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APAP vs. CPAP: What Is APAP and How Is It Different Than CPAP?

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graphic detailing the difference between apap and cpap

If you’ve been recently diagnosed with Obstructive Sleep Apnea—or if you think you have sleep apnea but are not yet diagnosed—you may be feeling confused about the differences between an APAP vs. CPAP. APAP and CPAP machines are sometimes referred to as PAP machines or Positive Airway Pressure machines.

Most people with sleep apnea use a CPAP (Continuous Positive Airway Pressure) machine, but a CPAP machine isn’t the ideal choice for everyone. Individual treatment needs can vary based on your specific needs. Some people with sleep apnea will see better results by using a BiPAP machine, and others will benefit more from using an APAP machine.

In this article, we’ll look at what an APAP machine is, how it works, why an APAP may be the best sleep apnea machine for you, how an APAP compares to a CPAP, and what the benefits and potential drawbacks are from APAP therapy.

We’ve also included some of our top APAP recommendations at the end of this article.

Let’s dive in!

What’s an APAP Machine, and How Does It Work?

The acronym APAP is short for Automatic Positive Airway Pressure.

APAP can also be referred to by the following names:

  • Auto Adjusting CPAP
  • Auto Titrating CPAP
  • Self Adjusting CPAP
  • Auto PAP
  • Automatic CPAP
  • Auto
  • SmartPAP

Auto Adjusting CPAP machines or APAPs help people with sleep apnea breathe easier and sleep better by keeping your airways open through the delivery of pressurized air, adapting the amount of pressure on a breath-by-breath basis, even as those needs change throughout the night as you move in and out of the various stages of sleep or as you change sleeping positions.

An APAP machine uses algorithms, which sense minute changes in your breathing then adjusts itself to provide the best pressure setting for your specific sleep apnea therapy requirements.

The general principle behind CPAP, BiPAP, and APAP are the same in all three cases: pressurized, filtered air keeps your airway from collapsing during sleep, allowing you to breathe without interruption.

By using a sleep apnea machine like an APAP, you’ll be able to breathe without apnea events waking you up. Apnea events are cessations of breathing that lead to multiple nighttime awakenings per hour throughout the night. Sleep apnea machines can also help to treat upper airway resistance syndrome (UARS), a precursor to sleep apnea that narrows, rather than blocks your airway.

All PAP therapy machines consist of three main components:

  1. A Motor That Pressurizes, Filters, and Humidifies (if You Want It to) Room Air
  2. Tubing Through Which the Air Travels Until It Gets to Your CPAP Mask
  3. A Sleep Apnea Mask That You Wear While Sleeping

What’s the Difference Between CPAP and APAP?

Sleep apnea experts frequently hear this question: “APAP vs. CPAP: what’s the difference between these sleep apnea machines?” If they all do the same thing, why choose an APAP machine for my sleep apnea instead of a CPAP? The difference is in the air pressure settings.

The main difference between APAP and CPAP machines is that CPAPs have a fixed pressure setting, and APAPs adjust to different pressures automatically based on your nightly needs. The air pressure delivered from both APAP and CPAP machines functions similarly by providing a continuous stream of pressurized air to prevent your airway from collapsing. The consistent stream of air helps those with sleep apnea breathe freely throughout the night, leading to a good night’s rest.

CPAP: Single Pressure Setting

CPAP therapy, the gold standard for treating most cases of Obstructive Sleep Apnea, provides a continuous, steady flow of air at a single pressure. This pressure setting is the exact level of air pressure required to keep your airway clear of obstructions. A CPAP wearer will have their own individual pressure setting, which is determined by their sleep specialist during their CPAP titration study. A CPAP titration study is an overnight study where you wear your sleep apnea mask to sleep, and the technologists observe you and adjust your air pressure until it’s precisely what you need.

This set air pressure level can be adjusted in the future if needed. For example, if your sleep apnea worsens and you need more air pressure to clear your airway, your pressure can be increased. However, these pressure changes must be prescribed and changed by your doctor or sleep technician in the sleep clinic.

Related Reading: Best CPAP Machines of 2021: Our Top-Rated Machines Ranked!

