Indoor climate

The indoor climate has an important influence on our well-being, comfort and productivity

A long article recently appeared in the FD about ventilation. It was mentioned in this article that in the west we spend about 90% of our time indoors (or at school or office). Research shows that a poor indoor climate is often the cause of common health complaints such as fatigue, headaches, and dry or irritated eyes. Other studies say that a good indoor climate can improve employee productivity by as much as 11%.

Indoor climate consists of many different parts which can be classified in 4 factors


Due to the focus on energy saving and insulation, the quality of the indoor air in the buildings where we live has often deteriorated. Where drafty houses provided natural ventilation, this now requires smart automatic ventilation systems. In practice we notice that the quality of the automatic ventilation systems

Humidity and Temperature

Due to the ever better insulation, it is increasingly possible to guarantee a comfortable temperature everywhere. Measuring and controlling indoor temperature is now quite well organized in most buildings. Humidity is more difficult and especially in winter a problem due to the dry air. High humidity breeds fungi, low humidity causes physical discomfort, and is associated with an additional risk of Covid contamination because in dry air the emitted droplets remain smaller and can therefore move further. Ventilation, automatic humidifiers, but also plants, can help to improve the humidity in buildings and make them healthier.


Volatile Organic Compounds (VOCs) are a fairly diverse group of volatile gases that are mainly associated with building materials in new construction, but also with new materials in existing construction such as floor coverings, furniture, appliances and other equipment. Printers can also emit Ozone which falls under this group of gases. Excessive concentrations of VOCs can affect well-being and productivity and cause headaches and dizziness. Non-specialist indoor climate sensors measure VOCs and display them in an overall Air Quality Index (AQI). The total level of this family of indoor air pollution is thus clearly displayed, but the individual gases are not broken down at these meters. Nevertheless, a general AQI makes an important contribution to monitoring the indoor climate. If the AQI numbers turn red on the meter, better ventilation is required.

Particulate Matter

Particulate matter is classified by size. PM2.5 then refers to particulate matter with a size of 2.5 microns, and PM10 to particulate matter with a size of 10 microns. In our country, particulate matter is mainly caused by traffic, agriculture and industry. Nature also contributes to particulate matter through volcanic eruptions, erosion and blown in desert sand, but also through pollen from flowers. Particulate matter has long been known as one of the most dangerous components of bad air. The smallest particles in particular can penetrate deep into the lungs and cause damage there to the lungs but also to other crucial internal body functions. In the case of dirty outside air, unfiltered ventilation through open windows is not recommended. Good ventilation systems have good filters that capture the particulate matter. In addition, there are mobile air purifiers that can effectively reduce particulate matter in the indoor air.


Optimal monitoring and regulation of the indoor climate must therefore take all these factors into account. Due to the coronavirus, good ventilation has suddenly become a top priority in all public spaces, including education, healthcare, catering and gyms. However the ventilation is arranged, with open windows or with complex ventilation systems, the urgent advice is to continuously measure and monitor the air quality in every room via easily installed CO2 meters.

Measuring is important to enable the responsible person (usually the teacher or other responsible person), who is on site, to intervene immediately and adequately based on objective measured values. With green, the air quality is good, with yellow it is moderate and ventilation is allowed, with red the students or other people present must leave the room and/or the ventilation at maximum (all windows and doors open). Due to the clear indication on the meter, there is neither too much (energy loss) nor too little ventilation.

Managing air quality is the ultimate goal of measurement. Measuring helps to intervene adequately on site by manually controlling the ventilation. In larger environments, easy-to-place solutions are being looked at to improve the air in those cases where open windows (think of winter) are no longer a solution. There are excellent air handling systems on the market that can be easily installed and moved.

The right combination of smart CO2 meters with an easy-to-read display (see Building Decree), built-in mechanical ventilation, mobile air purifiers (particularly for VOC, particulate matter) and humidifiers is necessary to optimally optimize the 4 factors of the indoor climate. monitor and improve.