There are many factors to consider when considering a garage conversion vs building a room addition. The simple answer is should be less expensive to convert your garage into an extra bedroom. Where is starts to get expensive is when start adding plumbing for a kitchen or bathroom, update electrical systems and add HVAC. Check with your local municipality to make sure that you are able to convert your garage without any city ordinances. Alamo Heights does allow garage conversions, but you are required to build a separate carport or garage if decide to convert your garage into living space. The City of Alamo Heights also doesn’t allow AIRBNB or VRBO, so be prepared to research that as well.