I was on a call for a furnace and duct cleaning in Nanaimo BC.It was a split level house,married couple with 2 kids.When the customer answered the door i introduced myself and my swamper.I then ran thru how we go about cleaning his system.When i finished he led me to his crawl space which was in a closet inside the house and said to call him if we needed anything.I jumped into the crawl,knealt down as soon as I turned on my light all i could see was duct tape hanging down off of all the duct work.I got out and called him over.What part of the house don't you have heat in,I asked.He called his wife.Say that again he said once she got there.What part of the house don't you have heat in I asked again.Their mouths dropped wide open.How the hell did you know that he asked.He went on to tell me that he had hired 6 different companies to come into his home and to tell him why he wasn't getting heat in certain areas and not one of them could help him.Your system was sealed with duct tape and the tape has long since dried up and is now falling off.It was never sealed properly.He hired me to properly seal his system for him.Took about 90 minutes start to finish.I checked back with them about 6 weeks later.He had another problem with his system.Now he was getting too much heat.The system was no longer suffering heat loss with the joints properly sealed.He had never had the system running properly as they bought the house some yrs after it was built.