Tiredness, sleepiness, apathy, headache, annoyance and inability to focus. Sounds familiar? The reason is simple and the cause is very easy to eliminate — high level of CO2 in the room.

Yes, that’s what it is.

If we feel unwell we go to a lot of doctors, get tested, take vitamins and have expensive medical examinations. But we forget that our environment is as important as the quality of our sleep, food and lifestyle.

The impact of CO2: One person’s case

Anton’s (not the person’s real name) personal analyst was trying to find the cause of a peculiar situation: for three days Anton’s energy level was 30% lower than usual. The analyst noticed a rise in CO2 level in Anton’s bedroom the day before the loss of energy (the data was obtained by Withings smart scale). The answer was simple, Anton and his girlfriend had the doors and windows in the bedroom shut when they were having sex. Anton’s body got so intoxicated that it took him three days to recover.

PICTURE: 3 times the normal level for 4 hours
Air quality
Monday, 11 July 2016
Temperature (°C)
CO2 level

What are the risks of not having fresh air at home?

Even if you have an active lifestyle and busy work schedule, you still spend 30% of your time at home.

Sleeping doesn’t properly recover the body if the CO2 level in the room is high. Even if you sleep for 8-9 hours, the quality is more important than the amount. Closed windows are the cause of being annoyed and tired in the morning.

lack of sleep

If you regularly experience a lack sleep try keeping the window open at night.

CO2 impact

  • It’s hard to fall asleep, you suffer from insomnia
  • You can’t remember what dreams you had or remember only the short ones
  • You feel tired in the morning regardless of how much sleep you had
  • Coffee makes you annoyed rather than perks you up
  • You don’t want to move, you are apathetic and lazy and sometimes depressed
  • Stuffy nose, sore throat, dry cough and headache

In 55% of cases the quality of our users’ sleep improves by at least 30% when we recommend them to simply leave the window open at night. The brain works more efficiently. The body is in a better condition. People feel more productive at work and less tired in the evening.

At the office: lower productivity

We spend 8 hours a day at work, sometimes even 10 or 14. If you are not a beach lifeguard or Richard Branson working on your personal island, then what do you do? Right, the air most of us breath is of poor quality.

Give this list of CO2 poisoning symptons to everyone who asks you to close the window

  • It’s hard to focus
  • Poor attention, it’s hard to memorise information
  • Overall productivity is low
  • No energy, yawning, sleepiness
  • It is hard to do something new or creative, you can do only routine work
  • No desire to go anywhere after work, enough energy only to get home

Middlesex University (UK) conducted a study with 300 workers. It found that the normal level of CO2 at workplaces should be 600-800 ppm. If it is higher, it is 30% harder to concentrate. 79% of respondents said they felt tired at 1500 ppm.  65% said they could not concentrate at 2000 ppm. If you are a CEO and your staff don’t work well, maybe the problem isn’t their laziness?

Offices often use air conditioning with all windows and doors closed. People think that split systems deliver oxygen from outside. But it’s not true. These systems use halocarbon refrigerants and fresh air doesn’t flow into the room. At all.

As a result, CO2 level in the air people breath rises every hour. It can get to 2500 ppm by afternoon, but we don’t feel the lack of oxygen.

CO2 poisoning can go unnoticed, just like carbon monoxide poisoning.

Carbon dioxide: when is it dangerous?

We spend most of our time indoors with no fresh air.

Even if we have a walk in the evening it won’t help us get rid of the consequences. You can’t store the air your breath “for future use.” No matter where you are, at home, at the gym or in your car, air quality seamlessly and constantly affects your health.

CO2 is necessary for the body to stay healthy. However, there may be serious harmful effects on your health if CO2 levels are regularly and significantly high.

CO2 concentration is measured in ppm (parts per million).

  • The perfect level for the human body is 450-600 ppm. You get that kind of fresh air outside in the city.
  • The norm is 600-1000 ppm. If it goes over that you get first symptoms: yawning and sleepiness.
  • We usually notice that it’s becoming hot when the concencration is already over 2000 ppm.

CO2 level (ppm)
Over 1000
Over 2000
Ideal for people’s health
Adequate air quality
Recommended for children’s rooms, bedrooms, offices, schools and kindergartens.
Poor air quality is noticible. People with asthma may have attacks.
Overall discomfort, lack of energy, headache. Concentration is 1/3 lower. Number of errors grows. There may be negative effects on the blood. There may be problems with the respiratory and vascular systems.
The amount of errors is very high. 70% of workers can not concentrate on their work.

