Set aside 4 hrs or so for a house with around 15 ducts. The ductworks employee arrived on time, was very thorough with his job, knowledgeable and friendly. He had proper equipment and took care to work around the folks in our home (my parents were visiting). He took apart the furnace blower, cleaned it and put everything back together. Washing all the vents added the extra touch that really spoke to the thoroughness of their job.