The air filter was totally gross and dirty
If the air filter in your heating or cooling system is dirty and polluted, it will not work the way it should.
The air filter should trap dirt, dust, and indoor air pollutants.
When the air filter is gross and dirty, indoor air particles end up in the system and that can cause damage. Dust and dirt can cause furnace and air conditioner problems. It can cause problems with the evaporator foils and eventually lead to system breakdown. A clogged and dirty air filter can also lead to a fire. A few years ago, I was working as a volunteer firefighter and there was a call at 2:00 in the morning. Everyone hurried to get dressed as quickly as possible so we could contain the damage. The fire was down the street from my favorite video game store and I knew the building very well. The older building had not been remodeled in a long time. The ductwork was old and falling apart and the owner of the building was not taking care of the place. He was running the heat to keep the plumbing from freezing up, but he wasn’t handling regular maintenance or having someone else do it for him. The gross and dirty air filter caused a fire and half of the building was lost. I’m sure that the customer had insurance, but the building required a lot of construction in order to be viable again for use. It’s been about 10 years since the fire and the building is still in the same shape that it was and the lot is a disaster.