APAP: Automatic Range of Pressures

As it states in the Journal of Thoracic Disease, “Instead of operating at a set pressure, APAP monitors a patient’s respiratory activity in order to provide the lowest level of PAP necessary to eliminate respiratory disturbances. Algorithms are designed to increase pressure when events are noted and to decrease pressure slowly if events have not occurred for a period of time.”

The pressure delivered by an APAP automatically changes as needed to deliver the minimal pressure required to maintain your airway. Your doctor will set a minimum air pressure setting range and a maximum air pressure setting range. After that, sophisticated algorithms automatically determine which level of air pressure you need at any given moment during the night, and the APAP machine makes the necessary adjustments.

With an APAP machine, no additional titration study is required to change your pressure setting since it is based on a range. This type of sleep apnea therapy is helpful for people with varying breathing patterns. If for some reason you don’t respond well to APAP therapy, your doctor can reset the machine to function like a CPAP, delivering continuous pressure instead.

You’re now probably asking yourself why would my pressure need to be adjusted? Great question! As time passes, your body and lifestyle change. For your sleep apnea therapy to be successful, you may need to increase or decrease the pressure of your machine periodically.

Depending on your lifestyle and the transformations you go through in your sleep apnea therapy journey, you may need to adjust your pressure several times during the course of your treatment. Using an APAP machine can cut down on doctor’s visits to adjust pressure.

APAP vs CPAP: Which One Is Right for You?

A CPAP machine may be adequate if your breathing patterns do not change much throughout the night or with changes in position. APAPs are often better than CPAPs because they can detect subtle changes in your sleep behavior and sleep positions that require different pressure settings. For example, if you have apnea events more often while sleeping on your back than when you sleep on your side or stomach, the APAP machine can adjust the air pressure accordingly.

An APAP can treat your sleep apnea and bring you relief from the snoring, choking, and drowsiness associated with this common sleep condition.

If both machines do roughly the same thing, why would you choose one over the other? There are a few key differences that may lead you to choose an APAP over a CPAP:

  • Automatic Adjustments to Pressure. The pressure that’s right for you today may not be the pressure that’s right for you tomorrow as your body changes. In some cases, lifestyle changes in addition to any changes in medical conditions may also impact the pressure you need to make your sleep apnea therapy a success.
  • Convenience. An APAP automatically adjusts the pressure settings based on your breathing and does not require as many adjustments to the pressure as a CPAP would. It’s beneficial to have a device that automatically adjusts to the pressure you need on a nightly basis.

Cost: Is an APAP Machine More Expensive Than a CPAP Machine?

One other factor to consider in choosing APAP vs CPAP is the cost. APAP devices themselves do cost more than CPAP devices, but the long-term cost benefits can more than make up for the cost differences at the start. APAPs also result in fewer doctor’s visits because they aren’t set on one specific pressure like CPAPs are.

Also, the increased comfort when you choose APAP may improve your CPAP compliance, which can mean fewer follow-up appointments and better insurance coverage for your therapy.

APAPs can cost $450 to nearly $900, depending on the features and size. For the most current pricing, you can view our top-rated APAP machines, which show the current prices of the most popular APAPs. APAPs also come in travel sizes, so you can sleep well while on the road.

Justifying the cost: An APAP can cost as much as $300 more than a CPAP machine. For some customers, it’s a small price to pay for the comfort features, but for others, the cost of an APAP may be a barrier.

CPAP vs. APAP: Benefits, Uses, and Drawbacks

APAPs are more versatile than CPAPs. As with most things in the world, there are pros and cons when it comes to APAP therapy.

Benefits of APAP Machines

Perhaps the chief benefit of using an APAP is that you do not need to stay on the fixed higher pressure of CPAP machines over the course of a single night. Using an APAP machine means your overall pressure can be significantly less. For some people who are sensitive to higher air pressures (for example, if you feel claustrophobic), this variable pressure setting may mean more comfort and a better night’s sleep.

APAP is also helpful if you experience night-to-night-variability in your air pressure needs. For example, if you have seasonal or situational allergies or a cold, sometimes you’ll need more or less air pressure, depending on your level of congestion.

