Category - Air Conditioning
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Will Scholfield, Engineer

31 Jan : Updated 17 Apr ● 5 min read

How does air conditioning work?


Air conditioning is a process that is used to create and maintain optimum temperature levels in an indoor space. Often, people think that air conditioning works by creating cold air.

However, this isn’t entirely true.

In this guide, we’ll explain how air conditioning works as well as what the individual components in air conditioning systems do.

How does air conditioning work?

Air conditioning units work by removing the warm air from inside your home and pumping it outside, while releasing the cool air back into the room, reducing the temperature. When liquid becomes gas, it absorbs heat, and in principle, this is how they function.

Air conditioning systems work very much in the same way as your standard refrigerator, in that heat is absorbed inside the system and then removed from the room.

Here’s the process:

  • Firstly, the warm air from the room is drawn into the system.
  • This air flows over the cold evaporator pipes inside, which cools the air down while a dehumidifier removes excess moisture.
  • Meanwhile, the coolant flowing through the chiller pipes absorbs the heat from the air blowing past and evaporates, turning from a cool liquid to a warm gas.
  • This warm air is pumped outside while the coolant flows through a compressor unit and a condenser, which turn it back into a cool liquid.
  • Cold air is then re-circulated into the room where it mixes with the existing air and reduces the temperature and humidity.

Inside a unit, there are a number of different components that manipulate the state, pressure, and temperature of the refrigerant, allowing the unit to do its job and cool the room.


What do the separate air conditioning components do?

We know that air conditioning units require a coolant liquid that is pumped through the coils to cool down the air. For the air conditioning process to work, this refrigerant circuit has to have three key components.

The air conditioning evaporator.

The warm air from inside your home is drawn in and passed through an expansion valve which regulates the flow. It is then blown over the cold evaporator coil, which absorbs the heat from the air. As the refrigerant inside the coils absorbs the heat, it changes back into a gas and moves towards the compressor.

The air conditioning compressor.

The compressor in an air conditioning system acts as a pump, decreasing the volume of the gas and raising its pressure and temperature for the condensing process.

The air conditioning condenser.

The air conditioning condenser takes the heat collected from inside the room by the refrigerant, now in vapour form, and pumps it outside where the outside air absorbs the heat and changes the state from a gas back to a liquid.

Once the heat has moved outdoors, the cold refrigerant travels back indoors to the evaporator to repeat the process.

Do air conditioners only cool the air?

A common misconception is that all air conditioners do is reduce the temperature of the air in a space. While this is its biggest job, they do much more than that. They also have a number of health benefits too.

The health benefits of air conditioning.

  • Air conditioners contain a filter that removes particles and allergens, such as pollen and dust, from circulating into the air, helping to clean the air you breathe inside your rooms. Similarly, they also act as dehumidifiers. This is because conditioners draw moisture from the air within a room, reducing the humidity.
  • When the temperature increases, you’re more at risk of heat stroke. With an air conditioning system in place, you’ll reduce the risk of heat stroke and other heat-related illnesses.
  • Surprisingly, air conditioning helps to reduce the risk of dehydration. Lower temperatures in a room mean that you’ll sweat less. When you sweat, you’re actually losing a lot of water from your body. It’s important to keep hydrated, of course, but an air conditioning system will help to combat possible dehydration.
  • With more regulated temperatures during the night-time, you’ll be able to sleep much better. Keeping bedrooms cool ensures you’re much more comfortable while you’re sleeping, which in turn will make you better rested for the day ahead.
  • Cleaner air from an air conditioning system means that there is a reduced possibility of asthma attacks with sufferers of the condition. However, it’s also important to change the filter when needed to further reduce that risk.

Other benefits.

There are also many other ways in which air conditioning can be beneficial:

  • Without the need to leave windows and doors open, your air conditioning system can, in theory, ensure your home is secure. It’s much harder for someone without authority to enter your home if they don’t have an open door or window to enter through.
  • There will be fewer insects or bugs in your home because of the air conditioning filters. These filters will also prevent fleas from spreading on your pets’ fur and will keep your home cleaner overall.
  • As you’d expect with open windows, the noise pollution will be high, especially if you live on main roads. You’ll reduce this noise with an air conditioning system. The systems themselves are also quiet to run, as the compressor and fan are located outside of your property.


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How does air conditioning work in the home? We can answer any questions you may have.

Air conditioning may not have been something you’ve thought about in the past, but if you want to upgrade your home’s technology whilst also breathing in cleaner air, preventing common health problems as well as keeping your home secure, then an air conditioning system could be for you.

To find your ideal air conditioning system and unit for your home, you can try out our ‘Find Air Conditioning’ tool. By answering a few simple questions about your home and living arrangements, we can pick out some personalised AC units that would benefit you and your home.

For more information about picking an air conditioning system for you, talk to a member of our team today by calling 0800 193 7777 or by using BOXT’s live chat.

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