Adding square footage via unfinished room

[Derek Kreps]

I was wondering if anyone has any guidance on this and if it's as simple as I'm thinking. We've got a room in the back of our house that is unfinished and isn't currently counting towards our total sq footage. It used to be a garage (detached 2 car was added prior to when we bought), and is a mix of a shop room and a laundry room is connected. My thoughts, hire a contractor to connect the ductwork to get HVAC linked with this room which SHOULD mean we get to add this portion (approx 250 sq ft). Has anyone else done this before and from a flip perspective, how did that extra space impact your ultimate value? Home values are around $150/sq ft in our area, so this seems like a no brainer for a relatively simple and inexpensive project. Anything I'm not thinking of?