Full enclosure: $20,000 or more. This is a totally built structure that may be attached to or detached from your home. Everything (foundation, walls, windows, doors, and roof) is built from the ground up. If you add it to your house, the contractor will make it match the rest of the house. Electrical, heating/cooling, and plumbing components may also be included.
The cost of a partial enclosure is between $5,000 and $10,000. This is commonly done when you leave portion of the patio space open to the elements. You may surround the space with simple screens, doors, windows, or a separate roof.
$15,000-$22,000 for a sunroom.
These are frequently pre-made modifications. Climate controls prevents it from becoming musty or moldy.
So many variables to choose from, for more information check out more patio covers here.