To be eligible for a FHA HECM, the FHA specifies that you just be a home-owner sixty-two years old or older, own your home outright, or have a low mortgage balance that may be paid off at closing with proceeds from the reverse loan, and you need to live within the house. You are also required to receive consumer  information from an approved HECM counselor prior to getting the loan.  

When you sell your home, you or your estate will repay the money you received from the reverse mortgage plus interest plus alternative fees, to the lender. The remaining equity in your home, if any, belongs to you or to your heirs. Discover more about HUD reverse mortgage here.

The amount you can borrow depends on your age, the present interest rate, and the appraised worth of your home or FHA's mortgage limits for your space, whichever is less. Typically, the more valuable your home is, the older you are, the lower the interest, the extra you are able borrow. You can use an online calculator such the one on the AARP web site to have an idea of what you'll be able to borrow.