When you are at 27,000 feet above Aboyne surrounded by nothing but the very best polished canopy, a bunnet is quite important.
We once calculated that if you could keep the canopy into sun going up and down the wave, then that was the equivalent of a 1 KW heater.
Your feet were another problem for they were underneath the instrument panel.
I had a mate who was a Chief Tech at Brize Norton and he invented heated boots. The experiment was not entirely a success and he came down with singed feet. We all thought it was quite funny and a good night was had in Balnacoyle!