I had a airwick plug in plugged in to a socket. I kept smelling a odd smell. I thought it was coming from my crawl space because a socket is right over my vent. Are days of searching the room looking for the smell. I finally unplugged the airwick. And the smell was the airwick device burning. Glad I found it when I did! I'm not sure if the device was defective or not. Just wanted to make the company aware of this issue.