Do Air Conditioners Take In Air From Outside?

Air conditioning has become commonplace around much of the world, included in private homes, work places, and public buildings to create comfortable environments for people living in hotter climates.

But how did it come about, and just how exactly do they work?


Whilst methods of home cooling were employed since the times of the Ancient Egyptians, the invention of what is considered the modern air conditioner is an American inventor called Willis H. Carrier.

After inventing the concept for the electrical air conditioner in 1901, the first was eventually installed one year later in 1902.

By 1915, The Carrier Air Conditioning Company of America was formed, basing themselves in Syracuse, New York. The company is still going strong today, with an estimated turnover of $18.6 billion US dollars, and employing around 53,000 employees as of 2020.

How Air Conditioning Works

Most conventional air conditioners are of two halves: one which is inside the house, and another end that is pointing outside.

When the air conditioner is turned on, warm air is sucked into the machine from inside of the room, flowing over chiller pipes which are kept cool by coolant fluid which is piped through them.

These chiller pipes gradually cool the air, much like the internal workings of a refrigerator. There are also dehumidifiers which remove excess moisture in the cooled air.

This cool air is then blasted back into the room, gradually lowering the temperature over a short period of time.

On colder days, when the air conditioning system is instead used as a heater, the air that is sucked into the machine passes over a separate heating element, which warms the air and sends it back into the room.

What Is Coolant?

In most air conditioning systems, the chosen coolant is a volatile liquid called freon.

Freon is a chemical used as a refrigerant, thanks to the way in which it absorbs heat and becomes a gas thanks to evaporation.

The volatile and easily manipulated nature of freon means that with the help of temperature control, the liquid can be altered rapidly, and used as a delivery system for hot and cold air.

Hot Air Dispersal

Once again, just like in a refrigerator, the coolant liquid flows through a compressor unit, as well as some condenser pipes, which turn it back into a cool liquid, ready to complete the cycle all over again.

Thanks to the coolant being piped through the air conditioner, the hot air attracts itself to the liquid, which then turns it into a hot gas, which is then fed to a grate and out into the external compartment of the air conditioning system.

Once it has passed through into this external compartment, the hot air is dissipated using metal plates. Often, an electric fan is also used to expedite this process and increase efficiency.

Do They Use Outside Air?

The short answer to this question is no.

Air conditioners are only designed to take in and condition internal air taken from the room they are installed in.

Why Not?

This is to ensure continued air quality, and to remove the risk of outside fuel fumes and smells being brought into the home or building.

This is also important to avoid other pollutants such as pollen, which can cause allergic reactions and hay fever symptoms in many people.

Air Conditioning In Cars

Air Conditioning In Cars

Car air conditioning systems work much in the same way, albeit on a smaller scale.

The cooling elements are kept inside the dashboard of the car, and when the hot air from the car is sucked inside, the same process occurs, using the coolant to deliver the hot air to an external vent, where it is dispersed into the atmosphere.

The only air conditioning equivalent that does incorporate outside air are the internal vents of your car.

These can be positioned to either face you, or face the windscreen, and channel ambient or warm air from outside the vehicle, pass it through a series of cooling elements, before channeling it into the car itself to alter the temperature.

The efficacy of this depends on the external temperature, and on hotter days this can only succeed in pumping more warm air into the car’s interior.

However, this air circulation system has been replaced in most modern cars by a more sophisticated air conditioning system, alleviating this problem.

The Benefits Of Air Conditioning

More than just keeping our homes cool and stopping us feeling clammy on those hot summer evenings, the implementation of air conditioning into our society has led to a distinct decrease in heat strokes, dehydration, excessive perspiration, and other serious problems, such as hyperthermia.

Along with humidifiers, air conditioning systems are used to promote cleaner, fresher air in hospital environments, and have played a major role in protecting us from harmful allergens like pollen, and some of the adverse effects of long term pollutant exposure, especially in large cities.

However, there are certain negative effects of air conditioning.

The presence of legionella pneumophila, which is a key bacteria in legionnaire’s disease, has been found to thrive and spread in neglected units.

This can be avoided by regular maintenance and cleaning by qualified air conditioning technicians and professionals.

Final Thoughts

And there we have it, everything you need to know about air conditioning systems, and how they work to condition the temperature of the air inside your home.

For many people, a time without air conditioning doesn’t bear thinking about, and when you think of the impact it has had on our personal comfort on a daily basis, it is easy to see why.

So the next time it’s sunny out, crank up the A/C, be thankful of the comfort, and tip your hat to Mr Carrier. We couldn’t have done it without him!