[notfarnow]

Just to be clear, are you talking about using waste oil in a wood furnace in your shop or in your home?

I've seen a few drip-feed systems that are crude but work fantastically. Even then, I'd hesitate to use them in a building I couldn't afford to lose... no way will any insurance company cover them.

I've looked into buying a proper waste-oil furnace to heat our home; many are designed to use either crankcase oil or used vegetable oil. Problem is, none are approved for residential use, so insurance would be out the window.

What some have done to get around this is to set up a waste-fueled hot water furnace in a small outbuilding (like a garden shed) behind the house, and pipe in the hot water through buried pipes. I'd propbably consider that if I was paying to heat with oil, but we use wood heat which is pretty damn cheap.