Provide, control and reduce

We spend 100% of our time breathing air, so we need to have the best possible indoor air environment at all times. So we need to provide good indoor environment, via controlling air quality and reducing harmful pollutants indoors.


  • When we want to create a comfortable, healthy and safe environment for people — in homes, offices, schools, and other environments.
  • When we want to improve productivity of employees in office buildings and performance of students in schools.
  • When we want to reduce sick time, i.e. sick days at offices and absenteeism in schools.


  • When we want to enhance comfort for the buildings' occupants, i.e. control temperature, humidity and other parameters of the indoor environment.
  • When we want to control occupants exposure to air contaminants, i.e. remove or dilute airborne contaminants.
  • When we want to ensure energy-efficient and sustainable operation of a building and also regulated costs, i.e. investment, operating and maintenance costs.


Fresh air comes into buildings where it then gets recirculated, used and polluted by various sources. Indoor air can build up high levels of pollutants from people's activity or building materials. 

Our indoor air gets polluted by:

  1. People's activity (and also animals) — carbon dioxide (CO2), moisture or odours, etc.
  2. Building's materials/technology and equipment — furniture, floorings (VOCs as volatile organic compounds that are carbon-based compounds that easily evaporate).
  3. Outside pollutants from traffic and earth — CO or radon from the ground, etc.

Special examples of when we need to ventilate

  • When the outdoor climate is more extreme, for example in cold climates or hot/humid climates.
  • When close proximity creates problems, i.e. to other outdoor conditions surrounding the buildings such as noise from traffic, location near polluting industries or seasonal issues with dust and pollen.
  • When we want to avoid heat build-up in more demanding time periods in a year, such as hot spells during summer. 
  • When the building envelope is too airtight and sealed: this is especially true for new built buildings and/or renovated buildings.
  • When we need to maintain specific conditions due to the purpose of a building, i.e. hospitals and laboratories.

The importance of ventilation

The main reasons for ventilation are all about people ⁠— ventilation is for us and about us. Ventilation is not just about air — heating/cooling it and exchanging it and get it clean.

Scientific research also shows that ventilation is not only about 'window opening' or 'fresh air from the outside'. But its most importance is to dealing with the notion of creating 'a good indoor environment'.

Who needs ventilation?

Simple answer is everybody — we all do need ventilation. Ventilation is important for everyone — from the basic physiological need for air, bringing positive impact on people's health & wellbeing and to creating a healthy environment for all.

Where the ventilation is needed?

Of course, ventilation is needed everywhere indoors — in people's homes, at various workplaces & educational facilities, at other activity-based spaces such as shopping malls, hotels, restaurants and everywhere else.

And the ventilation is also needed in cars, airplanes and seaships, and many more spaces. As in there there are also ventilation systems that help control air quality and air circulation.

And one of the most dependent on ventilation are the closed structures located in spaces without the natural occurance of air (and also many other substances) — submarines and spaceships.

Dealing with ventilation

Who and how is affected by ventilation?

Interaction with ventilation, degree of control and effects of ventilation

Who is dealing with ventilation?

Building occupants, owners, manufacturer...

Occupants interactions with ventilation

Occupant impact on ventilation, i.e. how occupants react to and/or are affected by the indoor environment

All about occupants´ perception about ventilation and indoor climate in the buildings they live/sleep, work and leisure.

The degree of control

A key consideration is the degree of control that occupants have over the indoor environment. This very much depends on the type of building and on the adequacy of control measures provided.

  • In single homes, the occupant has virtually total access to the various mechanisms available (heating, ventilation controls, window opening etc.).
  • On the other hand, in multi-storey dwellings, offices, shops, public buildings and industrial premises, direct control may not be available to occupants or, if accessible to individual users, they may influence the environment for adjacent occupants. Unless there exist more individual controlled environment - based on the zoning of the spaces/buildings or the demand controlled control systems, etc.

The effects of occupants interaction

Basically, it can be stated what are the effects of occupant interaction on several issues:

  • the influence that occupants have in controlling their environment
  • factors beyond the control of occupants
  • thermal comfort, and or draught
  • health, well-being and productivity
  • energy use and environmental impact

What we all can do, i.e. outdoor air quality control

The steps towards achieving good indoor environment starts with outdoor pollution, source control (via legislation), location of air intakes (design and guidelines), building location (proximity to pollution sources), envelope insulation and airtighness (legislation and guidelines), filtration of particles (i.e. starting with source control + air filters and so on).  And delivering clean supply air.

In essence these steps are primarily within the domain of legislation and requirements imposed on the designer and builder to ensure that the occupant is protected

"One of the challenges with ventilation is that people want a simple rule — but there isn't one. It's a specialist area and we need to recognise it in that way."

— Catherine Noakes, Professor of Environmental Engineering for Buildings, University of Leeds, United Kingdom


Want to read more about the air?

Download our book, AIR. The aim of the book is to provide insights into the factors and circumstances, including the outdoor environment, that significantly influence the creation of a good indoor climate and energy-efficient ventilation solutions.


Download AIR by Swegon Air Academy
Duncan: This castle hath a pleasant seat; the air nimbly and sweetly recommends itself unto our gentle senses.
William Shakespeare, Macbeth