If you’ve been drinking alcohol, you may need more air pressure that night to compensate for the resulting flaccidity of your muscle tissue since alcohol is a depressant.

The APAP can adjust on its own for these conditions, whereas CPAP and BiPAP cannot.

Top Four Reasons To Consider an APAP Over a CPAP

  1. You Can Use an APAP as a CPAP If You Want. Most APAP units can also be set to CPAP mode, allowing you to discover which titration therapy works best for you. Who doesn’t love options?
  2. If Your Breathing Changes Throughout the Night, You’re Covered. Most people don’t have the same breathing patterns throughout the entire night, and an APAP adjusts on the go to fit your needs.
  3. An APAP Adjusts if You’re Sick. If you have a cold or suffer from allergies, you can become congested and breathing can be more difficult. Colds happen to everyone, and it’s nice to have a machine that can adjust automatically if you’re more congested than usual.
  4. Body Changes Require Different Settings. Changes in your health such as weight loss or weight gain can require different pressure settings, and an APAP will automatically make those adjustments within the range your doctor has set.

Uses of APAP (Reasons and Indications)

You might choose APAP therapy if you have one of the following situations or indications:

Your Apnea Events Increase in REM sleep. During REM sleep, your throat muscles relax and may become flaccid or paralyzed, leading to airway obstruction. If you use a CPAP, your machine is set to provide you sufficient air pressure to overcome this obstruction—but that air pressure stays with you all night long, even during the other sleep stages.

Some CPAP wearers find this constant high air pressure to be uncomfortable. APAPs, however, can adjust by delivering higher pressure settings during the REM stage and lower pressure during the other sleep stages.

You Switch Sleeping Positions During the Night. Are you a side or back sleeper or do you switch between each position? Moving around at night can lead to changing pressure requirements. Some people with sleep apnea need a higher pressure setting when sleeping on their backs versus sleeping on their side. When sleeping on your back, gravity pulls the loose tissue toward the back of your throat, creating a blockage. An APAP can adjust automatically by reducing the air pressure setting when you roll onto your side.

You’ve Been Diagnosed via a Home Sleep Test (HST). If you live far away from a sleep center or your health insurance does not cover the cost of a full polysomnogram and overnight sleep study at a sleep center, perhaps you’ve opted for a home sleep test as an alternative. If your HST diagnoses you with sleep apnea, you may be able to start out treatment quickly with an auto-adjusting APAP.

Drawbacks and Side Effects of APAP Therapy

We already mentioned cost as a notch drawback against APAP machines, but what are some other things you should be aware of with APAP?

  • APAP Isn’t Ideal for CPAP Wearers With Certain Health Conditions. If you have any respiratory or cardiac ailments, APAP may not be the best fit due to the frequent pressure adjustments.
  • Air Leaks. An APAP gives your mask seal little room for failure, so be sure that you find a mask that is not only comfortable but also fits securely on your face. If the mask seal isn’t secure, it can be problematic if you tend to move a lot during sleep or if you need a higher air pressure. This may be an easy-to-fix issue, depending on the type of machine you get. For instance, every morning the ResMed AirSense 10 listed below gives you an on-screen summary of the previous night’s sleep metrics, including whether or not your mask seal of the previous night was adequate.

The 3 Best APAP Machines

If you’ve decided APAP is best for you, we’ve collected a group of our customer’s favorite APAP devices to make shopping for your first or next APAP a breeze!

ResMed AirSense 10 AutoSet

The AirSense 10 AutoSet CPAP Machine with HumidAir Heated Humidifier is one of our most popular APAP machines! The AirSense 10 builds on the reliable and advanced features of the S9 line but a built-in HumidAir Humidifier has been added to keep your sinuses moisturized. The AirSense 10 features a sleek design that is 23% lighter than previous machines.

Built-In Heated Humidifier
Color LCD Display
One of the Quietest APAPs on the Market
Optional Heated Hose
For Her Version

Why Do Our Customers Love the AirSense 10? The built-in heated humidifier is a game-changer when it comes to the AirSense 10. The quiet machine takes up a small footprint on your nightstand or in your travel bag. The AirSense 10 is a great machine for both at home or on-the-go.

