My uncle’s heater went down in the dead of winter. It just stopped working one night and he woke up cold and couldn’t get the furnace to turn on. He called out an HVAC company. The technician asked him how often he changes his filters. My uncle said that his system doesn’t have a filter and the technician said that that was unlikely. Sure enough, after a little looking around, the HVAC technician found the filter in the attic. My uncle had lived in the house for 5 years and had never once changed the filter because he didn’t know he had one. And so, he had a lot of costly repair because the clogged filter caused the furnace to burn out inside. The the HVAC vents also needed to be professionally cleaned as did the air conditioning component. He went four days with only space heater while the technician worked on his system. My uncle felt so stupid that he had ruined the heating system in his first house due to ignorance. Surprisingly, the technician informed him that his is not a unique situation. The HVAC company sees several such cases every year. I don’t think that make my uncle feel any better about it though. After he told me what had happened, I scheduled maintenance of my heating and air conditioning unit right away. I change my filter religiously but I wanted to make sure everything else was good. I can’t afford a $2,000 repair bill. I thought I couldn’t afford a maintenance bill either but knowing what I know now, It is simply not worth the gamble. Besides, my bill did not end up being that high.