On Tuesday, December 25, 2018 at 9:53:19 PM UTC-8, wrote:
As we know, flying in wave with the sun shining, much of the cockpit stays reasonably warm, but the feet, down in the shade, get cold. So, as I'm here at home on a cold night with a fan helping distribute the heat from the wood stove to another room, it occurred to me that something like that may be possible in the cockpit? A small fan (using a fraction of the electric power that the typical instrument panel uses), perhaps with a short duct, could move sun-warmed air towards the feet. Has that been tried? Does it help? Would it use more electrical power than electrically heated insoles?

Back when I flew an HP-14 which had a canopy that extended forward over the rudder pedals, my feet were much warmer in cold but sunny weather than they are in my current glider. As long as I was pointed towards the sun, that is - typically pointed into a West wind in the afternoon. As soon as I turned around to the East the cockpit temperature plunged.

It's not sun warmed air at play. It's sun warmed legs/feet.