How to Choose a CPAP Machine: A Beginner's Guide

Short version

If your prescription says “CPAP,” you’ll be choosing among fixed-pressure or auto-adjusting (APAP) machines that can run in a fixed mode — most modern APAP machines can do both, so they tend to be the flexible default choice. If your prescription specifically calls for BiPAP, that’s a different category of machine your DME will set you up with directly. Beyond that, the meaningful differences between machines are humidifier quality, noise level, size, and how easy it is to get your own data off the device. This guide walks through those decisions so you can talk to your DME provider with a clearer sense of what you actually care about.

I started CPAP therapy in 2023, and when I was first handed a prescription, I had no idea that “CPAP machine” wasn’t really one product category. Here’s what I’ve learned since, from the patient side of things — not the clinical side.

The prescription decides the category, not you

This is the first thing to get straight: your sleep clinician’s prescription determines what kind of machine you need, and your DME provider fills that prescription. You don’t get to shop around for a different therapy type the way you’d shop for a phone. What you do have some say in is which specific machine model delivers that therapy, and which features it has.

Prescriptions generally fall into a few categories:

• CPAP (continuous positive airway pressure): delivers a single, steady pressure all night, set after a titration study or based on data from an auto-adjusting trial. AASM’s overview of PAP therapy explains the basic categories of positive airway pressure devices.
• APAP (auto-adjusting PAP): varies pressure breath-by-breath within a range your clinician sets, responding to signs of airway narrowing or events. Many machines sold as “APAP” can also be locked into a fixed single pressure, which is why they’re often recommended as an all-purpose choice — your clinician can decide which mode fits your prescription.
• BiPAP (bilevel PAP): delivers one pressure on inhale and a lower one on exhale, and is generally prescribed for people who don’t tolerate CPAP well, who have certain breathing patterns, or who have specific respiratory conditions. This is a different machine category, not just a “setting,” and it comes from your clinician’s specific order.

If you’re not sure which of these your prescription is for, that’s a question for your sleep clinician or DME provider before you get deep into comparing models — it changes the shortlist entirely.

Fixed CPAP vs. APAP, in plain terms

If your prescription allows either, here’s the practical difference from a user’s chair, not a technical one.

A fixed CPAP machine holds one pressure all night, the number your clinician determined works for you. It’s simple and predictable. Some people find a steady pressure easier to fall asleep with, since there’s no sensation of pressure changing as you breathe.

An APAP machine adjusts within a range, increasing pressure when it detects signs of airway resistance and backing off when things are calm. Some clinicians prescribe APAP because sleep position, alcohol, congestion, and even weight changes can shift what pressure a person needs night to night, and an auto-adjusting device can respond to that automatically. Because most APAP machines can also be configured to run at a single fixed pressure, they’re often positioned as the practical default for someone starting out — you get flexibility without giving up the option of a steady pressure if that’s what’s prescribed.

The tradeoff some people report with APAP is that the pressure changes are more noticeable, at least at first, which can take getting used to. This is exactly the kind of thing worth mentioning to your DME provider if it’s disrupting your sleep — they may have a specific adjustment in mind, but it’s not something to change yourself.

The ResMed AirSense 11 AutoSet is a common example of this category: it’s sold as an APAP but can be set up to run in either mode depending on what’s prescribed.

BiPAP: a different category, not a step up

It’s tempting to think of BiPAP as “the more advanced machine,” but that’s not quite right. BiPAP is generally prescribed for specific situations — for example, some people find it hard to exhale against a single high pressure, or have a breathing pattern where two pressure levels work better than one. AASM material on PAP therapy types is a reasonable starting point if you want to understand the reasoning, but the decision itself belongs to your sleep clinician based on your diagnostic testing. If your prescription says CPAP or APAP, that’s not something to second-guess into a BiPAP purchase on your own.

Once you know the category: what actually varies between models

Assuming your prescription is for CPAP or APAP, here’s where your personal preferences start to matter.

