Stair Lift for Grandmother's House

My uncle is looking for a stair lift to fix on my grandmother’s double storey house back in home town. My grandmother can still walk but it will take her a long time to climb up the staircase and it is no longer an easy task for her especially with her joint pain on her knees. We hope that with the stair lift, this will ease grandmother’s movement from downstairs to upstairs vice versa.