The AirMini by ResMed, the Z2 Auto by Breas Medical, the Transcend 3, and the new Transcend Micro are mighty travel CPAPs loaded with features. Let’s examine the similarities and differences among these machines in detail.

AirMini, Breas Z2, Transcend 3 miniCPAP Auto, and Transcend Micro Travel APAP Comparison Chart

ResMed AirMiniBreas Z2 AutoTranscend 3 miniCPAP AutoTranscend Micro
Release DateMay 2017Mar 2019July 2019July 2022
Dimensions (Size)5.4 x 3.3 x 2.1 inches6.48 x 3.30 x 2.02 inches7.4 x 3.7 x 3.7 inches3.6 x 3.6 x 2.4 inches
Footprint17.82 sq inches21.39 sq inches27.38 sq inches12.96 sq inches
Volume37.4 cubic inches43.2 cubic inches101.3 cubic inches31.1 cubic inches
Weight10.6 oz10.4 oz10.4 oz7.74 oz
HumidificationHumidX & HumidX Plus Heat Moisture Exchangers (HME)Waterless – Heat and Moisture Exchanger capsuleNoneWaterless – Heat and Moisture Exchanger capsule
Quietness (Noise level)30 dBA26 dBA26 dBA27 dBA (± 2 dBA)
Operating Pressure Range4-20 cm H2O4-20 cm H2O4-20 cm H2O4-20 cm H2O
Power100-240V, 50-60Hz100-240V, 50-60Hz100-240V, 50-60Hz100-240V, 50-60Hz
Integrated BatteryNoOptional at extra costNoNo
Ramp Time 0-45 minutes5-45 minutes0-45 minutes0-45 minutes
Mobile Device AppAirMini appNitelogNoneMySleepDash
Altitude AdjustmentAutomatic up to 8500 ft (2591 m)Automatic up to 8000 ft (2438 m)Automatic up to 8000 ft (2438 m)Automatic up to 8000 ft (2438 m)
Leak CompensationYesYesYesYes
For Her ModeYesNoNoNo
Expiratory Pressure ReliefYes (EPR)Yes (Z-Breathe)Yes (EZEX)Yes (AirRelief)

AirMini, Z2, Transcend 3, Transcend Micro – Size and Weight

Three of the machines (all besides the Micro) weigh similarly at just over 10 oz and are already feather-light, which is what you want in a travel CPAP.

Of course, the Transcend Micro introduced a brand new level of lightness to the world of travel CPAP. It weighs just under 8 oz. So, make sure you actually have it in your bag or purse before you step out the door because you’ll barely feel its absence in case you forget to take it with you. 

Until the release of the Transcend Micro, the AirMini was the smallest travel CPAP on the market. But, in fact, all four machines are very small. If you glance at the chart above, you’ll see that the Transcend 3 has the largest footprint at just over 27 sq inches. But even then, it is only slightly larger than the Breas Z2 Auto

So, despite some differences in footprint, all four machines are small and easily portable. However, when you look at the volume that each machine occupies in your bag, you’ll notice quite a contrast between the Transcend 3 and the other three machines. 

(Please note that the actual volume each unit occupies is smaller than the number given in the table above because these machines are not solid rectangular blocks but have rounded shapes and curves.)

So, if your carry-on luggage space is limited, this is something to consider since the overall volume of the Transcend 3 is nearly three times that of either the AirMini or the Micro. It’s 2.5 times the volume of the Z2. 


The AirMini, the Z2, and the Micro feature integrated waterless humidification. All three use Heat Moisture Exchange (HME) technology. HME filters capture the heat and moisture from your breath and return it to your airways during the next breath. 

Although not a full substitute for a regular humidifier, HME does the job for a time. Note that HME filters need to be replaced every week and don’t work as well when wet. They are designed to be replaceable and are used in healthcare settings to provide short-term humidity.

The Transcend 3 does not have its own HME but it’s compatible with the universal HME filter for the Breas Z2 Auto travel CPAP.

Comfort Features

All four machines have both manual CPAP and AutoPAP functionality. This means that they can provide both static and variable pressure during a night of sleep. 

All four machines offer these comfort features:

  • Ramping
  • Exhalation Pressure Relief

Ramping starts you off at a lower pressure and only begins to increase it after a period that you can set—up to 45 minutes on each of the machines. This means that you can fall asleep comfortably at a lower pressure and only then have your prescribed pressure applied.

AutoRamp takes this feature a step further by detecting when you have fallen asleep and only then beginning to increase the pressure. The ResMed AirMini and Transcend Micro are the only machine in this lineup that offers AutoRamp. 

Exhalation pressure relief makes your CPAP therapy even more comfortable by lowering the air pressure at exhalation. This feature is present in all four machines – under different names. ResMed calls it EPR on the AirMini. It is Z-Breathe on the Z2. And EZEX is the name of the feature on the Transcend 3 while the Micro calls it AirRelief. 

