If you’ve been diagnosed with sleep apnea, you might feel overwhelmed trying to understand your sleep apnea treatment options. These days, there are a lot of solutions available, but APAP and CPAP therapy devices are the two most common.
Both machines are designed to help you breathe better at night, but how do you know which one is best for you? Today, we’ll compare APAP versus CPAP in simple terms, so you can better understand what they are, how they work, and which one is right for you.
Table of contents
Comparing APAP versus CPAP
Both devices fall into a category of non-invasive breathing support called "positive airway pressure therapy". This is where the "PAP" in "CPAP" and "APAP" comes from.
All PAP machines work by gently delivering pressurized air through a mask to keep your airway open during sleep, preventing pauses in breathing (apneas) and improving sleep quality.
The difference lies in how each device delivers pressurized air to your airway:
- CPAP (Continuous Positive Airway Pressure): Delivers one constant pressure all night long.
- APAP (Auto-Adjusting Positive Airway Pressure): Automatically adjusts air pressure when it senses changes in your airway and sleep apnea events.
APAP Machines
- PAP Type: Automatic Positive Airway Pressure
- Other Names: Auto CPAP, AutoPAP, Auto-adjusting, AutoSet™
- Used to Treat: Obstructive sleep apnea, upper airway resistance
- Pressure Delivery: Automatically adjusts to changes in snoring and apneas
- Good For: People with OSA whose pressure needs change frequently, those who are new to or adjusting to sleep apnea therapy
- Considerations: Costs more than a fixed CPAP, not suggested for central sleep apnea or frequent air leaks
CPAP Machines
- PAP Type: Continuous Positive Airway Pressure
- Other Names: Fixed-pressure CPAP, single-pressure CPAP, traditional CPAP
- Used to Treat: Obstructive sleep apnea, central sleep apnea, upper airway resistance
- Pressure Delivery: Delivers one consistent pressure level all night
- Good For: People whose sleep apnea is well controlled at one pressure setting, those with frequent air leaks, and some people with central sleep apnea
- Considerations: Less comfortable than APAP, no way to adjust pressure if therapy needs suddenly change
| CPAP | APAP | |
|---|---|---|
| Pressure Adjustments | Fixed | Automatic |
| Pressure Settings | One, doctor-prescribed | Range, doctor-prescribed |
| Pressure Limits | 4–20 cm H2O | 4–20 cm H2O |
| Conditions | Obstructive, central sleep apnea, upper airway resistance | Obstructive sleep apnea, upper airway resistance |
| Stimulates Breathing | No | No |
| Machine Cost | ~$500–$900 | ~$700–$1,100 |
| Portability | Limited travel machines | Several travel machines |
| Insurance Coverage | Covered | Covered |
| Sensors | Basic flow | Flow, snoring |
| Comfort Features | Heated humidity, ramp, expiratory pressure relief | Heated humidity, ramp, expiratory pressure relief, auto-adapting pressure |
What is an APAP machine?
APAP (sometimes called Auto CPAP) stands for automatic positive airway pressure. Just like a regular CPAP, APAP machines release a steady stream of pressurized air to keep your airway open as you breathe in and out, but what makes an APAP special is that it can adjust its pressure setting on its own.
These devices ensure you get just the right amount of support as your airway changes depending on your sleep stage and body position. To do this, they use sensors to monitor how your airway changes between each breath, then adjust your APAP pressure as needed.
✓ Pros
- Adjusts to your needs in real-time
- More comfortable for many users
- Fewer doctor’s visits to adjust settings
- Lower average PAP pressure over time
- Easy to use
- Built-in cushion for weight change or sinus congestion
- More people stick with it long-term
- Several travel-friendly devices
- Compatible with all masks
✗ Cons
- More expensive than CPAP
- Pressure changes may disrupt light sleepers
- More complex technology
- Cannot adapt to central sleep apnea events
- Pressure usually limited to 20 cm H₂O
- Sensors may require extra maintenance on rare occasions
How does APAP pressure work?
APAP machines automatically adjust the pressure to prevent airway blockages
Your sleep doctor will look at your sleep test or CPAP titration results to figure out the best pressure range for your airway needs. Then, a technician will program your APAP machine to stay within that prescribed range.