Everyone’s sensitivity level is different, it depends on the overall state of health and other lifestyle factors. For instance, children are more sensitive than adults. Frequent colds, weakened immune system, cough and running nose, all that can be a sign of lack of fresh air.

How to measure the CO2 level

There are different devices which notify you when you should ventilate the room in advance. They also help you settle the never ending conflict between those who are cold and those who are hot. You will have an objective argument: we won’t be able to stay efficient unless we ventilate the open space at the office.

Netatmo Weather Station

Price: 11 000 – 16 000 rub


It measures temperature inside and outside, CO2 level and air humidity.

Netatmo Weather Station notifies you when it’s time to ventilate the room. It’s simple, you can get notifications on any of your devices. Everything in real-time mode.

Besides, Netatmo just looks cool. Buy.

Foobot Air Quality Monitor


Price: $145-199

It detects formaldehyde, benzene, xylene, toluene and particulates in the air. It also measures temperature, humidity, CO2 and CO levels.

Put it by your fireplace or gas stove and it will warn you in advance. You can see the quality of the air in the app on your smartphone and take necessary measures.

Foobot won’t let you get poisoned by carbon monoxide. Buy.

Withings Smart Scale


10 800 – 14 000 rub

The scale can do so many things that it will be useful in any home. It measures your weight, fat mass and pulse as well as air quality and CO2 levels.

It will show you the temperature inside and outside (using weather forecast services in your region).

It synchronizes with many apps, so now it has become easier to achieve your goals and lose weight.

Withings Scale will also let you know when you need an umbrella. Buy.

How to keep the ideal CO2 level at home and at work

You’ve measured the CO2 level. Yes, it’s high. So what do you do?

There are various ways to solve this problem.

1. Ventilate your room regularly and leave the window open at night

Difficulty: easy and free

It’s a perfect solution if it’s summer outside. However, we prefer to close windows if it’s winter. By the way, have you noticed that it is in winter that many people have “seasonal affective disorder”?

You can’t keep rooms ventilated if you have vinyl windows. Ventilating before going to bed won’t do much, because in a couple of ours the air will no longer be fresh.

Trickle ventilation provides weak fresh air intake which may be insufficient. But it’s better than nothing.

2. Check your ventilation system at home and at the office

Difficulty: hard, but should be free

Hold a burning match in front of a ventilation vent, if the fire doesn’t lean toward the vent then the ventilation system doesn’t provide enough airflow. Try opening the window to create draught. Nothing changed? Then the ventilation system isn’t working properly.

Call your facility management company, they are responsible for the ventilation system and its repair. However, people often block ventilation vents which is why it can be hard to solve the problem, you’ll need to write to various local authorities.

Offices often change the original floor plans, but moving to a different place only because of that is not an option.

3. Install a trickle vent

Difficulty: fairly easy, different prices, won’t spoil the interior design

The easiest option is to install a trickle vent between the window sill and heater. This way winter air flowing into the room will be warm.

There are different types of vents, for example, they can be installed in vinyl windows.

4. Install a supply ventilation system with air heating

Difficulty: you will have to call a professional installer, it’s expensive but very effective

It is an ideal option if you need an out-of-the-box solution. It maintains adequate air quality, cleans the air and heats it up in winter.

It’s great for homes and offices. It is worth it. Ventilation is seamless without any sharp temperature drops or increases, and it’s noiseless as well. It doesn’t create draughts, it’s safe for kids or workers that are constantly ill.

Tion seamlessly provides everyone with clean air


Price: Starting from 21 300 rub

Here is a good review: https://geektimes.ru/company/tion/blog/264912/

Buy: tion.ru

Simple rules for feeling well

  • If you are cooking – ventilate!
  • If you use an air conditioner? Don’t close the window, let fresh air in.
  • If you get sick frequently and are tired of headaches – ventilate!
  • If your windows are equipped with insulated glazing units install a supply ventilation system.
  • If there are many people in the room open the window for at least 5-10 minutes every hour.
  • Use a CO2 sensor to ventilate the room when needed.
  • If you smoke a lot and suffer from migraines or asthma make sure the CO2 level stays low.

To sum up

The good news is: a simple way to get rid of chronic fatigue is to leave the window open at night.

The bad news is: air quality isn’t always the cause of these symptoms.

But you can always experiment and ventilate your room. You will definitely notice a difference in your wellbeing and the quality of your sleep.

Want to do it with objective data? Download Welltory %)

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