Medicare generally covers the rental cost of portable oxygen concentrators like Inogen units under Medicare Part B, typically paying around 80 percent of the Medicare-approved amount after the patient meets their annual Part B deductible. Patients are responsible for the remaining 20 percent coinsurance. Medicare usually structures this as a 36-month rental agreement, after which equipment maintenance and servicing rules apply, though Medicare typically does not cover the outright purchase price of portable oxygen concentrators.