We recently purchased an outdoor wood boiler and it is proving to be quite a nice investment :)
We've had a wood furnace in the basement for the last couple of years and loved how it helped with our propane bill! But we didn't like having to carry wood downstairs and the mess it left. We also didn't like that it filled the house with smoke twice! So we decided it was time to invest in an upgrade :)
The wood boiler burns wood to heat water that is then brought into the house and runs through the furnace and the hot water heater. Both the furnace and the water heater have attachments on them to make the wood boiler work, but they function the same as the did before in terms of heat sourcing. The furnace still runs through all the existing duct work.
My scrapbook room is currently 74.5 degrees...and I'm lovin' it :)