BACKGROUND: Positive airway pressure (PAP) is the accepted standard treatment for obstructive sleep apnea. In the last decades, automatic PAP (APAP) adjustment modes have been increasingly used. Pressure auto adjustment offers better comfort to the patient and represents a valuable help for the clinician to provide optimal treatment. However, device performance differs among manufacturers. Furthermore, the success of the therapy relies greatly on unintentional air leak level for many reasons, hence the importance to investigate the performance of the most common devices. The aim of this study was to compare the performance of 3 APAP devices from the most common manufacturers in specific conditions (ie, obstructive sleep apnea, central sleep apnea, hypopnea), with and without unintentional air leak. METHODS: This was a bench test study. Performance tests were conducted on a breathing simulator using a Starling resistor, representing the upper airways, and an adjustable unintentional air leak valve. Three APAP devices (AirSense 10, DreamStation, and Prisma 20A) were tested in different scenarios. RESULTS: Without unintentional air leak, performance of the 3 devices was similar to existing literature. However, performance was altered with the addition of unintentional air leak in some scenario. The AirSense 10 was not able to respond correctly to obstructive apnea (intraclass correlation coefficient [ICC] 0.021, P = .61) and hypopnea (ICC 0.059, P = .26). Prisma 20A lowest performance was seen during simulated obstructive apnea (ICC 0.708, P < .001). DreamStation lowest performance was seen during simulated hypopnea events (ICC 0.755, P < .001). CONCLUSIONS: All 3 APAP devices reacted differently to the added unintentional air leak. Performance was altered with some devices, which could affect the therapy success in patients with sleep apnea syndrome. The variability of performance of some APAP devices with unintentional air leak should make clinicians evaluate their use in a home setting.