How is Oxygen level maintained in Air Conditioned Room

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Oxygen is one of the most essential elements required to sustain life here on earth.

If blood oxygen levels are too low, our body starts to fail.

Without it we will die.

To ask “How is oxygen maintained in an air conditioned room” is an important question.

To answer this I have done a thorough research.

Most of the home air conditioners have no functionality to maintain oxygen levels inside the room. They are meant to cool the room only without no ventilation.

Does AC help ventilate a room

Here ventilation means that outside air comes inside and indoor air goes outside freely.

Most of the home air conditioners like window AC, split AC, or a portable AC does not have the functionality to bring the outside air.

Therefore such ACs cannot ventilate your room.

Your AC only recirculates the indoor air. Aircon’s sole purpose is to cool the room.

However I have seen some window ACs in the US that can bring outside air thus maintaining the oxygen levels. You can see one at Amazon here.

Such units have a lever using which the fresh air vent opens.

But most of the window ACs found around the globe does not have this feature.

However complex HVAC system used inside big malls, hotels, office buildings, airports, etc have the feature to ventialte the indoor area. Such area maintains oxygen level, freshness, humidty, etc.

I have written a complete article exlpaining whether different ACs bring fresh air from outside or not. Do check it out.

Will you suffocate in Air Conditioned Room

There is very low possibility of someone suffocating inside air conditioned room. However people can suffocate if the room is airtight, the room is small, and number of room inhabitants are high due to carbon dioxide buildup.

If you feel suffocation in an air-conditioned room, you’ve probably stayed too long inside. Open the door or windows occasionally.

Usually our rooms are not airtight. There are gaps around window, below and above the door.

These gaps allow air to come in.

A person will open the door occasionally in a day due to everyday chores like washing, drinking, bathing, eating, etc.

This all allows the air to come in and out leading to maintaince of gases like oxygen.

But Let’s say your room is airtight and you stay inside it for too long.

Then how long can you survive?

Assuming your room is 10x10x10 ft

Volume of air in such room will be
28,300 litres of air

It is a fact that oygen is 20% of the total air.

Oxygen in room = 0.2 x 28,300
=5,660 ltr

On average we consume 550 ltr of oxygen on daily basis.

5660/550 = 10.2 days

You can live atmost 10 days before all oxygen is used up.

But that is not true in real world.

Room oxygen level from 19.5-23.5% is considered safe. At 14-16% it becomes hazardous. At 6% one can die.

Also the bigger problem to see is carbon dioxide buildup which will arise faster than decreasing oxygen levels.

We breath oxygen in and give carbon dioxide out.

The problem of excess CO2 occurs before the problem of lacking oxygen.

Let’s again calculate how long we have before CO2 levels become hazardous assuming room of 10x10x10 ft.

Fact: Co2 level above 5000 ppm can cause headache, dizziness, nausea. At 40,000 ppm one can suffocate to death.

141 litre of CO2 will start to cause headaches, dizziness, nausea.

141/550 = 6.1 hrs

One has 6 hours before he start to develop headache, diziness from co2 buildup in a closed room.

Calculation for above
volume of air
1000×28.3169 = 28,316.9 ltr

volume of co2 in the same room if its ppm is 5000.
5000 ppm = 0.5 %
(0.5/100) x 28,316.9 = 141.58 ltr of co2

Initially the co2 level is nearly zero.

How long you can live befor co2 crosses 5000ppm
141.58/550 = 0.25 days
= 6 hours

I will like to share one incident where a family was suffocated to death in a small bathroom.

In 2016 there was this robbery turned to murder case in Jakarta Indonesia , where the robber locked out 11 people in 1.5 m x 1.5 m bath room , after 17 hours 6 out of 11 hostages died from lack of oxygen or to say buildup of carbon dioxide.

The problem here was that there were too many people inside a very small space which was almost airtight.

How to maintain oxygen level in AC Room

With window and split AC, you will have to take some measures to ensure that some fresh air from outside enters your room.

  • You can open a window slightly.
  • Open the door slightly.
  • You can use indoor plants like the money plant.
  • Use exhaust fans.

However do not open the window too much as it will also bring heat from outside and put more load on the AC increasing the electriity bills.

Also note that in the night time plants produce carbon dioxide so either put the plants outside in night time.

Further you can also introduce a fresh air system in the air conditioned room.

For spaces like office buildings, factories, hospitals there is no need to worry as the HVAC systems used there can handle the oxygen problem.

Can I monitor oxygen levels in my room

If you are concerned about oxygen levels of your room that yes one can use an oxygen monitor.

This device can monitor the o2 levels but this device is out from the budget of many.

Instead you can buy an oxymeter to check your blood oxygen level.

According to the department of health, oxygen level (Spo2) of 95-100% is normal. Below that is sign of an underlying disease and one should seek advise from a health care provider.


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