoCPAP and fixed CPAP modes. The Smart A feature fine-tunes the auto-pressure window based on your last 5 effective therapy sessions.

Do I need a prescription to buy the G3 X, and is it FSA/HSA eligible?

Yes to both. Federal law requires a valid prescription for any CPAP machine, and like other CPAP machines the G3 X is FSA and HSA eligible. An online prescription renewal service can help if your prescription has expired.

References

1. React Health. "G3 X APAP Device." Official product specifications.

2. React Health. "Clearly Foam Free."

3. React Health / BMC Medical. "G3 X Bench Test Study Summary." Bench testing by Kernel Biomedical, 2024.

4. U.S. Food and Drug Administration. "Recalled Philips Ventilators, BiPAP Machines, and CPAP Machines."

5. Patil SP, Ayappa IA, Caples SM, et al. "Treatment of Adult Obstructive Sleep Apnea With Positive Airway Pressure: An American Academy of Sleep Medicine Clinical Practice Guideline." Journal of Clinical Sleep Medicine, 2019.

6. Ip S, D'Ambrosio C, Patel K, et al. "Auto-titrating versus fixed continuous positive airway pressure for the treatment of obstructive sleep apnea: a systematic review with meta-analyses." Systematic Reviews, 2012.

7. React Health. "G3 X APAP User Manual," V1.0, January 2026.