I am in the process of searching for a new oil fired boiler to replace my old one. Natural gas is not available to my site so I would like to install a boiler that would allow me to burn pure cellulosic biodiesel or if unavailable at this point, a biodiesel blend. At this time I am researching Buderus and Viesman boilers. Is there any other make of boiler that you would suggest, and what is your opinion of Buderus and Viesman. My house is properly oriented to the sun (Connecticut, 14 degrees east of south) and has been designed, remodeled and detailed to take advantage of the Passive Solar for our site. I am a professional builder and have been designing and building south facing solariums and sunrooms, as well as energy efficient retrofit detailing of existing houses, since 1982. I have cast iron radiant hydronic baseboard, and the sunroom is heated with a radiant hydronic gypcrete thin slab. The floor plan of my house (2200 square feet)is very open after remodeling and allows very good natural ventilation and heat flow. I am planning to install PV panels in the near future and will be installing solar domestic hot water to compliment the boiler at the end of this year. I checked the online Greenspec directory and only found gas furnaces. Do you have suggestions as to where to look for other products? Thanks for your help. Edward J. Palma