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product image of the 3B Luna G3 CPAP Machine

Ideal For:

  1. People who feel comfortable with standard CPAP therapy
  2. Those who are prone to congestion during CPAP
  3. CPAP users who prefer beginning their therapy at low pressure and gradually increasing to prescribed levels


  1. The pressure levels do not automatically adjust, and should only be recalibrated by a licensed physician
  2. The Luna G3 is on the larger side, so it may be too bulky for practical travel
  3. You can use the machine with North American outlets, but will need an adapter to power your device overseas

Sleep Foundation Special Offer

Use this link for the most current React Health discount

React Health — formerly known as 3B Medical Inc. — offers an extensive selection of products for people with sleep apnea. The Luna G3 CPAP Machine is one of the brand’s most popular devices. As a standard CPAP machine, the device delivers air at a fixed pressure level based on your prescription.

The Luna G3 product line also includes a bilevel positive airway pressure (BiPAP) machine with different pressure levels for inhalation and exhalation, and an automatic positive airway pressure (APAP) machine that automatically adjusts pressure levels based on breathing patterns.

The Luna G3 CPAP Machine includes a built-in humidifier that can be preheated prior to use, as well as heated tubing. These features are intended to make continuous positive airway pressure therapy more comfortable and minimize congestion. You can also use the ramp setting to ease into your therapy by gradually increasing pressure. The Luna G3 is relatively affordable compared with competing devices.

We’ll take a closer look at the 3B Luna G3 CPAP Machine, including technical specs, device features, and tips for first-time users.

3B Luna G3 CPAP Machine Review Breakdown

Continuous positive airway pressure (CPAP) therapy is often the first treatment prescribed for people with obstructive sleep apnea (OSA). This type of positive airway pressure (PAP) therapy involves a machine that draws in outside air and pressurizes it to a certain level based on your prescription. This air is then delivered through connective tubing into your CPAP mask, where it enters your airway and allows you to breathe more freely.

CPAP pressure is measured in centimeters of water pressure (cm H2O). The Luna G3 can be set between 4 and 20 cm H2O, in 0.5 cm H2O increments.

One of the Luna G3’s most prominent components is a built-in humidifier that allows you to preheat the water in the chamber. The integrated tubing can also be heated. Heating the water helps prevent condensation from forming in your hose and mask.

Another useful feature is the ramp mode, which lets you begin therapy at a low pressure setting and gradually build to your prescribed level. Some CPAP users appreciate this mode because starting at their prescribed level can be jarring and uncomfortable.

What’s Included

The Luna G3 CPAP Machine consists of several individual components, each of which helps promote effective and comfortable CPAP therapy. Your purchase includes a CPAP device with a built-in humidifier, heated tubing, and other standard accessories. CPAP masks are sold separately, and also require a doctor’s prescription.

PAP TypeComponents
  • CPAP machine with built-in humidifier

  • Heated connective tubing

  • Filter
  • Power supply and cable
  • Product Features

    The Luna G3 lacks the bells and whistles of many competing CPAP machines on the market, but the device is still equipped with a handful of features to alleviate OSA symptoms and help you sleep comfortably while receiving CPAP therapy.

    Features:Ramp setting: The Luna G3’s ramp feature allows you to begin therapy at a low air pressure setting and gradually build to your prescribed pressure level. You can customize the ramp to last up to 60 minutes.
    Preheat function: The preheat function allows you to warm up the water in the humidifier’s chamber before your CPAP therapy begins. This can help with initial comfort.
    Humidity and temperature controls: The device includes five heat settings to warm the humidified air before it’s delivered to the tubing. The tubing can also be heated to prevent condensation in the hose and mask.
    LCD interface: The machine’s digital interface allows you to view machine settings and your sleep data. You’ll also receive reminders for replacing the air filter, connective hose, and face mask. The device has a knob that’s used to adjust settings.

