We recently learned you can use biodieseal in an oil furnance, with the problem being getting a source for biodiesel. Our oil this year will be $1.69 a gallon, but you can make biodiesel for about .70 cents a gallon. Any of you ever make it? I called a couple fast food restaurants and they said we could have their used vegetable oil if we arranged advance pick-up - so that part is doable. I also came across a company called Biodiesel Solutions which offers some machinery to do the job - anyone have personal experience with one of these? www.makebiodiesel.com The device is $3000 -cheaper than installing the wood stove or pellet fireplace inserts I was looking at. Opinions?