Why does my HVAC system have a bad smell when it turns on?

A bad smell could indicate several issues, such as mold or mildew in the system, a dirty air filter, or even a gas leak. If you notice a persistent bad smell in your Athens, PA home, it’s important to have your system and Air Conditioner, Heat Pump, Furnace, or Ductless Mini-Split inspected by a Hal Fish Heating and Air Conditioning professional.