    Sizing and Pricing

    While by no means cumbersome or bulky, the Luna G3 CPAP Machine is slightly larger and heavier than many CPAP machines sold today. The device measures about 10.4 inches across and has a depth of approximately 5.7 inches, so it will fit on most nightstands.

    Size Comparison:

    • Travel: The Luna G3 CPAP Machine is wider, longer, taller, and heavier than most CPAP devices designed for travel. That said, the machine is still relatively compact and shouldn’t add too much weight to your luggage.
    • Standard: The Luna G3’s size is on par with other CPAP machines featuring built-in humidifiers, which significantly add to a device’s surface area and weight. Most nightstands should provide adequate space for the machine.

    3B Medical Luna G3 CPAP

    10.4″ x 5.7″ x 4.5″3.75 lbs.$998

    Device Performance

    • Noise Level: The Luna G3 CPAP Machine produces around 26 decibels of sound when the pressure is set at 10 cm H2O. The average sound pressure level of CPAP machines is about 30 decibels, so this device is quieter than most.
    • Ease of Use: The crisp LCD interface is user-friendly and easy to read. When the machine is in standby mode, you can view the time, room temperature, and humidity level. You can also view your compliance data and adjust the preheat and ramp mode settings using the interface.
    • Portability: The Luna G3 is not as portable as many competing CPAP machines — particularly those specifically intended for travel. However, at less than 4 pounds, the device is fairly lightweight and easy to reposition during the night. You can remove the water chamber if you need to disassemble the machine prior to packing.
    • Pressure Settings: The Luna G3’s pressure level can be set between 4 and 20 cm H2O in 0.5 cm H2O increments. This range is standard for most CPAP machines. Since the device operates at a fixed pressure setting, you’ll need to speak with your physician if you need the pressure adjusted.
    • Air Temperature Control: The heated humidifier helps warm up the air prior to delivery, and the tubing keeps the air warm as it is funneled into your face mask. Some CPAP users breathe easier with heated air. The preheat function allows you to begin warming up the water prior to your bedtime.
    • Humidity Control: The AutoHumidity control adjusts humidity levels based on your surroundings. This helps provide the right level of moisture to promote comfortable breathing. The heated tubing keeps the humidified water at a consistent temperature to help prevent rainout, which is when water droplets build up in a CPAP mask.
    • Compatibility: The Luna G3 is designed for universal mask compatibility. As such, you can use any full-face, nasal, or nasal pillow mask with the machine’s connective tubing.
    • Maintenance: The company recommends cleaning the tubing and the humidifier’s water chamber on a daily basis. You should also clean your mask and other accessories daily with warm water and mild soap. The filter should be replaced every six months at minimum, though it may need to be replaced sooner depending on air quality. Store all device components out of direct sunlight.

    Sleep Foundation Special Offer

    Use this link for the most current React Health discount

    Trial, Warranty and Shipping Policies


    As with other CPAP machines, you’ll need a doctor’s prescription to purchase the Luna G3. The device is sold by authorized CPAP machine retailers.


    Shipping costs and delivery times for the Luna G3 CPAP Machine depend on the seller you choose, but many offer free standard ground shipping. The device will most likely arrive disassembled, so you’ll need to install the humidifier’s water chamber and connective tubing prior to first use.

    Sleep Trial

    Some CPAP machine retailers let you return the Luna G3 unused within a certain time frame. For others, the sale is final and returns are not allowed. Regardless of the seller’s specific policies, you won’t be able to return a used machine because it is considered a medical device.


    The standard manufacturer’s warranty for the Luna G3 CPAP Machine is two years. During this time, you may be able to exchange the device for a new model or return it for a refund if a structural defect is found. Most retailers honor this two-year warranty, but be sure to read the fine print.

    Still have questions?

    Our product experts have extensive experience testing just about every sleep product on the market. Send an email to [email protected] or call us at (877) 672-8966 with your questions and we’ll help you find exactly what you’re looking for.

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