Quick answer
CPAP, APAP, travel CPAP and bilevel PAP are not interchangeable labels for the same machine. Fixed-pressure CPAP delivers one prescribed pressure, APAP adjusts within a prescribed range, travel CPAP prioritizes portability, and bilevel PAP provides different inhalation and exhalation pressures for specific clinical needs. Start with the prescribed therapy mode, then compare humidification, mask and accessory compatibility, data access, support and total ownership cost.
CPAP machine types compared
The clearest comparison separates therapy mode from size and convenience. “CPAP” is often used casually for every positive airway pressure device, but the prescribed mode and pressure pattern still matter.
Fixed-pressure CPAP
A fixed-pressure CPAP delivers the prescribed treatment pressure while the person is using it. Comfort features such as ramp or expiratory pressure relief may temporarily change how pressure feels, but they do not turn a fixed-pressure machine into APAP or bilevel therapy.
Fixed pressure can be predictable and effective when the setting is appropriate and tolerated. Read How CPAP Works for a plain-language explanation of the machine, circuit, mask and intentional exhalation vent.
Auto-adjusting PAP (APAP)
APAP uses a manufacturer-specific algorithm to adjust pressure within prescribed minimum and maximum limits. The device responds to breathing signals it detects; it does not independently diagnose every event or replace clinical review.
The lower and upper limits influence how the device can respond, so a wide range is not automatically better. Do not change prescribed limits based only on a nightly score. Review symptoms, leaks, usage and device data with the responsible sleep-care professional. The CPAP Pressure Settings guide explains ranges and common report fields.
APAP vs CPAP: which is better?
Neither is better for everyone. The American Academy of Sleep Medicine recommends either APAP or fixed CPAP for ongoing treatment of obstructive sleep apnea in adults, because studies found no meaningful difference in how much people use them, daytime sleepiness or quality of life (Patil et al., J Clin Sleep Med, 2019). APAP can be more comfortable when your pressure needs change with sleep position, alcohol or weight, while fixed CPAP is simple and predictable. Most home machines sold today can run in either mode, as your clinician prescribes.
Travel CPAP
Travel CPAP describes a smaller product format, not one unique therapy mode. Some travel machines provide fixed pressure, some provide APAP, and features may differ from a full-size bedside device.
Before relying on a travel machine, confirm:
Use the Travel With CPAP guide and browse our Travel CPAP collection when planning a portable setup.
- that its therapy mode and pressure settings match the prescription;
- whether it works with the intended mask, tubing and humidification approach;
- available power supplies, battery options and destination voltage;
- airline documentation and current carrier rules;
- noise specifications and how the device sounds with the complete circuit;
- access to reports, technical support and replacement supplies; and
- whether insurance or a public program treats a second or travel device differently.
Bilevel PAP
Bilevel PAP delivers a higher pressure during inhalation and a lower pressure during exhalation. Depending on the device and mode, it may also include additional timing or ventilatory-support functions. It is selected for specific clinical reasons and requires appropriate prescription, setup and follow-up.
Bilevel is not automatically more effective, more comfortable or more advanced for every person with obstructive sleep apnea. Someone struggling with CPAP should receive troubleshooting and clinical review rather than assuming that buying a bilevel device is the answer.
Comfort features are not therapy modes
Ramp, heated humidification, heated tubing and expiratory pressure relief can affect comfort, but they should not be confused with fixed CPAP, APAP or bilevel therapy. Feature names are manufacturer-specific, and similar names may not mean identical behaviour across brands.
A useful comparison asks two separate questions: does the device deliver the prescribed therapy, and does its comfort and support system make consistent use practical?
Compare the complete machine ecosystem
Once the therapy mode is confirmed, compare:
Do not assume that an application or cellular connection provides continuous clinical monitoring or emergency support. Confirm who reviews transmitted information, how often, what follow-up is included and what to do when help is needed.
- integrated or removable humidification and heated-tubing support;
- approved masks, standard or proprietary connections and accessory compatibility;
- display controls, data storage, SD-card access and remote-connectivity options;
- what data the user and care team can access and whether connectivity has ongoing requirements;
- published sound level, dimensions, weight and placement requirements;
- power supply, power consumption, battery compatibility and travel needs;
- filter type, cleaning instructions and availability of replacement components;
- Canadian medical-device licensing for the exact model where applicable;
- manufacturer and seller warranty terms, return conditions and authorized support; and
- expected costs for supplies and replacement parts over time.
A practical comparison checklist
The CPAP Buying Guide expands this checklist, while CPAP Machines Canada lists the machines we sell.
- Confirm the diagnosis, prescribed therapy mode and pressure or pressure range.
- Identify required comfort features, humidification and any relevant breathing or health considerations.
- Confirm compatibility with the intended mask, tubing, filters, water chamber and power accessories.
- Compare data access and clarify who reviews it, when and for what purpose.
- Verify the exact product identity, Canadian licensing where applicable, warranty and seller support.
- Calculate the total price, including required accessories, replacement supplies, delivery and taxes.
- Check prescription, insurer or public-program documentation before purchase without assuming reimbursement.
How we compare machines (and why no one machine is best)
Rankings that crown one “best CPAP machine” ignore the things that matter most: your prescription, your mask, where you sleep and how your care team monitors therapy. We compare the machines we sell on type, sound, weight, humidification, data, warranty and price in one table in our CPAP buying guide.