In 2020, the estimated value of the North American air conditioning market was $52.56 billion.

That figure is more than likely to grow as summers become hotter than they already are. In such cases, especially during heatwaves, the use of air conditioners can be a lifesaver. Do note that thousands of people get ill and hospitalized in the US due to extreme heat.

For that reason, you want to make sure your air conditioner’s outside unit is just as in great shape as the one inside. If the one outside fails, the one inside is sure to stop working, too. So, by knowing what the outdoor AC unit does, you’re more likely to pay better attention to it, which you should.

This guide will cover all the basics you need to know, so be sure to read on.

What Is the Outdoor AC Unit Called?

In the HVAC industry, professionals refer to this large metal box as the condenser unit. You may also hear them call it the compressor or heat exchanger.

For reference, most HVAC experts refer to the indoor component simply as the indoor AC unit. They may also use terms such as air handler or air handling unit.

What Are the Roles of Your AC’s Outside Unit?

Central, packaged, and ductless mini-split air conditioners come with an outside unit. Inside the condenser unit are the compressor, condenser coil, fan, and refrigerant lines. Together, these parts work to expel the heat absorbed by the indoor unit to the outdoors.

The Compressor

To better understand how the compressor works, let’s talk about the indoor unit first.

The indoor unit houses the blower (or fan), which blows air the AC pulls from your home over the cold evaporator coil. The evaporator coil is a set of metal pipes cooled by the liquid refrigerant.

The refrigerant, in turn, is a chemical that absorbs heat from the air and then transforms it into gas. The chemical itself evaporates, turning into heated gas once it draws the heat from the air.

The blower continues its work by circulating the now-cool air throughout your home. During this time, the heated gas moves out of the indoor unit into the outdoor unit.

The compressor is what allows the refrigerant to get into the evaporator coil in the first place. It’s a pump that allows the refrigerant to move in and out of the indoor and outdoor units.

The compressor’s primary job is to increase the refrigerant’s pressure and temperature. It’s thanks to this pump that the refrigerant can liquefy or vaporize as needed.

The Condenser Coil

From the compressor, the refrigerant gas flows into the condenser coil. Unlike the evaporator coil, the condenser coil is hot, liquefying the refrigerant gas. Once liquefied, the chemical then travels to the indoor unit’s evaporator coil.

The Condenser Fan

The outdoor unit of your air conditioner also has its own fan, known as the condenser fan. It sits right on top of the condenser coil, blowing air over the hot metal to cool it off. This allows the outdoor unit to release the collected heat to the outdoor air.

The Refrigerant Lines

Refrigerant lines are two copper pipes that transport refrigerant throughout the system. They connect the outdoor unit to the indoor unit.

The larger pipe, also known as the suction line or return line, carries cool refrigerant. Insulating materials cover this line to keep the gas as cold as possible.

The other uninsulated pipe, which is narrower, carries warm refrigerant. HVAC professionals usually refer to this as the liquid line.

What Can Go Wrong With the Outdoor Unit?

Now, you know that without the outdoor unit, the heat absorbed by the indoor unit won’t have any place to go. That’s why it’s vital to keep the exterior AC unit free of obstruction at all times. Otherwise, all that hot air won’t be able to escape to the outdoor air.

If hot air builds up inside the condenser unit, the condenser coils can overheat. This can lead to the refrigerant taking longer to cool within the evaporator coil. As a result, your indoor unit can also take longer to provide you with cool, refreshing air.

Also, since the condenser unit is outside, it’s at the mercy of outdoor elements. A notable pollutant is particle matter (PM), consisting of dust, dirt, and soot. PM is a huge problem in the US, affecting at least 21 million people throughout the country.

Over time, those pollutants can form layers of residue on the outdoor unit’s many parts. Filth on the condenser coil then inhibits heat transfer from the coil to the outdoor air. This forces the compressor to work harder and the entire unit to develop early wear and tear.

Moreover, a dirty coil can cut your AC’s cooling efficiency. This translates to longer cooling times (also called cycles) and higher electricity bills. You may also feel as if your home is more humid than usual.

In severe cases, your indoor unit might even seem like it’s circulating hot air in your home. This can happen if the collected heat can’t escape or the outdoor unit is overheating.

What Can You Do To Avoid Condenser Unit Woes?

Remove leaves, twigs, and anything else that may be blocking your outdoor unit. If you have time, you can use a dry vacuum to eliminate dust, debris, and grime build-up on the unit’s housing element. All sides of the condenser unit should also have at least two feet of clearance. 

It’s also a smart idea to schedule your entire system for annual maintenance. This includes deep cleaning and inspection of both the outdoor and indoor units. It’s a preventative practice that can also help you catch problems before they worsen.

Keep Your Outdoor AC Unit Pumping With Proper Maintenance

If your indoor unit is like the lungs of your air conditioner, the outside unit is pretty much like its heart. It’s this outside component that pumps refrigerant throughout your system, after all. More than that, it expels hot air from inside your home to the outdoors.

That’s why it’s vital to shower it with the same amount of care and attention you show toward your AC’s interior unit.

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