I have up to 20 vents cleaned up by Greg. He has been very patient and professional in his job, leave the field clean and tidy. Sealed and plugged the drilled holes very nicely. Greg also spent extra time answering our questions, advising on furnace maintenance. Very friendly and knowledgeable to talk to. This is the first time duct cleaning ever since we moved to our place, and it has been an excellent experience to us. Wonderful job done! Thanks Greg.