We had an outdoor woodboiler, but sold it, and we are searching for a more efficient heating source that will tie into our ductwork. We are looking to heat a finished basement and two floors, 3,000 sq. ft. total, in our 14-year old 1 1/2 story. We have hot water radiators in the basement plus another water line to the garage and bonus room, which we plan to finish some day. The rest of the house is forced hot air from our oil furnace. We still have the heat exchanger from the outdoor boiler. We initially were leaning toward the wood gun, but the price is leading us to explore other options. We also really like the Kuuma, but we have flexible ductwork that is not high temp, and it is our understanding that you have to use high temp with the Kuuma. Now we are researching the Harman SF260 or DS Machine boiler or even the AHS coal/wood boiler due to the fact that they are cheaper. We plan to burn wood; not coal. Can anyone share their experience with burn times on these boilers, efficiency, and ease of use? Thanks for any and all help.