You pay 20% of the Medicare-approved amount for rental of the machine and purchase of related supplies (like masks and tubing), and the Part B deductible applies. Medicare pays the supplier to rent the machine for 13 months if you’ve been using it without interruption. After you’ve rented the machine for 13 months, you own it.
Note: If you had a CPAP machine before you got Medicare, Medicare may cover rental or a replacement CPAP machine and/or CPAP accessories if you meet certain requirements.
If you live in certain areas of the country, you may have to use specific suppliers for Medicare to pay for a CPAP machine and/or accessories.
Source: Medicare & You 2017