Ventilation and indoor climate

1. A building has to be able to breathe

Tightened building regulations mean that renovation projects and new builds are extremely airtight – so airtight, in fact, that it almost feels like being in a bag. Buildings must be airtight – and yet able to breathe. This might sound contradictory, but what it actually means is that buildings must be airtight to keep the energy used on heating to a minimum. Buildings must be able to breathe so that moist, “stale” air can escape. They should not breathe through random gaps, but via controlled and demand-controlled ventilation.



Moisture and mould

A typical consequence of inadequate ventilation is that the relative humidity increases, with the possibility of mould forming in the building as a result. Substances that are harmful to humans and animals are found in mould spores.

What should you do?

You need to air out – but in the right way. Decentralised ventilation with heat recovery ensures that nothing is left to chance. A decentralised ventilation unit, which automatically adjusts the supply of fresh air to each room, ensures an economically sound indoor climate.

2. Healthy indoor climate

Our health is at stake

Not all buildings have a good indoor climate, and this is often due to the fact that there is too much moisture in the building at the same time as a high level of off-gassing and little or no ventilation. This can have both health and financial implications.

For the building, it can mean dry rot and fungus in the structures, which ultimately may destroy the building – and the consequences for occupants can be asthma and allergies if it is allowed to develop.

An increasing number of people are being diagnosed with asthma and allergies, and part of the cause is a poor indoor climate.

Did you know that...

  • High CO2 levels, a high room temperature and high humidity = a poor indoor climate.


  • The air inside is full of chemicals and particles emitted by furniture, flooring, electronics and painted surfaces, etc. Airborne chemicals and particles attach themselves to dust.


  • Typical signs of high humidity are steamed-up windows, damp patches on ceilings and/or walls, bulging wallpaper that is coming away from the wall, drawers and doors that stick, and last but not least, mould.

An everyday example

The result is clear. Without ventilation, the CO2 level rises to 2000 ppm in the space of a single lesson.

Considering how many hours we spend in day-care, educational institutions and at work, this result is both thought provoking and disturbing.


CO2 readings taken in a traditional classroom at Gl. Hasseris School clearly show how crucial good ventilation is to air quality. The blue line shows the CO2 level with an Airmaster unit in operation. The red line shows readings taken in the same room without ventilation.

CO2 measurement in school

CO2 readings over a week

CO2 levels and their effect

400 - 1000 ppm

At 400–1000 ppm, the CO2 level is normal in a room with a good supply of fresh air.

1000 - 2000 ppm

At 1000–2000 ppm, you will typically feel sleepy and have difficulty concentrating.

2000 - 5000 ppm

At 2000–5000 ppm, you will typically have a headache and feel sleepy and generally uncomfortable.

5000- ppm

At 5000 ppm or more, there is a risk of passing out due to CO2 poisoning.

why ventilation is important!

3. We need to save energy

Not only must we create a good indoor climate for ourselves and for the building, but we must also save energy. Energy savings are usually part of renovation projects in particular, where older building stock is renewed and modernised. This is where Airmaster decentralised ventilation comes in – operating costs for electricity are extremely low and, what’s more, the demand control will ensure that only the rooms that need it are ventilated. 

energy calculator

Energy calculator

Using the “energy calculator”, you can calculate the annual energy consumption of the Airmaster ventilation unit

Ready for a breath of fresh air

At Airmaster, we are “decentral” through and through. We are unrivalled when it comes to creating the best indoor climate and optimal well-being because we take each room and its occupants into account – and because we constantly strive to improve on what we do.