Both the AirMini and the Z2 are highly capable travel CPAPs worthy of your consideration. But they have important differences. Let’s explore these machines in some detail.

First, we’d like to give you a bird’s eye view of the machines in comparison in the table below.

ResMed AirMini vs HDM Z2 Travel APAP Comparison Chart

	ResMed AirMini	HDM Z2 Auto
Release Date	May 2017	Mar 2019
Dimensions (Size)	5.4 x 3.3 x 2.1 inches	6.48 x 3.30 x 2.02 inches
Footprint	17.82 sq inches	21.39 sq inches
Weight	10.6 Oz	10.4 Oz
Humidification	HumidX & HumidX Plus Heat Moisture Exchangers (HME)	Waterless – Heat and Moisture Exchanger capsule
Quietness (Noise level)	30 dBA	26 dBA
Operating Pressure Range	4-20 cm H2O	4-20 cm H2O
Operation Mode	CPAP/APAP	CPAP/APAP
Power	100-240V, 50-60Hz	100-240V, 50-60Hz
Integrated Battery	No	Optional (at $359 extra)
Ramp Time	0-45 minutes	0-45 minutes
Mobile Device App	MyAir (Apple 4.6 stars, Android 4.4 stars)	Nitelog (Apple 1.5 stars, Android 2 stars)
Altitude Adjustment	Automatic up to 8500 Feet (2591 m)	Automatic up to 8000 Feet (2438 m)
Bluetooth	Yes	Yes
Leak Compensation	Yes	Yes
For Her Mode	Yes	No
Expiratory Pressure Relief	Yes (EPR)	Yes (Z-Breathe)

Similarities between ResMed AirMini and HDM Z2

Size and Weight

In terms of physical characteristics, the machines weigh almost the same at just over 10 oz and are practically weightless, which is a very welcome aspect of any travel CPAP.

Both machines are very small. In fact, the AirMini was considered the smallest travel CPAP until the advent of the Transcend Micro which is now the tiniest CPAP on the planet.

So, while there is a small difference in footprint, and the Z2 is a tad bigger than the AirMini, both are very small machines that are easy to carry around.

Humidification

Both the AirMini and the Z2 offer integrated waterless humidification. Both use special Heat Moisture Exchange filters (HME) filters that capture the heat and moisture of your own breath and serve it right back to your airways.

While not a complete replacement for a full blown humidifier, HME is a neat little system that works.

Comfort Features

Both the AirMini and the Z2 have AutoPAP functionality. This means that they can provide variable pressure throughout the night. This is a big deal, as you probably already know.

Both machines offer the following comfort features:

Ramping
EPR (Expiratory Pressure Relief)
Leak compensation

Ramping allows the machine to start you off on lower pressure and only begin increasing it after a set period, which is up to 45 minutes on each machine. This enables you to fall asleep at a lower pressure, making it a great comfort feature.

Expiratory Pressure Relief lowers the pressure while you exhale, further easing your CPAP therapy.

And leak compensation detects mask leaks and increases air pressure to compensate for the loss.

Bluetooth Connectivity

Both AirMini and Z2 connect to smartphones via bluetooth, enabling you to monitor your sleep data. Without getting into all the features of each sleep app – MyAir for AirMini and Nitelog for the Z2 – we’ll mention an important consideration.

When technology works well, it is great and a boon to humanity. When it doesn’t, it is of not much use. The average rating of the MyAir app is 4.5 stars in the Apple Store and Google Play. The Nitelog app’s average rating is 1.75 stars. ‘Nuff said.

Other Similarities

Both machines have universal power at 100-240V, 50-60Hz, which means that you can use them in any country. You may only need a power adapter to fit power outlets in some countries. But you will not need a power converter, which is great because one of those can add significant weight to your luggage.

Both units operate at a Pressure Range of 4-20 cm H2O. And both have automatic altitude adjustment of 8,500 ft (AirMini) and 8,000 ft (Z2).

Differences between ResMed AirMini and HDM Z2

Noise Level

Perhaps because the Z2 is a newer machine (it is 2 years younger than the AirMini), its technology has allowed for quieter performance. While AirMini is not exactly loud at 30 decibels, the Z2 operates at 26 decibels, which is virtually whisper quiet.

Integrated Battery

If you need to use a battery with your travel CPAP, battery options are available for both the AirMini and the Z2. However, only the Z2 offers an integrated battery unit.

That said, let’s look at the options in some detail.

The Z2 is complemented by an optional Powershell battery module. And while it is an “integrated” module, it does not disappear in the body of the Z2. Instead, it is a battery unit that weighs an additional 15.5 ounces and is 8.25 x 4 x 3.25 inches in size.

You have an option of purchasing it at $359 extra when ordering the Z2, which is about $90 less expensive than if you buy it separately later.

Conversely, the AirMini can be powered by a third-party battery, such as the Medistrom Pilot-24. You will also need the 65W ResMed AirMini DC/DC Converter to connect the battery to the unit.

Pricewise, the battery units for each of the machines come out to about the same amount. Although you may find the integrated unit for the Z2 somewhat more elegant.

For Her Mode

Finally, the AirMini offers the AutoSet For Her mode of operation that is specifically geared towards female users. This feature is absent from the Z2.

The For Her algorithm is more sensitive to flow events, providing smoother sleep for women.

Our Verdict

So, which machine should you purchase in the end?

Well, the features are all laid out before you. The AirMini is a little more expensive than the Z2 at a price tag difference of about $110. But it has a For Her mode, which is something to consider if you’re a woman and somewhat extra sensitive to CPAP air pressures.

If you want to monitor your sleep data, you’ll probably find the MyAir app easier to use. So, if you’re not overly sensitive to noise (since the AirMini is a bit noisier) and don’t mind the slightly higher price tag, then the more modern design of the AirMini may just sway you its way.

And whichever machine you end up choosing, sleep tight!