Humidifier and heated tubing

Nearly all modern machines include a heated humidifier, and most people find it makes a real difference in comfort — dry mouth and nasal irritation are common complaints without one. Some machines offer heated tubing in addition to a heated humidifier chamber, which helps prevent “rainout” (condensation collecting in the hose), especially if your bedroom is cooler than the air coming out of the machine. If you tend to sleep in a colder room, or you’ve had rainout problems before, ask specifically whether the model you’re considering supports heated tubing rather than just a heated chamber.

Noise level

CPAP machines are generally quiet, but “quiet” varies, and if you share a bed, a few decibels can matter. Manufacturers publish sound level specs in their instructions for use — worth a look if you or a partner are noise-sensitive. In practice, most current-generation machines from major brands are quiet enough that mask leaks or tubing bumps make more noise than the motor itself.

Size and travel

If you travel often, size and weight matter more than people expect before they’ve actually had to pack a CPAP for a work trip. Some manufacturers offer separate compact “travel” machines, while others make their standard machine small enough to double for both. If you’re only weighing one machine for both home and travel use, check the dimensions and weight against your typical luggage situation, and see whether it comes with (or supports) a padded travel case.

Data access: on-device, app, or SD card

This is the one people tend to overlook until later, and I’d argue it’s one of the more important practical differences between machines.

Every modern machine tracks basic therapy data — usage hours, an estimated apnea-hypopnea index (AHI), leak rate — and shows a simplified version on the device screen or in a companion app. That’s enough for a lot of people. But if you want to dig into your own data in more detail (which I found genuinely useful for spotting mask leak patterns and understanding good vs. bad nights), you’ll want a machine that either:

• Supports third-party software like OSCAR by exporting detailed data to an SD card, or
• Has a companion app that at least gives you daily summaries, even if it doesn’t hand over the raw data.

Some manufacturers’ apps show only high-level summaries and don’t provide a way to export the underlying data, while others make the SD card data straightforward to pull and read. If self-tracking matters to you, it’s worth asking your DME specifically whether the model in question supports SD card data export, since this isn’t always obvious from marketing materials.

Mask compatibility

Not every machine works identically well with every mask, though most current CPAP and APAP machines use a standard connector that fits the vast majority of masks on the market. Where compatibility issues tend to show up is with specific comfort features — for example, some machines have settings tuned for particular mask types, or ship with tubing connectors sized for the manufacturer’s own mask line. If you already know which mask works for you, or if your DME has a strong recommendation, ask whether the machine you’re considering has any known quirks with that specific mask before you commit to both at once.

What actually makes a machine “good for beginners”

There’s a reasonable case that the single most important trait for someone just starting therapy is a good humidifier and a comfortable, predictable pressure ramp, more than any bells and whistles. Advanced data features and travel size don’t help much if you’re not using the machine because it feels rough on the first few nights. Some things that seem to help people stick with therapy early on:

• A working heated humidifier, since dryness is one of the more common early complaints.
• A gradual pressure “ramp” feature, which starts at a lower pressure and increases over a set period as you fall asleep — useful for people who find the full prescribed pressure hard to fall asleep against initially. Ask your DME whether this is available on your device and how it’s typically used.
• Clear, simple feedback (even just the on-device summary screen) so you have some sense of how the previous night went without needing to become a data expert right away.

None of this replaces a fitting mask, which honestly tends to matter more to comfort than the machine itself for a lot of people.

When to talk to your doctor or DME

• If you’re unsure whether your prescription is for CPAP, APAP, or BiPAP, ask before comparing machines — it changes the entire shortlist.
• If you’re having trouble tolerating the prescribed pressure, mention it rather than adjusting anything yourself; there may be ramp settings, humidification changes, or a different pressure range worth discussing.
• If data access matters to you, ask specifically whether a machine you’re considering supports SD card export or detailed app data, since this varies by brand and isn’t always advertised clearly.
• If you travel frequently, ask whether your DME can provide or recommend a travel-appropriate option, since not all insurance plans cover a second machine.

Choosing a CPAP machine can feel like a bigger decision than it needs to be. The prescription narrows the field to one category, and after that, you’re really just picking the version of that category that fits how you sleep, travel, and want to track your own progress.