How to Clean Your AC Condenser Unit Effectively

There are two parts to a home air conditioner system. Okay, so there are a lot more than two, but there are two big components that require periodic cleaning.  One of the maintenance tasks that you, as a homeowner, can do is to keep the condenser unit (the outside component) and the evaporating unit (the inside component) clean.

We’ll take you through the steps of cleaning the AC condenser unit, ensuring you enjoy cool air on demand. It’s not hard to begin cleaning your AC condenser, but there are definitely things to know before you get outside to clean it.

Identifying The Parts

Exploded diagram of a typical home AC system.
Photo Credit: – Exploded diagram of a typical home AC system.

The condensing unit has three main parts: the compressor, fan, and condenser.

These components combined are responsible for dissipating the heat generated within an air conditioning system. It might seem like an oxymoron, but to cool a house, you have to generate heat. It’s the exchange of hot and cold that allows the Freon inside the system to work and, by default, cool your home.

The compressor moves the Freon between the condenser and the evaporator inside to chill the air.

The condenser acts as a radiator to disperse the heat generated in the cooling process to the outside air. It acts just like the radiator in your car.

The final component is the fan. It generates airflow over the condenser to keep the unit cool, prevents overheating, and is the only sound you often hear in a functioning air conditioning unit.

These three components all work with gas, either ambient air or Freon. When the airflow is impeded, you can have problems that quickly escalate from a free, easy fix to perhaps thousands of dollars if your air conditioning system suffers from heat damage.

Maintain Optimal Airflow: Clean Your AC Unit

Top view of external air conditioner.
Photo Credit: Randy Tucker – Typical large-sized home air conditioner.

The condensing unit has to have unimpeded airflow. The fan pulls the air down from above, but it then flows out the four sides of the condenser enclosure.

The most common problem on a condensing unit comes when the screen on the grid surrounding the assembly becomes clogged. The unit sits outdoors, so it is susceptible to debris, lint, tree cotton, and weeds growing up around it. All of these can affect airflow.

Deweed the Exterior of Your AC Unit

American Standard air conditioner unit outside.
Photo Credit: Randy Tucker – Morning glory vines before removal.

Morning Glory, also known as bindweed, is one of the worst. The tiny vines climb up the screen, grow out, and block airflow.

A second big cause of blockage, at least out west, is cottonwood lint. The cotton that grows and then releases into the air from female cottonwood trees creates clouds of wind-blown lint. These clumps follow the air currents and often end up plugging the condenser assembly.

Remove Debris From the Grill

Remnants of vines growing on the condenser unit.
Photo Credit: Randy Tucker – Remnants of vines growing on the condenser unit.

The good news is that this is easy to clean.  Physically pulling out the debris by hand is the first step. The second is to cut the roots of any climbing vines that work their way up the assembly. They’ll dry out quickly and disappear without roots.

The third step is to thoroughly rinse the screen with a high-pressure garden hose or, better yet, a pressure washer. This is usually done from the outside without removing the fan.

Disaabmle the Unit and Clean the Fan

External air conditioner with weeds growing on it.
Photo Credit: Randy Tucker – Not cooling and return lines connecting the condenser and evaporative units.

If your AC unit is severely plugged, you may have to unscrew the eight to 12 sheet metal screws holding the fan assembly on the frame.  Carefully lift the fan, making sure you don’t disconnect any wires. If you have to remove wires, take a cell phone picture of the wires so you’ll remember where they go when you put everything back together.

With the fan removed and the air conditioner turned off. Wash out the inside of the screen.

Reassemble the Unit and Test It

Power control for the condensing unit.
Photo Credit: Randy Tucker – Power control for the condensing unit.

Put everything back together, and you’ll be good to go.

Also, make sure to test the AC unit to ensure that you put all the wires and components back where they belong.

Read more from us: How to Diagnose and Maintain Your AC Unit

Although cleaning will keep your AC unit running at its best, you might run into issues that require further attention or maintenance.