When my heat turned on for the first last year, I heard of mayflies nesting in ductwork before.
I called the HVAC company who asked me if I was sure the mayflies had come out of the ductwork? They were all over my house and hovering on the wall over the air vent in my kitchen.
I couldn’t cook because I was afraid they would get into my food. She told me she had never heard of mayflies in ductwork, and I told her welcome to my club. I wanted the ductwork cleaned and sanitized, and I wanted to know how the mayflies got inside. She said she didn’t know how they go inside, unless there was a crack in the ductwork, and the HVAC technician would need to find that. I felt like I was talking to an idiot. She didn’t have an original thought in her head. I told her to send the HVAC technician to the house. I would call an exterminator to make sure there were no other creepy crawlies hanging out in the ductwork, and then their HVAC company could repair, clean, and sanitize my ductwork. She was smiling while talking and told me that was smart thinking. She wished she had thought to tell me that. The exterminator was at the house the next morning, and the HVAC technician arrived the same afternoon. He called to have the ductwork cleaners come to the house. He had found several small cracks in the ductwork, but nothing the ductwork cleaners couldn’t repair. Within three days, the mayflies were gone, and my ductwork had been cleaned, repaired, and sanitized.