ResMed AirMini

Wanting a machine to take almost anywhere? Weighing only 0.66 pounds, the AirMini AutoSet Travel CPAP Machine is small enough to almost fit in the palm of your hand. The AirMini uses a 20W power supply to further minimize the size of the travel machine. Use the AirMini by ResMed smartphone app to track your therapy progress and adjust your machine settings.

Lightweight and Compact APAP
FAA Compliant
Waterless Humidification System
AirMini Mobile App

Why Do Our Customers Love the AirMini? In the travel category, the AirMini is one of the most popular machines on the market, and it’s easy to see why. Put this machine in your carry-on, backpack, or purse and head on your next adventure. For many people who have the AirSense 10 as their home machine, the AirMini is their travel machine of choice. This tiny, lightweight, and quiet machine can connect via Bluetooth to your phone or tablet so you can access your data and settings on the AirMini app.

Luna II Auto CPAP Machine with Humidifier

The Luna II Auto CPAP features a built-in humidifier, is capable of wireless data tracking and sharing, and has the same popular features our customers love in other industry-leading brands. Auto-start, mask leak alerts, up to 60 minutes of Ramp time, and the crystal clear LCD display are just a few of the things that make the Luna II great for any of your therapy needs. Combined with a lower-than-average price tag, it’ll be great for your wallet, too.

Turns On Automatically
Ramp Feature Slowly Builds Up to Full Pressure
Color LCD Screen Provides Helpful Sleep Data
CPAP Mode Available if Needed

Why Do Our Customers Love the Luna II Auto? The sleek and modern Luna II provides all of the powerful features you’d expect from an industry leader such as ResMed or Philips Respironics in a more affordable package. It features Reslex Expiratory Pressure Relief, Auto Start, Mask Leak Alerts, Ramp, Wireless Data Tracking and Sharing, and a Built-In Heated Humidifier, allowing you to fine-tune your settings for a more comfortable and personalized therapy experience.

APAP machines work both with you and for you. Life is full of changes and your sleep apnea therapy should adapt with you to each and every curveball.

Frequently Asked Questions About APAP Machines

What Does APAP Mean?

Automatic Positive Airway Pressure. The “A” in APAP may also be referred to as “Auto-Adjusting” or “Auto-Titrating” because it adapts automatically to your needs to deliver the lowest possible pressure for holding your airway open and keeping it free of obstruction. 

Is Auto CPAP the Same As CPAP?

Both machines use a stream of pressurized air to treat sleep apnea. A CPAP machine uses one predetermined pressure setting and will never deviate. APAP machines operate on a range and only deliver the least pressure necessary to hold the airway open, which is determined on a breath-by-breath basis. 

Is APAP More Expensive Than CPAP?

While the same brand and model of APAP will be more expensive than its identical CPAP counterpart, many APAP machines from other brands may be more affordable than CPAP machines from leading brands. APAP is not inherently more expensive in general. Travel machines are an affordable way to try APAP as they are typically auto-adjusting for convenience. 

Does an APAP Machine Stop Snoring?

An APAP machine will stop snoring in most cases, but it’s not uncommon for someone to still snore even with treatment. If you’re still snoring with APAP and use a nasal mask, your mouth might be falling open during the night, allowing pressure to escape without clearing your obstruction. You may also simply have a mask leak causing the issue.

Does APAP Help You Sleep?

APAP machines help people with Obstructive Sleep Apnea sleep better by holding the airway open and preventing apnea events that leave them waking up choking or gasping for air. By sleeping with an APAP machine, those with Obstructive Sleep Apnea are able to sleep through the night and wake up feeling energized and refreshed. 

The Bottom Line

APAPs have the same therapeutic goal as CPAP and BiPAP, but with a difference: they can automatically adjust air pressure to suit your changing needs as you sleep. This means you can begin therapy faster, make fewer trips to the doctor, and save on costs and time. Some CPAP wearers choose an APAP machine because they feel the variable air pressures make their treatment more comfortable and therefore, easier to use. Remember the number one goal is to treat your sleep apnea successfully and maintain compliance throughout your therapy journey.

We hope this helped you make a decision to choose the right machine that best fits your personal sleep needs. Leave a comment below and join our sleep apnea community at CPAPTalk.com to get answers from experienced sleep apnea wearers and experts.

