CPAP vs. APAP vs. BiPAP: which machine your prescription actually points to

Part of the series: The Complete CPAP Guide

One pressure, a pressure range, or two pressures. The three-letter alphabet decoded, and why you can't trade up the ladder on your own.

The alphabet is simpler than it looks: CPAP delivers one fixed pressure all night. APAP (auto-CPAP) adjusts within a prescribed range breath by breath, responding to flow limitation as it happens — we've written a full piece on that mechanism. BiPAP delivers two pressures, higher on inhale and lower on exhale, with the gap making breathing work easier. Each is a superset of the last in capability, and roughly in price: $599–$949 for CPAP/APAP in our catalog, $1,395 and up for bi-level.

Most new obstructive sleep apnea prescriptions today land on APAP, and for good reason: your pressure needs aren't constant — they shift with position, sleep stage, alcohol, congestion, and weight — and an auto machine tracks that instead of holding the worst-case number all night. Fixed CPAP still earns its keep when titration found one stable pressure that works, where its simplicity and lower price ($599 vs. $949 in our lineup) are genuine advantages.

BiPAP is not the luxury tier of CPAP — it's a different tool with its own indications: pressure needs too high to exhale against comfortably, certain hypoventilation patterns, and central or mixed apnea presentations, where adaptive servo-ventilation (a further specialization, $3,995) may enter the conversation. We've covered why central events change the machine question entirely in our central-vs-obstructive piece.

The practical point for a buyer: the machine class is the prescription's decision, not the cart's. You can't self-upgrade from CPAP to BiPAP any more than you can double a medication dose — the verification step will catch the mismatch, and that's it working as intended. What you do control is everything within the class: platform generation, travel form factor, and the mask, which affects nightly comfort more than any machine spec does.

This article is general health information, not medical advice, and doesn’t replace evaluation by your own physician. Talk to a doctor about anything specific to your own diagnosis or treatment.

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CPAP vs. APAP vs. BiPAP: which machine your prescription actually points to

Part of the series: The Complete CPAP Guide

One pressure, a pressure range, or two pressures. The three-letter alphabet decoded, and why you can't trade up the ladder on your own.

This article is general health information, not medical advice, and doesn’t replace evaluation by your own physician. Talk to a doctor about anything specific to your own diagnosis or treatment.