We’re here to help! Call 1.800.356.5221
M-F 8AM-8PM | Sa 8AM-5PM (CST)

CPAP Pressure Setting 101: CPAP vs APAP vs BiPAP

Table of Contents

cpap pressure settingEverybody is unique, and every person with sleep apnea experiences it in a slightly different way. Because of this, sleep apnea therapy is not a one-size-fits-all treatment. Sleep apnea machines come equipped with settings that sleep specialists can change to fit each person’s unique needs and sleep apnea therapy experience.

A CPAP wearer can go years without really understanding much about their machine’s pressure and settings—and that’s understandable as long as it keeps working for them. However, if anything ever happens with your therapy or something changes with your health, understanding your CPAP pressure settings could help you and your doctor identify and solve any issues you may be having with your equipment.

How much do you know about your machine’s pressure settings, regarding how they impact your sleep apnea treatment? What’s the average CPAP pressure setting? What pressure setting should you be using? What should you do if you snore while using your CPAP machine? 

Let’s dive in!

Information About Your Pressure Settings

In general, your CPAP pressure setting should be just high enough to keep your airway open. When your pressure is too low, you may suffer from the symptoms of sleep apnea. If your pressure is too high, you may struggle to keep up with your therapy, have nasal congestion, and experience choppy or fragmented sleep. 

Your CPAP machine measures several things, including one key metric that sleep professionals use to determine the severity of your Obstructive Sleep Apnea (OSA). This is called the apnea-hypopnea index (AHI), and it indicates how many times you stop breathing over the course of an hour of sleep.

Your AHI number will help your doctor or sleep specialist determine the right pressure for you. In terms of AHI, the goal of CPAP therapy is to help you keep your AHI readings to five or less. To get there, a sleep study will help you monitor your number of AHI’s and determine if your OSA is mild (5 to 15 AHI), moderate (15 to 30 AHI), or severe (30 or more AHI).

The pressure of a CPAP machine is measured in centimeters of water (cmH2O)—a special unit of measurement that measures water pressure. This unit measures how much pressure a column of water exerts against its container. 

CPAP machines can be adjusted between 4 and 20 cmH2O. APAP machines also operate in that range, but since they are automatic, they are not set to a fixed number as a CPAP machine would be. Rather, they are capable of adjusting themselves within that range. BiPAP machines are slightly different as they can be adjusted to lower than 4 and higher than 20.

The average CPAP pressure is 10 cmH2O, and most people with sleep apnea require a CPAP pressure between 6 and 14 cmH2O.

APAP and BiPAP machines have some differences in terms of pressure settings when compared to a CPAP machine. Let’s explore the ins and outs of pressure settings with APAP and BiPAP machines.

APAP and Pressure Settings

Automatic positive airway pressure (APAP) machines automatically adjust themselves to your changing breathing patterns throughout the night. If you are like many people with sleep apnea, you tend to have more frequent bouts of paused breathing at some times of the night over other times. APAP automatically adjusts your air pressure settings to fit your changing breathing patterns.

Since it adjusts automatically, there is no average pressure—the machine uses sophisticated algorithms to ramp the pressure up or down based on the inhalations and exhalations of the wearer.

While 4 to 20 doesn’t sound like a big range of numbers, when it comes to determining your pressure, 16 is a significant distance from 10.

Your APAP machine is capable of adjusting itself within that 4 to 20 cmH2O range, so if your sleep apnea symptoms resurface while using an APAP machine odds are the culprit here is either a leaky mask, a change in your health, or something is wrong with the machine itself. Regardless of the potential source of the problem, if you begin experiencing your sleep apnea symptoms again while using an APAP machine, you should consult your specialist to narrow down possible causes.

BiPAP and Pressure Settings

A Bilevel Positive Airway Pressure (BiPAP) machine delivers two different air pressures to keep your airway open as you sleep. The machine senses when you inhale and exhale and produces different pressures accordingly. The BiPAP machine produces a high enough pressure to hold your airway open when you inhale and then produces a lower pressure when you exhale, making breathing easier.

Additionally, some people find it difficult to exhale over the constant pressure of the CPAP machine, which in turn, also complicates inhalation, making a BiPAP machine the best option for them. BiPAP machines are also adjustable to as low as 3 and above 20 cmH2O, unlike CPAP and APAP machines that are normally calibrated between 4 and 20 cmH2O. 

