Your home's furnace is working hard this time of year, and your family is depending on it to keep all of you warm. Furnace problems will not only leave you cold--a malfunctioning furnace can cause a fire or release dangerous levels of carbon monoxide. Keeping your furnace clean and well cared for will make its job easier, which will save wear and tear and keep your furnace healthy longer. A healthy furnace will heat your home more evenly, save you money on your energy bills, and avoid expensive and potentially dangerous furnace malfunctions. Read on to learn the steps to a happy furnace.