The national air-duct cleaners association (NADCA) recommends to have an air-duct cleaning every 3-5 years. EPA (Environmental Protection Agency) warns that indoor air can be 2-5 times more polluted than outside air, bacteria and dirt mixed with other toxins can be present and recirculating in your homes air system. Getting a professional air duct cleaning can help you breathe better, make your home smell fresher, and cleans out contaminants that have been recycling in your home and potentially making you sick.