What is the best way to convert a garage to livable space?
An uninsulated space will be a huge energy waster. Expensive yes, you would need to have the walls insulated, the roof structure insulated and finished, as well as the door rollup door insulated. If you plan to never use it as a garage again, the door can be removed and a wall put in its place. Some people even build a portion of the garage into a shed in the front, to keep the door. Other things to consider are the floor, cold in winter, hot in summer. But there are lots of things that can be e done to convert a garage. Depends on how much money you want to spend, how much you want to convert, if you plan to ever use it as a garage again...