The "service" provided was a complete scam. I was uncomfortable with the people that came to my house and then felt pressured to have them do more work than I had paid for with the group-on. Not only was nothing cleaned but the people that came didn't even know how the furnace worked or what the various parts were - let alone were they able to clean them as they said they had. Two days later I had another company come out to inspect the work, or I should say lack there of, and they documented exactly what needed to be done to include pictures of the uncleaned furnace and of the items found still sitting in my ducts. Complete disgust with TLC.