https://www.youtube.com/watch?v=nR33FIFU3zY&feature=youtu.be Here's part 1 of Morgan Brown's excellent series on how he heats his greenhouse with his compost pile. This insulated in-ground compost box is impressive!
I envy the cover material at this place! Leaves, pine needles (don't need a lot), dead grass, etc... I was asked to build up a fresh pile, so I added a good 12" of base material, then added the food scraps followed by another 6" of cover materials. While I doubt it will start up since it's 20 degrees out, as soon as it's ready it'll take off. In the meantime, there's a few months' room for weekly contributions until the temperature stays above freezing for a few days. I'm sure we'll get our January burst of 70 degree weather for a day out of nowhere, anyway...
https://www.youtube.com/watch?v=edVH6Qzu-t0