I have a sewing room that's 10x14' w/a bay window & I get the sun on it most of the day. I shut off the heat vent, installed a short bladed ceiling fan, & put daylight led lites in it. This has seemed to solve most of my problems. I still need more room but I'm just happy to now have a dedicated sewing room.
Although this morning it's -17 degrees so not sure about the heat vent being closed.