Duct system design is an important part of any home’s forced-air heating and cooling system. If not done right, it can result in years of energy losses, decreased efficiency, and possibly even lowered air quality. Your ducts’ job is to deliver conditioned air throughout your home, and then return air to the HVAC equipment to be reheated or cooled. If air is being lost through leaky or defective ducts, or heat is transferring in and out of uninsulated ducts, you’re paying to condition air that’s not getting where it’s supposed to go.