So, your air conditioner has finally quit. A technician found that the condenser (aka outdoor unit), needs to be replaced. The other main part – the evaporator - is still OK, so you’re tempted to just replace the condenser. Don’t do it.
Let me explain. There are two main parts in an air conditioner, the evaporator and the condenser. You’ve never seen the evaporator. It quietly sits inside the ductwork and absorbs heat from inside air into the refrigerant. The condenser sits outside of the house and looks like it’s doing all the work. Actually, it’s only doing half the job. The condenser squeezes heat out of the refrigerant into the outside air.