Note the date of this review, Nov 2012. Yes! Air Conditioning came out for a Fall maintenance in Dec 2009 and told me I had a crack in my heat exchanger and turned off the gas valve on my furnace. I did get a second opinion that day but can't remember who came out. They confirmed what Yes said and showed me with a detector that I had high carbon monoxide levels being released. So I have been without central heat for 3 years. Although Dekes was referred to me some time ago, I was still skeptical and never called. I finally relented and scheduled an appt. I spoke to them yesterday, Friday, and they showed up today (not late, but earlier than scheduled). He found no cracks and NOTHING wrong with my furnace. He turned the gas valve back on and I have heat for the price of a service call. Yeah! I have a carbon monoxide detector in my house. And we have never felt any effects of carbon monoxide, I believe Yes and the other were short on revenue that year and they were going to make me their sucker. I'm sorry for whoever they picked on after me. It would be my recommendation to NOT call anyone but Dekes. Even if they determined the furnace might need replacing, he assured me it wouldn't be the $6500 that Yes quoted me! THANKS, Dekes!