The Clean Burn Model CB-140 is the smallest waste oil furnace we offer. It produces approximately 140,000 BTU/hour making it ideal for smaller garages and workspaces. You get all the benefits of burning your waste oil for heat in the most compact, economical form with this furnace. Even our smallest models have the longest cleaning intervals in the industry, so if you are looking to heat a small space with a low-maintenance waste oil furnace, the CB-140 is for you.