Do you have one or two large, metal boxes outside of your home? Those are your AC system’s condensing units. Inside your condenser is a compressor (the heart of your air conditioning unit), refrigerant, a condenser coil (either copper or aluminum), a capacitor, an electromagnet, a fan, some relay switches, and other electronic and mechanical components that vary from system to system. The condenser is where a lot of action happens to get you to comfort temperatures; it’s where the refrigerant is compressed and pumped to the evaporator coil, and where the refrigerant returns to release heat.