all winter even 5/F my worm bin/compost bin was above 100/F. It is nothing more than a 90 inch diameter plastic ring about 24" high filled with leaves (bagged from riding mower so they are chopped a bit) and now and then 25 gallons of food waste was dumped in and mixed with shovel. Worms hang out at lower levels and the top was steaming all winter. Very cool I could warm my hands easy, methane was present but not horrid. This was in pole barn but NOT closed in real tight so it could vent out to outside easy nuff. Next winter I cam using a COIL system using pipes filled with OLIVE OIL and a on off pump that can transfer the fluids IN to my shop and coil on a well that will be the radiator. Never know until you try right?