Why does the SKYEN only visualize CO2?

The CLOUD only visualizes the CO2 level in the room, as this is the best parameter for assessing the indoor climate in a room.

The more people staying in the room, the higher the humidity, noise, temperature and CO2 level will be.

However, it is not certain that you can lower the humidity or the temperature in the room by venting, as it depends on the season and the weather outside. On a rainy day, it can be difficult to reduce the humidity. On a summer day, it can be difficult to cool the room down by venting.

Since the CO2 level outside is always approx. 450 ppm. (regardless of the season or geography), you can always be sure to reduce the CO2 level in the room with simple ventilation with drafts.

The CO2 level is what affects the cognitive functions and is therefore seen as the biggest culprit for reduced performance and risk of asthma. The CO2 level is therefore also the most accurate and reliable to measure, as we can use a baseline, namely the outdoor air. Overnight, the CO2 level will in most cases drop to the same level as outside, i.e. 450 ppm.

Where should I place the CLOUD?

The CLOUD should be located in a central place in the room, where it is visible and provides representative CO2 measurements. Often it gives itself. This could be next to the blackboard in the classroom or on the back wall of the office.

The most important thing is that it is not placed right next to a window, as SKYEN will then think that the indoor climate in the room is good, even if it has only been ventilated briefly with drafts for one minute. Preferably place it somewhere with two openings on either side of the room.

How do I set up the CLOUD?

See our short video guide for setup .

How many CLOUDS do I need?

As a starting point, you only need one SKY per 200 square meters.
However, this can vary according to the possibilities for drafts or air circulation in the room.

Feel free to contact us via chat, email or phone. We are happy to estimate how many CLOUDS you need in the room, based on the possibility of changing the air in the room.

When does the CLOUD change to red?

The CLOUD changes to red at 1000 ppm. This is a value set by the Norwegian Working Environment Authority, as it is here that the indoor climate starts to become harmful over time.

When does the CLOUD change back to blue?

The CLOUD changes back to blue at 800 ppm.

Is the SKYEN available with a battery?

No. We have chosen NOT to have batteries in the CLOUD for sustainability and practical reasons. SKYEN is built to be set up in many rooms and therefore requires a minimum of maintenance and operating costs. When the CLOUD is plugged in, we can ensure that the CLOUD does not go out and thus lose its value, as well as save you costs for batteries and replacing/charging them.

More and more municipalities are also beginning to require that electronics must be wired. Therefore, check your own rules before you buy equipment with a battery.

What is the size of the CLOUD?

THE CLOUD is the size of an adult's hand:

  • SKYEN's width: 143 mm
  • Height of the CLOUD: 83 mm

    The SKYEN therefore fits on any wall or shelf without taking up too much space.

Delivery and trading conditions

How is my package delivered?

All our products are packed securely and sent with GLS directly to your company.

If you are a private customer, you can have your parcel sent to the nearest GLS delivery point.

It is also possible to pick up your goods at Jernholmen 2, 2650 Hvidovre. Contact us to make an appointment for collection.

What is the delivery price?

Shipping costs DKK 80 per item as standard. delivery regardless of size.

What's the delivery time?

The package is generally delivered within 2-3 working days. Delays may occur.

How do I track my package?

You will receive a tracking number via email when the package is dispatched. If you have problems finding your tracking number, feel free to contact us at

Where do I see the terms and conditions?

Delivery abroad

For delivery abroad, contact us at or telephone +45 4013 0705.

Can I cancel and/or return an order?

You have a 14-day right of return and cancellation. To make use of the right of return and cancellation, you must notify us of this within 14 days of receiving the item.

You can contact us on tel. 40130705 or You will then receive a return form by email. When we have received the item, we check it and refund the amount you paid for the purchase (including delivery costs). Returned goods are processed no later than 14 days after receipt.

Do I have a warranty?

All manufactured units are guaranteed for a period of 12 months from delivery. The warranty covers manufacturing defects and component defects.

SKYEN has been tested by the Danish Technological Institute, which has documented a 7-year accuracy guarantee.

Indoor climate

What is CO2?

CO2 stands for carbon dioxide, which is a colorless and odorless gas. It is a carbon compound that is formed during combustion, including the combustion that takes place in the body, which is also called our metabolism. CO2 plays a significant role in the earth's climate system, as it can contribute to the greenhouse effect and thus affect the temperature on earth. While CO2 is a natural part of the atmosphere, elevated levels of CO2 in enclosed spaces, such as schools and offices, can adversely affect the indoor climate and have a detrimental effect on the health and well-being of those occupying the space.

