You've made the decision – it's time to replace your heating or cooling unit. As you work with your local Lennox® dealer to find the best product solutions for your home, you may be surprised when they recommend that you replace your system's counterpart, the furnace or air conditioner, as well to ensure you have a matched system. It may not seem like you need to replace your furnace in the middle of the summer heat or your AC in the chill of winter, but there's good reasoning for replacing both of your home's units at the same time. All air-conditioning units and heat pumps are specifically designed to work with matched indoor units, like furnaces or air handlers, for optimum efficiency and performance. While your outdoor cooling system may "work" with indoor units, including older systems, it will only operate at its peak potential when paired with the right-sized system for your home. Before you replace your residential HVAC system, take a few minutes to understand the benefits of having a matched system and the impact your purchase has on your product warranties. Read on to learn more.