This is a very rough idea.
Difficult to give you a dollar value... so many variables involved. Here in the Berkshires, where many of our buyers winter in Florida, central air is desirable and therefore has a premium. And a finished basement really depends on how it is finished, and what it used for. In general, finished basements add considerable value no matter what market.
Associate Broker, Massachusetts, New York, and Connecticut
Berkshire Property Agents
12 Railroad Street
Great Barrington, Massachusetts 01230
Also finished basements can vary greatly on the level of finish and quality.
You can from the home builders association get ranges of what improvements add to the value of a home in a area of the country, ie: Boston, Atlanta, San Jose, etc.