When considering a professional duct cleaning company, one of the most important things to consider is what they will use to pull the debris from your duct work. You should consider having a company that uses a rather large cart mounted unit to pull the debris out. This will take much more out and be able to work effectively.
When working with a duct cleaning company, make sure they are professionals. If you decide to get your ducts cleaned, it will pay to have a professional do them as they have the equipment to pull out a considerable amount of dust and debris. Those that use smaller models may not have the highest quality product.