The air filter had never been changed.

It had been a couple years since my wife and I were able to go on vacation without the kids.

Some friends of ours were going away for a weekend and invited us to go along.

Our daughter was almost eighteen, and we thought she should be mature enough to handle staying home and babysitting the eight and twelve year olds. We asked her to make sure everything was safe and we also asked her to make sure the air filter in the air conditioning unit was changed. She promised things would go perfect. We told her exactly what we were expecting from her, including not having her boyfriend over. We wanted her to babysit and not be fooling around with her friends. We also told her again, that we wanted her to change the air filter. I left explicit instructions on how to change the air filter. I guess it was too much to expect. When we got home, everything looked good, but she said she couldn’t change the air filter. It was stuck inside the air filter. She called a friend whose dad was an HVAC technician and he had to pry the air filter out. Then her friend’s dad put a new air filter inside. She said he told her it was because the air filter was so dirty. I had to look at my wife, knowing if it was that dirty, it was my fault. I thanked our daughter for thinking so wisely and getting the air filter out. We paid her for babysitting and sent her off with her friends for a day at the beach.