Once you start therapy, your APAP will use sensors to identify changes to your snoring or apnea episodes. Then it will adjust your therapy pressure to the lowest amount needed to keep your airway open, within the range prescribed by your doctor.
APAP sensors are primarily designed to respond to OSA events and prevent airway blockages. They struggle to prevent central sleep apnea events and can become confused by frequent air leaks.
Are auto CPAP machines worth the cost?
APAP devices cost more than a traditional fixed CPAP, but they are also more readily available and give you more bang for your buck. Auto CPAPs are often designed with multiple therapy modes, including auto and fixed CPAP. This means that if your therapy needs change over time, you may be able to simply switch therapy modes, rather than buy a whole new machine.
Is auto CPAP right for you?
APAP devices work well for most people with OSA but they aren't for everyone
Auto CPAP machines have become very popular for treating most people with obstructive sleep apnea because they offer flexibility and comfort, and are suitable for a wide range of people.
But APAP isn’t perfect for everyone. If your mask leaks a lot or you have central or complex sleep apnea, the machine may have trouble giving you the full support that you need to maintain a healthy breathing pattern.
APAP therapy may work for you if…
Your airway changes overnight. Your airway blockages are less frequent early on in the night but you need higher pressure therapy during deep sleep or while resting in certain sleeping positions.
Your sleep apnea severity changes over time. Your sleep apnea severity will probably change over months or years due to health, body weight, or lifestyle changes, meaning your pressure needs may also change.
Your sinuses are frequently congested. You experience nasal congestion on a regular basis, which makes your sleep apnea worse.
You’re new to sleep apnea PAP therapy. You’re a CPAP beginner and need help adjusting to using a sleep therapy device.
You’ve struggled to adapt to CPAP. You’ve tried CPAP and just could not get used to the feeling of air constantly flowing into your face.
APAP therapy may not work for you if...
You have central sleep apnea. If central apneas make up a significant portion of your recorded sleep apnea events, an auto-adjusting algorithm may not be able to encourage a normal breathing pattern.
You're a very light sleeper. APAP pressure changes may cause you to wake up if you're a light sleeper who is easily disturbed by changes in your sleeping environment.
You experience frequent air leaks. When your mask leaks air, it can confuse an APAP machine’s sensors and logic, leading to erratic or overly high pressure levels.
You need ventilation support, not just an open airway. Certain people with conditions like COPD or neurological disorders require more respiratory support, such as backup breaths, which isn't available on an APAP machine.
Examples of popular APAP machines
What is a CPAP machine?
A CPAP, or fixed-pressure CPAP, stands for continuous positive airway pressure. These machines deliver a constant, steady stream of pressurized air through a mask to keep your airway open while you sleep.
That single pressure setting is chosen ahead of time during a sleep study or titration trial and stays the same no matter your sleep stage or body position. Because the technology is a bit more basic, CPAP devices are a simple, cost-effective treatment for sleep apnea.
Like other Positive Airway Pressure devices, a CPAP machine directs a steady stream of pressurized air through the nose or mouth and into the airway. But unlike other PAP machines, this pressure level is determined by your . This pressure setting is constant and shouldn’t be changed without first consulting your healthcare provider.
✓ Pros
- Simple, easy to use designs
- More budget-friendly options
- Proven effective sleep apnea treatment
- Quick and simple set-up
- Provides stable support for some cases of central sleep apnea
- No unnecessary pressure changes if your mask leaks air
- Steady airflow is less likely to cause sleep disruptions
- Fixed pressure setting available on most APAP devices
- Makes it easier to troubleshoot lingering sleep apnea events
✗ Cons
- Fixed pressure may feel uncomfortable
- Pressure may be too high on good nights
- Pressure can’t increase on bad nights
- Can be more difficult to adjust to
- Does not adapt as your sleep apnea needs change
- Standalone CPAPs are less readily available
How does fixed CPAP pressure work?
CPAP machines maintain a steady, single-pressure setting
After reviewing your sleep study, your doctor chooses one therapeutic pressure, the lowest setting that will keep your airway open through all sleep stages. A technician then programs your CPAP machine to deliver that exact amount of pressure all night long.
