Can I get a grant if I'm just replacing the glass in my windows?
No, the grant is for the replacement of a full window unit (ENERGY STAR qualified) not just the glass. And remember, the grant is per “rough opening” meaning you receive $80 per opening, not window. That means that no matter how big or small the window, the grant is $80. If you are replacing a large picture window with two windows on the side, or if you are replacing your front door with the long windows on each side, that is considered one rough opening, not three windows or a door and two windows.
Remember to ask your window vendor if the windows you are purchasing are ENERGY STAR qualified for your climate zone, in order to qualify. You can find out more about ENERGY STAR here.