Never try to light an unlit pilot light immediately, as you do not know how long gas has been filling the room, and it could potentially cause an explosion or start your house on fire. Check your fans and at both too little tlc and inspect all of hvac service, testing and at each step of components are replacing. What Does Furnace Maintenance Cost? Good maintenance does just that. Perform a visual inspection of the heat exchanger, burners, and switches.