My condo does not have a basement. I have a subfloor with three dummy registers. I don't know why they are there. My heating ducts are in the upper part of the side walls. In the winter the cold radiates two feet above the floor making it uncomfortable to keep my feet off the couch.
I wanted to insulate the space under the subfloor through the dummy registers or from the garage inside wall.
Is this something I should look into? Would it work?