Once your CPAP machine reaches its prescribed pressure it holds that level for the entire night, regardless of your sleeping position or sleep stage. Comfort features like exhalation relief can briefly dial the pressure down by a couple of levels while you breathe out, but the baseline pressure never changes on its own.
Are fixed-pressure CPAP machines worth the cost?
While CPAP machines are the most budget-friendly of all the PAP devices, they have become less popular in recent years and may be harder to find. APAP devices usually include both auto and fixed pressure modes. So many people end up paying for the more expensive APAP, giving them the flexibility for an automatic or fixed pressure sleep therapy.
Is single-pressure CPAP is right for you?
CPAP devices work well for sleep apnea that is well controlled at one pressure setting
Single-pressure CPAP therapy may be less comfortable to sleep with compared to auto CPAP, but there are some people who do thrive with fixed CPAP.
These CPAP machines are ideal for people whose airway needs stay consistent throughout the night. The steady airflow and fewer sensors mean fewer tech issues, an easier learning curve, and effective results.
But if your pressure needs change once you hit REM sleep or decrease when you roll onto your side, you may need something that can automatically adapt to those changes.
CPAP therapy may work for you if…
Your obstructive sleep apnea is controlled with one pressure setting. You only need one pressure setting to keep your airway open in every body position and sleep stage.
You're therapy pressure is very low. Your prescribed pressure setting is so low that APAP adjustments aren’t noticeable enough to make you more comfortable.
Your central sleep apnea is responsive to a single pressure CPAP. Fixed CPAP supports the respiratory system with a steady flow of air, which in some cases is enough to settle central sleep apneas and encourage normal breathing.
You need a lower-cost sleep apnea solution. You are looking to save some money on your CPAP equipment and are confident you can stick with a fixed-pressure CPAP machine long-term.
You experience frequent air leaks. Large air leaks can trick an APAP machine into thinking you are experiencing a sleep apnea episode, which can lead to your pressure being increased higher than you actually need it to be.
CPAP therapy may not work for you if...
Your sleep apnea is better controlled by BiPAP or ASV. Some cases of central sleep apnea require more respiratory support than CPAP therapy can provide.
Your pressure needs swing a lot from night to night. A single fixed setting can be too low during REM sleep or when you roll onto your back, while also being too high on good nights.
You struggle to rest comfortably with fixed-pressure CPAP. If a constant, unchanging blast of air leaves you feeling overwhelmed, dry-mouthed, or unable to relax, a fixed-pressure CPAP may be harder to tolerate than an auto-adjusting APAP.
You need ventilation and airway support. Conditions like COPD or certain neuromuscular disorders call for pressure-support boost or backup breaths, which aren't available on a standard CPAP machine.
Examples of popular fixed-pressure CPAP machines
Is APAP better than CPAP for sleep apnea treatment?
APAP is generally the best first-line option for OSA, especially for comfort, convenience, and long-term success. But CPAP still has its place, especially for those with steady needs, budget concerns, or specific medical situations.
If you’re unsure which one’s right for you, talk to your doctor. You may even be able to get a machine with both APAP and CPAP modes, so you have options as your needs evolve.
Frequently asked questions
Do insurance companies cover APAP machines?
Back when APAP therapy was a newer technology, health insurance companies had stricter requirements you had to meet before they would cover an APAP machine. But these days, most insurance policies cover standard-sized CPAP and APAP machines. You should always check with your insurance provider to be sure. Machines that are often covered by insurance include the AirSense 10 and AirSense 11 AutoSet CPAP devices by Resmed.
Are APAP machines more expensive than CPAP machines?
APAP machines are usually more expensive compared to a fixed pressure CPAP. APAP machines typically range between $900 to $1,100, while CPAP machines cost anywhere from $700 to $900.
Are APAP machines effective for treating sleep apnea?
Auto CPAPs are highly effective for sleep apnea. Thanks to their automatic adjusting capabilities, these machines are able to change the exact amount of pressure that you need at any given moment, especially as your sleep stages change, you shift body positions, or when you're experiencing airway inflammation.
What are the difference between auto CPAP and fixed pressure CPAP?
Auto CPAP (also called APAP) automatically adjusts pressure on a breath-by-breath basis, depending on how your airway changes throughout the night. Fixed-pressure CPAP delivers one constant pressure level all night long. Auto CPAP offers more flexibility, better comfort, and fewer CPAP side effects, especially if your pressure needs vary during sleep.
