A few weeks ago, I started to suddenly begin to notice a dank odor inside of our house. When I couldn’t do anything to locate the source of the odor, I thought I was completely losing my mind finally. The odor seemed to dissipate into the air without reason, & I forgot for a few nights that it wreaked at all. Until last weekend, the awful odor was back again worse than ever. I sprayed perfume all over the house, but the awful mysterious odor was still lingering in the air. I tried our very best to pinpoint the cause of the odor all over the house, but it seemed to be coming out of our air vents in every room. When I turn off the Heating & A/C system, I immediately couldn’t odor anything in the air. I decided it was past time to contact our Heating & A/C dealer. I heard a few horror stories in the past about poor animals dying inside of the Heating & A/C ducting. I prayed this was not the cause of the odor in our house. With the air conditioner system up and running, the corporation could odor the same awful odor that I had tried to describe. The Heating & A/C corporation went into the Attic to view all of the Heating & A/C ducting up there; He was in the attic for a long time, but soon he came down to supply the awful news that a hawk had found its way into the attic. It made a small bed next to the Heating & A/C ducting and all of the bird feces had built up in the attic. This was the culprit of the lingering sour odor. Too bad the bird was endangered, so I couldn’t do anything about my stinky house!