In most cases, if you use a BiPAP machine, there are also other special circumstances associated with why you are using BiPAP instead of CPAP or APAP. Your first line of defense to fixing the issue if you are experiencing sleep apnea symptoms again will be to examine your mask for any leaks or begin utilizing a humidifier. 

Is It Time for an Adjustment?

Your CPAP, APAP, or BiPAP pressure needs may change over time. But, how would you know? You may notice the return of snoring, gasping, or choking for air in the middle of the night or that you’re experiencing daytime sleepiness again.

These could all be signs that you are due for a pressure adjustment—or you may find that the answer is as simple as the fact that your mask is leaky. Before discussing a pressure adjustment with your doctor, you should try one of these things at home first:

  • Leaky Masks. There are a number of factors as to why your CPAP mask is leaking. These can include your mask being old, not being cleaned enough, your sleeping position, or the fit. High pressure can also cause your mask to leak, especially if it’s not sealed to your face properly.
  • Painful Gas or Bloating. Painful gas and bloating is a side effect of a CPAP machine, known as aerophagia. Aerophagia is a condition in which you swallow air during a night of therapy, causing uncomfortable bloating and gas when you wake up in the morning. You can fix it by first trying a different style of mask, but if that’s still a problem, a pressure adjustment or BiPAP machine may be what you need.

Snoring should not occur if your pressure is adequate, and your mask fit is correct. Remember that only trained professionals should adjust your machine’s pressure—regardless if it’s a CPAP, APAP, or BiPAP. 

While we hope to relieve some pressure (no pun intended) for you in understanding your PAP pressure settings, remember to contact your sleep specialist first if you have any questions about your pressure settings.

  • David Repasky

    David Repasky has been using CPAP treatment since 2017 and has first-hand experience with what it's like to live with Sleep Apnea. He brings the patient's perspective to the CPAP.com blog and has received formal training in CPAP machines, masks, and equipment.

Need Help With Sleep Apnea?

Table of Contents

58 Responses

  1. Hmmmmmmmmm – – – keeps talking about one’s specialist. What does one do when their apnea specialist is a turkey?

      1. Well thing is, as of the moment here in our place, other than general practitioners, it’s really very difficult to get in touch with sleep Doctors or go to sleep centers because of this pandemic. In our case here we nee to travel to another province and the hassles of the quarantines and series of swab tests just to go there. We have no choice but to really figure out our settings ourselves here

  2. If your machine is linked via a modem to the supplier like mine is they know the settings at all times I monitored. That is a same way to know you are doing ok pressure wise an equipment. I have Respirionics Equipment.

  3. on bipap machine resently went for overnight test and given printouts
    where do i find the measurements for high and low numbers

  4. My old CPAP unit was stolen a week ago. It is difficult to get to a specialist in some countries (I live in Mexico). I’ve been searching online for a new CPAP machine but I can’t find anything related to pressure settings when I read the descriptions for the machines. Can I just buy any of them and adjust the pressure all by myself? Is any software needed to do that or the new machines have a way for the user to change the settings?

    1. When you buy a new CPAP machine, you will need to have a prescription on file, and that prescription will have your pressure setting on it. We will set the pressure before sending it to you. If you need help tracking down the old prescription you can reach out to us at our number for international customers: +1 713-351-3414. Perhaps we can help you work out a solution to your problem that will get you back into CPAP therapy.

  5. I am from India Tamil nadu I have been using CPAP machine but my nasal Mask and head gear has got lost stipness , the agency I bought is not getting it for me. Where else can I get it.

    1. Hi Thomas,

      Some manufacturers of CPAP equipment prohibit sales to countries other than the US, so keep that in mind as you look for replacements. I think your best bet is to give CPAP.com a call at our international number of +1 713-351-3414. Keep in mind our CPAP experts are in the Central US time zone. When it’s 8 AM for CPAP.com, it’s 6:30 PM in India. Our CPAP experts can help you get the replacements you need. They’re friendly and knowledgeable.

  6. I have trouble with mask leakage. If I adjustthe headstraps to stop air leakage I have to cinch it up until it hurts. I get new masks every 3 months. I mask usually last a month. This is very uncomfortable and makes me not to use my BIPAP but I have frequent long period of not breathing without my BIPAP.
    Thank you for helping

    1. You might want to consider using a mask liner, as an inexpensive way to reduce the amount of leakage from your mask. Mask liners are great at improving the seal and making the mask more comfortable too.