What are the similarities between auto CPAP versus fixed CPAP?
Auto and fixed-pressure CPAP machines ultimately prevent obstructive sleep apnea events by delivering a flow of positive air pressure to the airway, which acts as a brace to hold the airway open as you sleep. They also offer many of the same comfort features. Plus, the process for getting a prescription for both machines is the same. Your doctor will choose which one is right for you once they review the results of your sleep apnea test.
What is AutoSet versus CPAP mode?
AutoSet is the term that one popular APAP manufacturer, ResMed, uses to refer to their version of Auto CPAP. However, ResMed APAP machines also feature something called CPAP Mode, which effectively turns off the AutoSet feature and allows the machine to double as a traditional fixed-pressure CPAP machine.
Do APAP machines need to be replaced more often than a CPAP machine?
Usually, a standard-sized APAP machine will need to be replaced about as often as a standard-sized CPAP machine, which is about every 5 years. The replacement schedule for your machine parts will also be similar, regardless of whether you use an APAP or a CPAP.
Do I need a special mask for an APAP machine?
You do not need a specific type of mask to use your APAP machine. While you can wear a CPAP mask during APAP therapy, keep in mind that not all CPAP masks are designed to meet your needs. For example, if you are someone who requires highly pressurized airflow, you may want to avoid a nasal pillow mask. And if you tend to feel claustrophobic, a full face mask may be very uncomfortable for you.
Can I travel with my APAP machine?
Standard-sized APAP machines offer the same level of portability as a standard-sized CPAP machine, meaning they are FAA and TSA approved. But if you're a frequent traveler, it may be more convenient to purchase a travel machine. Some of the best machines for CPAP travelers are APAP machines that offer the option between auto and fixed-pressure CPAP therapy, such as the Transcend Micro.
What's the difference between APAP and BiPAP?
The difference between APAP versus BiPAP is how and when they deliver air pressure.
BiPAP machines use two prescribed pressure levels—one higher pressure for when you breathe in and a lower one for when you breathe out. Some BiPAP models are also auto-adjusting and can even trigger a breath if your breathing slows or stops for too long.
APAP machines produce one continuous flow of air pressure, which is adjusted as your airway needs change throughout the night. But the pressure stays the same for both inhaling and exhaling. These Auto CPAP machines are also not designed to trigger breathing.
BiPAP has been used to treat people with more complex respiratory conditions, such as COPD, hypoventilation, certain neuromuscular disorders, and cases of sleep apnea that are resistant to CPAP therapy. While APAP is really only used for obstructive sleep apnea and upper airway resistance.
Is auto continuous positive airway pressure (Auto CPAP) the same thing as APAP?
Yes. In fact, APAP technology goes by several different names. Here are some other terms that are used in place of "APAP":
- Auto CPAP
- Auto-Adjusting CPAP
- Auto-Titrating CPAP
- Self-Adjusting CPAP
- Auto PAP
- Automatic CPAP
- AutoSet
- SmartPAP
What are the types of positive airway pressure (PAP) devices?
There are four main types of Positive Airway Pressure machines, which vary from most to least technologically involved. Your most common options for PAP therapy include the following:
- Continuous positive airway pressure (CPAP)
- Bi-level positive airway pressure (BiPAP)
- Auto-adjusting positive airway pressure (APAP)
- Adaptive servo ventilation (ASV)
Does APAP treat obstructive sleep apnea?
APAP is a great option for treating Obstructive Sleep Apnea. In some people, OSA gets more severe as they fall deeper asleep. Others experience worsening airway obstructions depending on the position they are lying in. In these cases, it is very helpful to have the option of having your air pressure increased during those periods but then decreased for those times when your OSA is less severe.
Final thoughts
When it comes to choosing between APAP versus CPAP, finding the right sleep therapy device comes down to how much flexibility and support you need.
If your pressure needs change from night to night, an auto-adjusting APAP usually offers the easiest, most comfortable path to steady sleep. But if one set pressure keeps your airway open, and you prefer a simpler, lower-cost setup, a fixed-pressure CPAP can still deliver great results.
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