The key is for the space to become a value selling attribute... don't do it unless you want to do it right because you'll detract from your home's value if it ends up looking like a conversion job rather than the way the house was originally built. Is the floor lower than that of the rest of your house? You'll have to build the floor up to match unless it's so much lower that you can open up a nice wide doorway and put in decorative stairs so that it looks like an intentionally sunken space. Or, would raising the floor make the ceiling too low? You have to consider all these things before you start. You will have to take the garage door out and enclose the hole, so you'll have to get siding to match the rest of your house; you'll probably want to put in a nice big window there, too because most garages don't have any (you might want to consider adding a window on the side, too). You will need to put up drywall unless it's already there, and check to see if there is insulation in the walls which there probably isn't. You will need to insulate the walls and in the attic, and run ductwork out there for heating & air, making sure that your ac unit can handle the extra square footage. Another way to keep it from looking like a conversion job from the outside is to consider reshaping the driveway after you're done so that it doesn't look like it runs into the side of a finished house... a tale tell sign of a conversion that most people don't fix. Check with your city/county regarding permits required for this work, before you do anything at all. My advice? If you need extra space, it's not worth taking out a garage that some buyers would consider a required necessity unless you plan to add some other kind of covered or enclosed parking solution. Chances are you will probably look to sell your house at some point so you need to consider that heavily. You might be better off, depending on the market in your area, just buying a new house.