  7. I asked my supplier to increase my pressure a bit as I don’t seem to be getting enough air. They only turned off the pressure delay but until I take off the nose piece, it feels as though I have to pull with my diaphragm in order to feel there’s enough air coming in. When I open my mouth, there’s lots of air that escapes under pressure. I tried using a Breath Right and it helped a bit but it’s uncomfortable and expensive over the long term. Any thoughts?

    1. SleepRight — little rubber doodads that go in your nose. Way better and cheaper than breath-rite strips. I wear them each night. Replace them in the package and they will last much longer than the 15 days cited.

  8. Some machines have optional exhalation relief. The machine automatically senses when the user is exhaling and reduces the pressure. For example DeVilbiss calls this feature smartflex. Do you know what the difference is between Smartflex and a Bi-pap machine?

    1. So a BiPAP machine is going to deliver therapy air at two distinctly different pressures, and can also be used to treat Central Sleep Apnea. SmartFlex is exhalation relief (and many modern machines have it). Exhalation relief makes it easier to exhale, but it’s not a BiPAP machine. If your doctor wants you to get a BiPAP machine, there’s no other device that can substitute for one.

  9. I have a Resmed AirSense 10 autoset cpap machine. This machine automatically adjusts pressure in real time as your pressure needs change. So, with that said, why would I need a Dr. to “prescribe” a setting if the machine automatically adjusts? Can’t I just set it to the “average” setting of 10 and let the machine adjust as need be?

    1. Hey Dave! Yes, you can. However, the machine would have to be set to a high and a low pressure. For example, if you know that you need at least a 10 pressure, but don’t need your pressure to go over 15, your pressure would be set to 10-15. If your doctor has no idea what your pressure is, you also have the option to have your pressure set at the default settings which is a minimum pressure of 4 and a maximum pressure of 20. Since it is an auto-titrating machine, you should only receive the amount of pressure you need on a breath by breath basis.

      I hope this information helps.

      Enjoy your day!

        1. Hi Artour, you can change your pressure setting, with your doctor’s approval. If you’ve spoken with your doctor and have a new pressure setting, we would be happy to assist you over the phone with the change.

          Please give us a call at: 1-800-356-5221.

          Have a great day!

          Best Wishes!

  10. My doctor gave me a pressure of 4. I had to buy the CPAP out of my own pocket and pay cash, because it was a percentage point above where Medicare would pay for it. My doctor has his own sleep study center set up in his own office. My doctor also said he would do a stem cell treatment for $1000 below another well experienced physician. My doctor had only done 10. I say this because it was obvious that my doctor was seriously worried about not making it financially. My doctor quit earlier this year by way of an email. He went to work for the VA. Do you think I need a CPAP machine?

    1. Hi Sharon, I am not medically able to determine if you need a CPAP Machine, or not. If you would like a second opinion, you may want to have another sleep study with a different doctor, or at least speak with a Sleep Specialist to confirm if you need a CPAP Machine.

      Please feel free to reach us with further questions, or concerns at: 1-800-356-5221, or via e-mail at: cpap@cpap.com.

      Have a great day!

  11. I’ve had my cpap for 7 months. Recently I’ve had trouble with a constantly runny nose (all clear liquid), sneezing & stuffy head. Is this common?

    1. Hey Sharln, I am sorry to hear that you are having some problems with your CPAP Therapy. It is not uncommon for you to have a runny nose, or the other symptoms that you mentioned. The symptoms could be unrelated to the CPAP Therapy, so please be sure to speak with your doctor. If you are not using a heated humidifier with your CPAP Therapy, you may benefit from adding one. If you are currently using a heated humidifier, you may try increasing the temperature just a little bit to see if this will provide some relief to you.

      For further questions, or concerns please feel free to reach us at: 1-800-356-5221, or email: cpap@cpap.com.

      We wish you the best!

    1. Hello, I have been unable to locate any information to support any claim that CPAP Therapy causes changes to the nostrils, or the shape of the nose. I would encourage you to direct your question to either your sleep clinic, or your doctor.

      Please feel free to contact us at: 1-800-356-5221, or email us at: cpap@cpap.com with further questions, or concerns.

      Enjoy your day!

  12. Can someone help please.
    My air pressure has gone up in the last week from an average of 10-11 to 14. I’m waking up it sounds like I have leak but my machine is telling me i have an 100% mask fit???

