I sew in our basement, half of the basement has vents so they are warm, but not my part. I have 2 large work lights hanging over my cutting table and my sewing table, and initially it is cool when I first start sewing, but the heat from these 2 lights really warms me up. I have a small portable space heater but haven't had to use it. I usually dress warmer when I want to sew but have to take a layer off as it gets too warm then.