While some furnace maintenance tasks, such as changing air filters, can be done by homeowners, it’s generally recommended to hire a qualified HVAC technician for more complex tasks, such as inspecting the heat exchanger or replacing worn-out parts. Furnaces involve complex systems and safety hazards, and improper maintenance or repairs can lead to safety risks, reduced efficiency, or even void the warranty. A professional technician has the necessary expertise and equipment to perform maintenance and repairs safely and effectively.