We referred to City Duct cleaning by our condo office. Everything started well. They gave us a $25 coupon right away as part of a November promotion, so that was a nice start. The guys were polite, introduced themselves and got right to work. However they didn't cover the vents, which presumably is step one. Dust and crap blew out of two of them, one in our bedroom and another right above my desk, sending dust right across the room. I called the office to complain, and as I was doing that the guys started covering the vents. Liz (or Lisa, I forget) agreed this was unacceptable, and offered my a 10% discount or a free deodorizing spray for the ducts, but at first refused to honor the original $25 coupon as well. She asked the owner and called back and ultimately agreed to let me keep that and I took the discount. They cleaned as best they could with a shop vac, finished, left, I turned the furnace back on, and dust and crap blew out of the ducts again, all over my computer, desk, and out of other vents in the unit. The vents have continued to do this, my wife and I are stuffed up and sneezing, and I am calling a second company to come and do it properly.