    1. Hi Dennis, how long has it been since you changed your cushion? If it has been more than 3 months, you may try changing your cushion, or if it has been longer than 6 months, you should change out your entire mask. Also, I would encourage you to make sure your hose is not leaking. You can do a test on your hose by removing your mask from the hose and covering the end of the hose with your hand while the machine is on to see if you hear the leak. If not, this will mean the leak is with your mask. However, if you hear the leak with the mask off, please replace your hose.

      If you are not able to pinpoint where the leak noise is coming from, please feel free to reach us at: 1-800-356-5221 and we will be more than happy to assist you via phone.

      We wish you the best!

  13. My original prescription was set at CPAP 14. After a few years and due to a change in machine to an auto device the prescription settings were altered to A Flex minimum 10 maximum 15. I now have been offered a new Auto machine with full setup manual. Is there any reason why I couldn’t set this up myself to my current setting?

    1. Hi Joe, as long as you have access to the Clinical Settings, you should not have any issues with setting the machine to match your current prescription. We do suggest you speaking with your doctor before changing any of your settings.

      If you have questions, or need assistance with setting your machine, please feel free to reach us at: 1-800-356-5221, or you may e-mail: cpap@cpap.com.

      Enjoy your day!

    1. Hi Ann, I am sorry to hear that you are having some issues with congestion and stuffy nose. Please see the link below to get better insight of your congestion and stuffy nose with suggestions on ways to decrease the symptoms. Also, we will be more than happy to confirm what the dial on your machine is for, but we must know the name of your machine.

      Please feel free to reach us at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.


      We wish you the best!

  14. Hello. I use an auto cpap machine settings 4-20 with a full face mask. Is it normal to feel air coming out from where the hose connects to the mask. And what does it mean if my pressure stays at 18-20 when I wake up in the morning

    1. Hi Angela, which mask are you currently using? Each mask has exhalation ports and it is very normal for air to come from the mask, but in order for me to confirm where it should be coming from, I must know the name of the mask. Also, it could be that you are experiencing a mask leak. Have you changed your mask cushion within the last 3 months, your entire mask within the last 6 months, or your hose within the last 6-12 months? I would recommend you confirm that you do not have a leak from your hose also. You can check this by turning your machine on and running your hand up and down the hose to see if air is seeping from it.

      What pressure setting is your machine set to? If it remains at a setting of 18-20, it could be the setting that your machine is listed at, or again, you may have a leak which will cause the machine to blow more pressure to compensate for the leak.

      We would be more than happy to go through some troubleshooting steps with you over the phone. If you are interested, please reach us at: 1-800-356-5221.

      We wish you the best!

  15. I have been using a CPAP since 2009. I recently had to do another sleep test and my settings have got to go from a 6 to a 9. I use a Phillip Resporonic machine. The Dr is writing order for new machine with increased settings. Where it is set on 6 inside my nose stays very dry and my mouth and throat are very dry and scratchy when I wake up and have a very dry cough. Could this be coming from because setting is to low at 6. Plus it has humidifier on it one day I may use all the water next day it won’t look like it’s used any water. Could something be wrong with machine cause they tell meu Medicare won’t pay for one but every ,5 years.

    1. Hi Mildred, i’m sorry to hear about the dryness that you have been experiencing. More than likely, the pressure setting has nothing to do with the dryness that you are experiencing.

      There is an explanation, as to why some nights, you may empty your water chamber and others, it’s as if you haven’t used the humidifier. It’s possible that your Phillips Respironics machine, may be using an ambient temperature. When the humidifier automatically adjusts to moisture in the room, it will not provide more moisture from the unit. (Some regions have a drier/humid climate, which can factor into this)

      You can go to your comfort settings and change from auto to manual. If you would like assistance with the setting adjustment, please feel free to contact our customer service department at 1-800-356-5221.

      Please see the link below of a moisture cream, that may provide you some relief as well.


      Also, keep in mind that waking with a really dry mouth/throat, is an indication that your mouth is falling open during the night. Are you currently using a full face mask? If not, I would recommend, you trying one to see if that helps.

      Please feel free to reach us for any further questions, or concerns.

      Have a great weekend!

  16. Lately I bought an APEX XT auto from CPAP .com invoice no M2609904.
    The past 18 days my AI is 0-1,HI is 6-13,SI is 4-12. My prescription was informed as 13cm H2O changed to 12 on my last CPAP and my AHI was less than 4.
    Now this new unit, the min pressure set is 4cm H2O while max is 20 set by CPAP.com.
    Please advice how to increase min pressure setting on this machine.