Leak compensation is another comfort feature designed to make your night’s sleep even smoother. It detects any mask leak rises during the night and increases air pressure to compensate for the loss. All of the travel CPAP machines have this feature.

Bluetooth Connectivity

All of the machines except the Transcend 3 miniCPAP can connect to smartphones via Bluetooth. The Bluetooth-supported machines are compatible with mobile apps that lets you track your CPAP data and make adjustments to comfort settings such as ramp and exhalation pressure relief. 

The Z2 Auto is the only machine where you can adjust comfort settings from a smartphone app and directly on the unit. Without getting into all the features of each sleep app, we’ll mention an important consideration: if you want to use the AirMini, you must download the AirMini app. You cannot make any machine adjustments, including setting up your therapy pressure, without the AirMini app. If you buy the AirMini from RespShop, we’ll set your ResMed travel CPAP to your prescription settings but you’ll still need to download the app to make future adjustments.

You can change comfort settings on the Transcend Micro using the MySleepDash app or the Transcend desktop software. If you’re using the desktop software, you’ll need a USB-C cable to connect your Micro CPAP to the computer. It’s worth noting that this desktop software is only compatible with Windows OS. You can also use the Transcend desktop software to adjust settings for the Transcend 3 miniCPAP Auto.

Noise Level

The smaller the machine, the more noise it generally produces. This is due to the lack of space within the machine for sound-muffling padding. 

The Breas Z2 is a newer and slightly bigger machine than the AirMini, so its technology enables it to operate more quietly. The noise level of the Transcend 3 is identical to the Z2 at 26 decibels. And finally, the Transcend Micro operates at 27 decibels, give or take two decibels. Our Sleep Science Coach, Susan, found the Micro to be just a little louder than machines that run at 26 decibels. 

Please keep in mind that the Micro comes with a muffler kit that will help mitigate some of the noise if you happen to be sensitive to sound. 

Battery Options

All of the four machines are compatible with CPAP batteries or powerbanks. Please note that only the Breas Z2 Auto offers an integrated battery unit. But let’s explore the available battery options. 

First, let’s introduce the Zopec EXPLORE 5700 Universal CPAP Battery. This rechargeable lithium-ion battery works with any CPAP machine. It can be connected to each of our travel machines directly—no adapter cable is needed.

In addition, each of the machines has other battery options.

The Z2 Auto has an option for the Powershell battery module. This is the only integrated power module available among our travel CPAPs. You can purchase it when ordering the Z2 for some savings, or you can buy it later. 

In addition to the Zopec EXPLORE 5700, the AirMini can also be powered by the Medistrom Pilot-24-Lite CPAP Battery. If you wish to connect it to your car cigarette lighter, you will need the 65W ResMed AirMini DC/DC Converter.

The Transcend machines can be powered by the Transcend P8 Travel Multi-Night CPAP Battery

Finally, as mentioned before, the Zopec EXPLORE 5700 is compatible with all machines in our lineup (and with all CPAP machines), making it a great investment as it won’t become obsolete when you eventually replace your travel CPAP. Check out our CPAP battery review for a detailed comparison of our top battery picks including the Zopec EXPLORE 5700, Transcend P8, Medistrom Pilot-24-Lite and more.

AutoSet For Her Mode

The AirMini is the only machine in the lineup that offers the AutoSet For Her mode of operation that is specifically designed for women. The For Her algorithm is more sensitive to flow limitation and responds faster to provide for a smoother and deeper quality of sleep for women. 

Other Features

All four units have universal power at 100-240V, and 50-60Hz, which means that you can use them anywhere in the world. However, you may need a plug adapter because power outlets vary depending on where you travel. 

All four units operate within a pressure range of 4-20 cm H2O. All four are also equipped with automatic altitude adjustment of 8,500 ft (ResMed AirMini) and 8,000 ft (Breas Z2 and the Transcend machines). 

Our Verdict

So, what is the best travel CPAP machine? The answer depends on what you value most. If the price is the main concern, then you’ll probably want to steer clear of the ResMed AirMini, which tends to be priced about $100 to $200 more than the other options. However, the AirMini has the most user-friendly smartphone app and is the only machine that features a therapy mode designed specifically for women.

If you’re looking for a no-frills machine to use when you’re away from home, the Breas Z2 Auto and the Transcend 3 miniCPAP Auto are great options. They’re both moderately priced and offers you the option to track sleep therapy data on your smartphone or computer. It’s worth noting that neither machines feature AutoRamp technology, and only allow you to set ramp time.

Now, if your priority is finding a CPAP machine that is small and compact, the Transcend Micro may be your top pick. It is about the size of a softball and you can easily slip this into an overnight bag while leaving plenty of room for other essentials. Although the Micro is new to the market, reviews are beginning to trickle in, and people seem to love it. Explore all the features of this small yet mighty travel CPAP in our Transcend Micro CPAP review.

If you have any questions about travel CPAP machines, feel free to get in touch using one of the options below. The RespShop medical staff is happy to help you with your sleep apnea journey.