I do know that all you mentioned does make a big difference. I live in Houston and have my quilting room that is about 14X15 and have 7 lights over the quilting frame. It came with the pot light things in them and I bought the new twirly kind and it made a big difference. I try to use a little iron on the side of the sewing machine not my big one and may use a small fan and it is fine. This room is usually the coldest in the house. I usually have it on 70. Maybe they could add some more vents or another duct. We did that to our bedroom and that was great.
good luck,
Peg-TX
Innova 18"