    1. Hi Willie, i’m not fully understanding your question. Are you trying to increase/decrease the pressure on your machine?

      If so, we always recommend that you speak with your doctor before you adjust your pressure. If you’ve already spoken with your doctor and it has been determined that your pressure needs adjusting and you have the correct pressure setting, please give us a call with your machine near you and we’ll be happy to assist you.

      We can be reached at: 1-800-356-5221.

      Have a great day!

  17. Does the pressure has anything to do for pain on lateral sides of the chest with swelling and pains in joints?

    1. Hi Pallav, my apologies for the delayed response. I am not able to confirm, or deny that the listed symptoms are causes from your CPAP therapy. If you are new to CPAP therapy, it could be your body adjusting to the air pressure.

      I would recommend you speaking with your doctor to confirm what may be causing you pain and swelling.

      For further questions, or concerns, please contact us at: 1-800-356-5221, you can ask for Carol, or e-mail us at: cpap@cpap.com.

      I wish you the best!

  18. I have an automatic machine. Why would therapist tell me that minimum setting for sleep apnea therapy is 8? Seems to me that arbitrarily overrides the automatic features provided by the manufacturer.

    1. Hi Caldwell, I would recommend you speak with your doctor, or therapist regarding your concerns. More than likely, your study results indicated your ideal starting pressure should not be less than 8. Keep in mind that every patient is different and whereas the minimum pressure on most machines is 4, not everyone can begin their treatment with such low pressure. Your settings are based upon your individual needs.

      For further questions, or concerns, we can be reached at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.

      We wish you the best!

    1. Hey Gerardo,
      The number of blowing hours, simply means the amount of time your machine as been turned on and blowing air. This doesn’t necessarily, mean you’ve used your machine for this amount of time.

      For further questions, or concerns, please feel free to reach us at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.

      Have a great day!

  19. Hi, I have lost 45 kilo in weight and when I have acquired a cpap machine and did a sleep test, it was set at 8 and because of my weight loss should it be calibrated lower or higher. I have been waking up with a very very dry mouth and a headache and all the water has been used in the machine and is very hot on the bowl. what do you think i should do ??

    1. Hi Robert, Congrats on your weight loss! After a significant weight change, there is a possibility you need a pressure adjustment. However, your doctor, or sleep specialist would have to make that determination.

      Your doctor may require you to have a new sleep test, or they may be able to review your complete therapy data to make a medical decision on any adjustments to your settings.

      Also, the dry mouth you’re experiencing could be for multiple reasons. Please check your therapy data to see if you have a high leak rate (usually over 24L/m), if so, or if you haven’t changed your mask cushion within the last 3 months, please do so. The complete mask with headgear should be changed every 6 months.

      Please consult with your doctor about the headache your experiencing, as this could be related to your pressure setting, or it may be un-related to your CPAP therapy.

      For further questions, or concerns, please feel free to reach us at: 1-800-356-5221, or you may e-mail us at: cpap@cpap.com.

      Best Wishes!

  20. I feel as if my cpap machine pressures are being tampered with while I’m asleep. How can I be sure this is or not happening?

    1. Hey A,
      Are you using an APAP (auto titrating machine)? This is a machine that has a high and low pressure setting and the pressure changes on a breath to breath basis to the pressure you’re needing. If your machine is set this way it’s most likely not being tampered with and in fact the machine is functioning properly.

      If you have a CPAP (constant pressure setting), you could have a ramp set, epr set, mask leak, or possibly a different technical issue.

      The probability, that someone is actually tampering with your machine during your sleep is low, unless there is someone in the room with you, entering the clinical menu and making setting changes.

      I would recommend you giving us a call, so that we may speak with you to better understand what’s actually happening during your sleep.

      Please reach us at: 1-800-356-5221.

      We hope to hear from you soon!

Leave a Reply

Your email address will not be published. Required fields are marked *

Need Help? 


Need more help? Contact us!

Get help from an expert like Liz

Our experts know CPAP inside and out. Give us a call today and one of our 5 star customer service representatives will help you.

or Text "Help" to 832-308-2219

or Text "Help" to 832-408-9760

Mon-Fri 8am-8pm CST, Sat-Sun 8am-5pm CST