Why reduce CO2?

Reducing CO2 in the indoor climate can have several advantages, including:

  • Improved health: Elevated levels of CO2 can lead to headaches, fatigue, eye and breathing irritation, and even reduced cognitive function. Reducing CO2 can therefore improve health and thereby increase the well-being and productivity of those staying in the room.

  • Increased performance: Reducing CO2 can improve performance on tasks that require concentration and attention, which are important for both students and employees in workplaces. This can increase efficiency and performance in the workplace.

  • Improved indoor air quality: By reducing CO2, you can reduce the risk of indoor air pollution that can arise from other sources such as paint, household chemicals and cleaning products. This can also result in reduction of allergies, asthma and other respiratory problems.

How can I measure CO2?

If you want to measure the CO2 level in your indoor climate, there are several methods you can use. Pay particular attention to:

  1. That the sensor measures CO2. Many cheap sensors only measure humidity and temperature or have an "environmental sensor". You can easily be tricked into thinking that you have bought a CO2 sensor, even though you have actually just bought a thermometer.
  2. That the sensor is documented. If you have found a CO2 meter, be sure that it has been tested by an impartial third party. A great many sensors on the market are imprecise and downright useless for indicating the CO2 level.

One of the most effective methods is to use a CO2 meter, such as THE CLOUD from OPEN. SKYEN is a simple and reliable device that measures the CO2 level and gives you precise measurements.

The market for indoor climate meters has exploded, so it is important that you find a reliable supplier of your CO2 meter. The sensor in SKYEN from ÅBN is a genuine CO2 sensor which has been thoroughly tested by the Norwegian Technological Institute.

You can find the report here:

How can I easily reduce the CO2 level?

Here are some simple methods to reduce CO2 levels indoors:

  1. Open windows: Allow for fresh air by opening windows and doors. Create drafts if possible. It will help to ventilate the room and reduce CO2 levels.
  2. Use CO2 sensors: CO2 sensors monitor the level of CO2 in the room and will alert you when the levels get too high. With SKYEN you can see when the CO2 level is too high - SKYEN will light up red.
  3. Regular HVAC System Maintenance: Have your heating, ventilation and air conditioning (HVAC) system checked regularly to ensure it is running optimally and that CO2 levels remain low.

Is there a health risk with high CO2 levels?

If the CO2 level in a room exceeds 1,000 ppm (parts per million), it can lead to a number of symptoms such as headaches, fatigue, reduced cognitive function, increased blood pressure and irritation of the eyes and respiratory system.

If the level reaches 5,000 ppm, it can lead to more serious symptoms such as dizziness, nausea and even fainting. Therefore, it is important to monitor and reduce CO2 levels in indoor spaces to ensure healthy indoor air quality.

In 2018, the World Green Building Council published a report showing that a healthier working environment can reduce sickness absence by 58% - equivalent to four days per year. employee per year.

A team of English researchers has documented that optimal ventilation provides a reduction in the relative risk of COVID-19 infection by more than 70%. Therefore, many countries, including our own, have recognized ventilation as a special weapon in the fight against viruses.

What is "Sick Building Syndrome"?

Sick Building Syndrome (SBS) is a condition that describes a range of symptoms such as headaches, dizziness, fatigue and breathing problems that can be experienced when staying in a particular building. Symptoms appear to be related to the length of time one has been in the building and tend to disappear after leaving the building.

SBS can be caused by various factors such as poor indoor air quality, inadequate ventilation, high levels of CO2 and other pollutants, increased humidity and poor lighting. In addition, the presence of allergens such as dust, mold and bacteria can cause irritation of the respiratory tract and trigger asthma or allergic reactions.

Can you get sick from drafts?

No. Traits by themselves usually do not cause disease. Infectious diseases spread between people, so if you are isolated, such as on the Greenland ice sheet, you would not catch a cold or the flu, as there is no one to infect you.

Nevertheless, drafts can increase the risk of diseases developing. When a person is exposed to cooling, drafts or cold air, the blood in the body is drawn away from the skin and mucous membranes to protect the internal organs. This can lead to a reduction in the effectiveness of the immune system in the mucous membranes.

However, it must be emphasized that drafts do not usually cause serious illnesses unless they lead to a permanent or prolonged cooling.

About OPEN

Who is behind ÅBN?

Can you buy online?

Of course!

SKYEN and all our other products can be purchased directly on this page. You can find all our products here.

Still in doubt? Contact us!