Air Conditioner 101: How Does An Aircon Work?

In a hot and humid country such as the Philippines, an aircon is becoming more of a necessity than a luxury. This appliance is a godsend that saves us from feeling sweaty and sticky especially during the intense summer months. But have you ever wondered how an aircon makes our rooms cold?

An air conditioner works by sucking in hot air from the room and then replacing it with cool air. This cool air is made by continuously evaporating and condensing a refrigerant gas along the pipes embedded inside the aircon. As this gas evaporates, it absorbs the heat from the air that was sucked by the AC, which is then blown into the room and thus producing a cold environment.

Read on to get a more in-depth explanation of the mechanics behind an air conditioner. I will also explain the different configurations of air conditioners that are available in the market.

How an aircon makes the air cold

Much like a refrigerator, an air conditioner harnesses the power of evaporation to make cold air. An aircon works by taking the heat off the air, transferring this heat outside, and then blowing the same air (now devoid of heat) in to the room. It does this through the process of evaporation.

When a liquid evaporates in to the air, it absorbs heat. This is why your skin feels cold after rubbing your hands with alcohol. This is also why we sweat when our body temperature gets too hot. An aircon works by harnessing the power of evaporation to absorb the heat, but makes it so that the resulting vapor won’t escape. Instead, it gets reverted back to its liquid form to start the cycle all over again.

The refrigeration cycle

An overview of the refrigeration cycle

The refrigeration cycle is a closed-loop system that recycles the same refrigerant gas indefinitely. The cycle goes like this:


It all starts with the compressor. This part is known as the heart of the air conditioner. The compressor increases the pressure and the temperature of the refrigerant gas, and pumps it into the condenser.

Condenser + fan

The condenser is the set of coils located at the back of the aircon. Its job is to condense the hot high-pressure refrigerant gas from the compressor into its liquid form. This liquid is then pumped into the expansion valve. Aside from that, this part also transfers the heat to the outdoors with the aid of a fan.

Expansion Valve

Also known as the capillary tube, this part greatly reduces the pressure of the liquid refrigerant, thus bringing its boiling point down.

Evaporator + Blower

The low pressure liquid is passed along the evaporator coils where – you guessed it – it will gradually evaporate. After this, the low pressure liquid is cycled back to the compressor where the cycle will start all over again.

Air Intake Panel + Filter + Blower

The air intake panel sucks the indoor air in to the AC unit. It makes the air pass through a filter to keep the evaporator clean and to improve air quality. The evaporator is where the heat will be taken off the air, thus making it cold. The blower then blows the now cold air back into the room.

Types of refrigerant gases

If the compressor is the heart of the air conditioner, then the refrigerant gas is its blood. This is the gas that gets evaporated and condensed in the aircon’s pipes.

There are many kinds of refrigerant gases in use today for refrigerators, air conditioners, and other commercial applications. Each one of them have different properties. Back in the day, the most common refrigerant gas was Freon (R-12). However, Freon is a CFC (chlorofluorocarbons) that damages the ozone layer. Freon has been phased out in lieu of more environment-friendly refrigerants because of this.

The most common refrigerant gasses in use in air conditioners today is R-410a and R-32 .To briefly put it: R-32 (Difluoromethane) has less impact on the environment and is generally more efficient vs. the R-410a (Puron) gas. However, one of the drawbacks of the R-32 gas is that it is flammable while the R-410a gas is not. I’ve made a deeper comparison between these gases in a separate article. Go check it out!

Types of air conditioners

While all air conditioners produce cold air the same way, they are configured in different ways to accommodate different price points and tastes.

Window Aircon

This is the most common type of aircon in the Philippines, and it is also the simplest. This type combines all of the components into one unit. It is mounted on the wall, with the compressor and condenser hanging outside of the wall.

Split Type Aircon

As the name implies, this type of aircon splits the aircon into two units: the indoor component and the outdoor component.The indoor component comprises of the air intake panel, filter, evaporator, and the blower. This is connected to the outdoor component (comprised of the condenser, fan, and compressor) by a copper tube.Because of the width of the indoor unit, the airflow will have a wider coverage compared to window air conditioners. making it more efficient in cooling rooms.

I have written a separate article where I compared the split type vs. window type aircon. Go check it out!

Portable Aircon

Much like the window type, the portable air conditioner also combines both the indoor and outdoor components into one unit. The difference is that the whole unit is located indoor. The hot air from the condenser is transferred outside of the house through an exhaust tube that vents out through your window. Also, the water droplets that form because of the condensation will not have a way to escape outside, which is why portable aircons have a water to tank that you’ll have to empty from time to time.

I’ve discussed the merits and demerits of a portable aircon before, and also compared it to a split type AC. Go check them out!


While most people can go about their lives not knowing how an aircon works, knowing so will provide you with information to make better decisions when buying a new air conditioner. It can also help you improve its performance to get more from it – or at the very least, not break it.

1 thought on “Air Conditioner 101: How Does An Aircon Work?”

  1. Oh, my! The owner of my local gym should really have further discussions with a professional to immediately resolve the problem he’s having at the moment. My son told me yesterday that the place became extremely hot due to several broken air coolers. I suddenly remember what you clarified about portable air conditioner and how we could keep it function properly as long as we keep its water tank consistently empty.


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