Winter will be tough on your furnace if you don’t clean it right. It’s best to do a thorough furnace cleaning before it gets too cold outside. The best thing is you don’t need an HVAC professional to clean the unit for you. There are heating maintenance tasks you can do to avoid being bitterly cold and unsafe. When Is the Best Time to Clean My Furnace? Your furnace should be cleaned in the fall before the temperatures drop much.