There exist plenty of reasons why your furnace doesn’t heat anymore. It will be hard to predict the particular scenario of a solution without a professional diagnostic. Still, here is a list of the most popular issues you can use to investigate your case. Before doing any fixing, make sure the heater’s thermostat is set to Heat. Check both the main electrical panel and any secondary subpanels that supply power to the unit. Now, reset the furnace. One of the basic checks to make when a furnace acts up is to see if the filter is clogged. If not replaced regularly (every one to three months) the filter will become so congested that it will block airflow into the furnace. This means less air is heated, and less heated air reaches the rooms. The problem may not be inside the furnace itself, but in the ventilation system. Leaks along the ducts allow heated air to escape, lowering how much reaches the room. If certain rooms in the house are cold, it may be the fault of leaky ductwork. You can’t repair this on your own— call our team to locate the leaks and seal them with caulking, metallic tapes, or replacing duct sections. Surely, if your furnace has been used for many years, it might be overused and too old to function properly. Repairs may manage to restore it for a short time. Unfortunately, it will lose its capacity again and again until it breaks down forever. Contact our customer support to get additional information or arrange a visit of our professional HVAC system specialists.