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12 thoughts on “APAP vs. CPAP: What Is APAP and How Is It Different Than CPAP?”


    1. Thanks for the great questions, Elaine!

      This all depends on your preferred cleaning method. The Lumin CPAP cleaner is very convenient and operates differently than other cleaning products, using UV light to destroy 99% of bacteria, viruses, mold and fungi. Please call 1-800-356-5221 for assistance regarding payment options!


    1. Hi Allen,

      We advise all customers to use the machine type recommended by their doctor. That being said, it’s important to note the differences between an APAP or BiPAP and speak with your doctor about your personal sleep preferences.

      BiPAP machines provide two distinct pressures. The higher pressure is needed for inhalation, while the lower pressure in need for exhalation. The lower pressure is intended to help you breathe out against the pressure of the machine.

      Auto Adjusting CPAP machines, or APAPs, adjust to your ideal pressure on a breath by breath basis. They can accommodate pressure changes from weight gain or loss, alcohol before bed and changing sleeping positions during sleep.


  2. Can you provide links to medical studies that say APAP is better than CPAP. Many years ago my doctor told me CPAP was better. I realize technologies change and sometimes medical opinions change – trying to get the most updated information.

  3. I have a DreamStation Auto Cpap. I have a problem with the variation in sound when the machine is in the auto mode–my breathing tries to sync with the sound variation of the machine, so I now have it set on cpap. I would like to have it on auto..Any suggestions ?

    1. I have the same people with the dreamstation CPAP — I feel as though I have to match my breathing to the high and low pressure cycling but this leads to short and shallow breathing.

      I’d be interested to hear if anyone thinks that auto pap would be better, and if so, how do you find these settings on the machine?

      1. Hi Pattie, I am a fan of auto-titrating machines because the machine will give you the pressure that you need on a breath-by-breath basis. This way, you are not receiving too little, or too much pressure. Please speak with your doctor about your interest in using your machine in auto-mode.

        If your machine has this feature and you would like to change the mode, we will be more than happy to assist you with the setting change. Please reach us at: 800-356-5221.

        Enjoy your day!

      2. Christopher Jung

        Every APAP I have used is basically an adjusting Bi-PaP. You set the min and Max pressure. Say 6 to 18. As you breath as long as everything is going good the pressure will stay low, one it determines a problem, even so slight you don’t notice, it increases pressure until the breathing is within normal or max pressure is hit.

        I had a Bi-PaP at 6 and 18. ( Wonder where those numbers from above were from?). With data from also my Max pressure used was usually under 9, occasionally if congested to 12-13.

        When I had Bi-PaP the high pressure was obviously much higher than I needed and I almost always woke up with a puffy feeling in face and eyes.

        With lower pressure I had less leakage, blowby ( nasal pillows) and issue with mouth leakage. Add to this I was able to just remove the humidifier. Didn’t need it with APAP. ( Because of APAP or just used to it, I don’t know). Been using a system one from Phillips for about 7 years.

        But research paper, bring info to your doctor (he may not know much about them, mine didn’t) and see if he thinks they are right for you. Best thing is, most if not all APAP will let you disable the auto and run as a standard Bi-PaP and if you have min and Max pressures set to Sam, as a CPAP.

        Hope this helps. I am not a pap expert but 7 years using and stayed at a holiday inn Express.

  4. I use a Dream Station Auto SV.
    As you are aware, there are horrendous, widespread forest fires blanketing the NorthWest where i live right now. I keep all the house windows closed but it is impossible to keep the smoky odor out of my house. Consequently, the SV intake collects what smoky odor there is under my bed and “supercharges” it into my lungs. I wake often and have a sore throat from the smoke. Additionally, I meticulously clean what I can of the machine but there’s no way to clean the inside of the machine where smoke particles seem to be lingering… so two questions:
    1 Is it alright to run the machine for several hours without any accessories attached to try to purge the smoky odor from inside, and
    2 is there any kind of remote ‘super’ filter that can be attached outside of the machine to trap really offensive odors (whenever a skunk goes off outside the machine gathers his stink and it’s like he’s sitting on my chest!)?

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