The Difference Between Evaporator Coil & Condenser Coil


Evaporator Coil & Condenser Coil For Dallas Homeowners

An air conditioning system has two coils, condenser coils and evaporator coils usually made of copper tubes with aluminum fins. The evaporator coil, or indoor coil, is often described as the “cold” coil because it provides indoor cooling. The coil works by absorbing heat from the indoor air that is blown over by the air handler’s fan. The condenser coil or outdoor coil is the “warm” coil as it rejects the heat as a fan blows outside air over the surface.

This video shows the difference of condenser coil and evaporator coil.


What’s the Difference Between A/C Condenser and Evaporator Coils?

The Evaporator Coil

You might think of your air conditioner as adding cool air to your home, but it’s more accurate to say that your AC unit subtracts heat from indoor air and transfers it outside. That transfer takes place in the evaporator coils on the interior half of your air conditioning system. As the coolant inside the metal coils evaporates, it acts as a heat sink for the air that moves across it from the blower. Copper conducts heat readily, so the coils that contain the coolant are usually made of this metal. To maximize surface area and provide more cooling power, the copper coils have metal fins or vanes surrounding them. In a dual or hybrid heat pump system, the same coils that act as evaporation sites in the summer to cool your home become condensation sites in the winter to provide warmth.

Extracting indoor heat from the air and adding it to refrigerant is the function of the evaporator coil. Installed inside the indoor air handler, the evaporator is continuously exposed to the flow of warm air drawn by the system blower from individual rooms in the house through return ducts. The refrigerant circulating through copper tubes in the coil is a cold vapor around 40 degrees. In this state, the heat-absorbent properties of the refrigerant are maximized.

Heat energy from the warm house airflow transfers through the chilled copper coil tubing and is readily absorbed by the refrigerant flow. With its heat energy extracted by the coil, the cooled airflow is pushed by the blower into the supply ducts and dispersed throughout the house. At the same time, heat is being extracted, the warm air contacting frigid evaporator coil surfaces triggers condensation, which lowers the humidity level in the airflow, “conditioning” the air just as Willis Carrier designed over a century ago.

After leaving the evaporator coil, the refrigerant flows through an insulated conduit to the outdoor A/C component that’s usually directly behind the house. This cabinet contains both the compressor and the condenser coil. Refrigerant entering the compressor is pressurized, concentrating the molecules of heat energy and raising the temperature of the refrigerant vapor to over 100 degrees. This superheated state ensures efficient transfer of the heat energy into the outdoor air, even when the outdoor temperature is high, such as on a hot summer day.

The Condenser Coil

The condenser coil is of similar design to the indoor evaporator coil. However, the difference between A/C evaporator and condenser coil is exactly reversed. While the evaporator coil picks up heat from indoor air, the condenser coil releases heat into the outdoor air. A load of heat energy extracted from your home and compressed in hot refrigerant vapor is rapidly released when refrigerant circulates into the coil and condenses to the liquid. As the refrigerant releases its heat load, a fan incorporated in the unit blows air through the condenser coil passages and heat is dispersed into the outdoor air.

High-pressure liquid refrigerant leaving the condenser coil makes a u-turn and flows back to the evaporator coil. An expansion valve before the evaporator restricts the flow of refrigerant, forcing it through a narrow orifice and converting it back to a vaporized state, ready to absorb more heat energy from your home.

Your air conditioner’s condenser apparatus is outside where waste heat can dissipate to the outdoor air as the heated gas inside it returns to its liquid state under pressure. Like the interior coils, the exterior coils are a heat transfer site; in this case, though, the heat moves in the opposite direction, going from the coolant into the surrounding air with the help of exhaust fans.

Coil Cleaning Tips

If the coil is contaminated with a light dust or dirt not adhered to the fins, blowing low pressure compressed air across the fins or the use of a soft bristle brush may be sufficient.  Applying a plain water or mild detergent solution to the surface, allowing it to sit for a short time then rinsing is employed in some cases.  More aggressive deposits call for the use of stronger cleaning solutions or solvents as required. Call (214) 238-8353 us for your home service and repair needs.

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