Yes, in many cases, you can use your existing furnace with a heat pump to create a hybrid heating and cooling system. This setup is known as a "dual-fuel" or "hybrid" system. The heat pump provides efficient heating and cooling for milder temperatures, and when outdoor temperatures drop significantly, the furnace can automatically kick in to provide supplemental heating. A control system manages the switch between the heat pump and furnace based on the outdoor temperature and your preferred settings, ensuring optimal efficiency. However, it's crucial that your existing furnace and ductwork are compatible with this setup, and you may need professional installation and adjustments to make it work seamlessly. Consulting with an HVAC technician is recommended to assess your specific system's compatibility and determine the best configuration for your needs.