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How Does an Air Conditioner Work?

An air conditioner is one of the best ways to cool your home or office on a hot day. Most people don’t give a second thought to how they work, but how do they cool your indoor space? 

An air conditioner works by moving the heat from inside your home to the outside and releases cold air back inside. It has a liquid called coolant flowing through it, which absorbs the heat, and converts it into a gas. The coolant is then turned into a liquid to start another cycle.

In this article, I’ll provide an in-depth explanation of how an air conditioner works. Let’s begin! 

How an AC Works: A Step-by-Step Walkthrough?

An air conditioner’s operation starts with a signal from your thermostat to allow the coolant to flow through the appliance and absorb the hot air. The hot air is removed and flows outside, leaving your home comfortably cool. 

To better understand how an air conditioner works, it’s wise to learn about the appliance’s 4 main parts:

  • Refrigerant: This is also called the coolant and is the lifeblood of your air conditioner. It carries and releases heat to the outdoors. 
  • Evaporator coils: These are the main parts of an air conditioner’s indoor component because they absorb heat from your home. You should keep them spotlessly clean to ensure they work optimally.
  • Condenser coils: These are the primary parts of the outdoor part of an air conditioner. Air is released to the outdoors through condenser coils and, like the evaporator coils, they need regular cleaning for efficient functioning.
  • Compressor: This is the heart of an air conditioner. It moves the refrigerant to the condenser and evaporator coils.

To help you understand this process, here are the main steps involved in an air conditioner’s operation:

1. The Thermostat Signals That Your Room Is Too Hot

An air conditioner begins working after you press a few buttons on your thermostat to set your chosen temperature. This triggers sensors that determine your existing indoor temperature. If the temperature is above what you’ve selected, it will signal the start of a cooling cycle. 

This involves the compressor turning on so that the refrigerant can flow through the air conditioner, and the fans can start working. 

Read: How To Troubleshoot A 2-Stage Air Conditioner?

2. The Coolant Absorbs Heat From Your Indoor Space

The cold refrigerant in the evaporator coils will come into contact with the hot indoor air and absorb its heat in the process. As a result, the refrigerant becomes warmer, and the air in your home becomes cooler. 

If your indoor air also has excess moisture, the vapor becomes water because of the condensation when it comes into contact with the coolant. As such, an air conditioning unit is also a dehumidifier and comes with a tray that collects the condensed water and drains it outside so it won’t trickle into your house or the unit and cause damage.

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3. Cool Air Blows Through Your Home

The cool air around the evaporator coils circulates indoors to keep you comfortable and cool. The fans handle this task and need the correct placement to ensure optimal air circulation. When using a central air conditioner, the cool air will travel through your home in the ductwork, while a split or window unit blows cool air into its dedicated room.

A split air conditioner lets you set the temperature differently in each room, and you can turn it off in unoccupied rooms to conserve energy. This can be a huge saving when you consider that 6% of energy costs in the U.S., translating to approximately $29 billion, are attributed to air conditioners.

Read: Top 5 Common Problems With Two-Stage Air Conditioners You Need To Know

4. Heat in the Coolant Is Dumped Outdoors

Like a sponge, the coolant eventually reaches its limit in the amount of heat it can absorb. It thus needs to release the heat outside. As the coolant flows through the condenser coils in the appliance’s outdoor section, it dumps the excess heat. As long as your coolant is hotter than the outdoors, it will keep releasing heat, and only stop when it achieves equilibrium.

5. Fans Blow the Hot Air Outside

You need a system that allows heat from the coolant to move outdoors faster so that your home can remain comfortably cool. Powerful fans blow air across your outdoor unit’s condenser coils to cool the refrigerant further. This allows more heat to move to the outdoors quickly.

You may notice that it feels warm around your outdoor air conditioning unit, evidence that it’s working as it should. Since the unit is in an open place, the heat shouldn’t worry you because it will dissipate. The ideal location for the outdoor unit is the same as that of a heat pump.

6. The Cold Refrigerant Flows Back to the Indoor Unit

Once the coolant attains equilibrium with the outdoor air, the compressor will pump it back to your air conditioner’s indoor unit to start the cycle. This continues until your thermostat’s sensors detect your indoor temperature is above what you have set. When this happens, the thermostat triggers the start of another cooling cycle.

How To Maintain an Air Conditioner?

With the knowledge of how your air conditioner works, you can take the proper steps to maintain it to serve you for longer and save you the money you’d spend on repairs or high energy bills. 

Here are some ways to maintain air conditioners:

  • Clean the space around your outdoor unit to keep it debris-free. You should have roughly 24 inches (61 cm) of clear area around your outdoor unit. 
  • You don’t have to blast your air conditioner at the highest setting when no one’s at home. Consider installing a programmable thermostat so you can set higher temperatures when no one’s home and lower ones to keep people comfortable when people are home. This ensures your compressor doesn’t work as hard and can save you a lot of money on energy costs in the long run. 
  • If your condenser unit isn’t leveled, it can lead to premature compressor failure, so place it on level ground. 
  • Change the filters at least monthly because dirty filters reduce an air conditioner’s efficiency.
  • The condenser and evaporator coils have fins that can be bent and reduce an air conditioner’s efficiency. Regularly check your fins to ensure they’re straight and have a fin comb that will straighten them when bent.
  • Leaks can lead to an airflow loss of approximately 30% through your ductwork. Find and seal the leaks with foil tape if small and duct mastic for the large ones.
  • Insulate the ducts in crawl spaces and hot attics to keep the air cool. You can use rigid foam, batt, or spray foam insulating.
  • Perform air conditioning maintenance at least annually. This is best done by an HVAC professional and is well worth the cost because an inefficient air conditioner can increase your energy bills. 
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From the article above, you can learn how your air conditioner works, its main components and how best to maintain it. You can now troubleshoot a few issues with your unit, but getting a professional’s input for repairs is best to avoid any damage. However, cleaning and maintaining your air conditioner regularly is always advisable for it to work optimally.