The correct-sized HVAC unit depends on the square footage of your home, as well as the number of rooms; during your free, in-home consultation, a Home Depot Installer will help you find the right-sized HVAC system for your home.
Remember, bigger is not necessarily better. An HVAC system that is too large for your home may not regulate temperature or humidity as efficiently or effectively as a correctly sized one. A mismatched system may also need repairs sooner.