Open HVAC system ends up stinking

This area is usually very comfortable.

I can get by with just an open window and a ceiling fan most of the time. But this year has been nothing but non stop rain. It is hard to keep a window open when it won’t stop raining outside. Thankfully my HVAC system can be switched to an open system. That means that it takes air from outside rather than inside the house. I just turn the thermostat to the fan setting and then go to the utility shed and change it to “open”. Then nice air from outside circulates throughout the whole house but no rain water gets in. It is very nice. Too bad I haven’t used this capability in more than a few years. So when I finally did use it, a terrible stench circulated the house. It smelled like an outhouse. It was disgusting. I opened a few windows, in the rain, then hoped that the smell would just air itself out and go away. After 30 minutes it became clear that this was not going to happen. I had to turn off the HVAC fan and then keep the windows open while running the ceiling fan. Then I had to put towels in all the windowsills. After that I called up our HVAC supplier. I wasn’t sure if the smell was just because of the open system or if there was something very wrong with out HVAC system. It turned out it was just the open system. There was a bunch of dirt, mold, and a dead bird in the intake area. That is all cleaned out now. The HVAC technicians put up a mesh screen so no more stuff gets through into the tubing either. Now, if it would just stop raining, I would be happy as a clam.


a/c workman