Hi! I just moved into a house that is super insulated and passive solar. It is a two story with the downstairs a daylight basement (about 650 sq ft up and 600 down). The gas heaters (one upstairs and one downstairs) did good till the temp dropped below freezing. Then they could barely maintain 60 deg. I also burned about $250 worth of gas the first month of cold weather. The BTU ratings for the heaters add up to about 10,000, not enough. Being a life long wood burner I added a Jotul black bear (too big, but I got a good deal and if I ever want to add on ...) Anyway, now its 85 upstairs and 60 down. I know that heat rises, duh, but I ran a 6" duct (temporary) from the ceiling upstairs to the floor downstairs, in it I put a small circulatory fan(unknown cfm). It moves air pretty well and did add five degrees to the downstairs. What I'm looking for advice on, is if anyone knows of a good fan/system and or if a homemade water jacket to a furnace downstairs would be a good idea. I don't want to burn fuel/gas and adding a chimney to the downstairs is not happening. Also when the sun comes out it heats the upstairs much more then the downstairs... Any ideas or advice would be greatly appreciated(except the ones that involve lots of $) I'm fairly crafty and am not afraid to cut holes etc... Thanks!