Most homeowners are unaware that you must also inspect air ducts to ensure they are clean and ready so that the air conditioner can operate at its most effective level.   The HVAC system will have to work twice as hard to create without the cleanest ducting as it would if everything were clear of debris and dirt.   It increases the likelihood that the air conditioner will break down, increases energy costs because of how inefficiently it operates and contaminates the air in the house, making it hazardous and unhealthy. Some indications that your air ducts require maintenance include the following: Mould development in the ductwork. Ducting with dust. Energy costs are increasing.