I had to visit a re-opened government office recently. I remarked on how stiflingly hot it was in there (circa 30 vs outdoor 20 dec C). The clerk said, you should see us in Winter, it's 5 layers.
Which immediately reminded me of when I last worked in an office. Was glad to return to my temperate house with that modern innovation, windows with hinges allowing an open aperture to be formed when needed.