The condenser is the part that sits in front of the radiator--the compressor causes the refrigerant to become hot (by putting it under pressure), the condenser allows airflow to cool the refrigerant, then the pressure is lowered, causing the refrigerant to become colder than ambient temperature, then the refrigerant is piped into the interior of the car and through a smaller condenser/radiator, through with air blows, and is cooled, and flows out the vents (think that's right...) Anyway, the condenser is expensive too.