We have all heard a noise in the middle of the night and wondered what it could be. The noise probably isn't a ghost but an HVAC unit in need of repair. Instead of a ghost, your HVAC system could be haunting your home.
The air filtration system within your HVAC setup is responsible for ridding the air of environmental debris before it is released back into your home and breathed in by its occupants. The standard recommendation surrounding air filters is to change them every 30-60 days, but that duration can vary depending on a large number of factors.