What is good indoor climate?

People want to live and work in a healthy and sustainable environment with a good indoor environment throughout their lives.

Indoor climate — From past to present

The indoor climate in buildings impacts people's health, comfort, well-being, productivity and performance. A poor indoor climate can have short- and long-term health effects, such as health disorders, respiratory diseases, high-stress levels, and people's discomfort. Indoor climate considerations can enhance the building's quality, energy efficiency and sustainability through an integrated design approach.

However, the above statements are all about today. But the indoor climate has been here forever. It was just not so much visible — it is the invisible air, right? — and the problems were not so much visible either. In the past, indoor air has always been polluted by human activities indoors, be it cooking or burning wood. Today, we are facing another set of problems in connection with getting the right amount of clean air to our & from our buildings, either by ventilation or other means.

Many forces have driven indoor air science. One driver is the demand to fix important indoor air problems arising from various pollutants: radon, particles, volatile organic compounds, mould, bacteria, and associated health effects, e.g., sick building syndrome symptoms, asthma and allergies, and airborne infections. The second driver is the new technologies such as advanced mechanical ventilation and other building systems, data monitoring & data analysis and human activities, which have contributed greatly to modern indoor air science. And by understanding the historical influences on the development of indoor air climate over the past decades, we can also perceive its future.


Find out more about indoor climate — From past to present

"Besides addressing thermal comfort and other IEQ issues, buildings and other enclosed spaces are increasingly challenged to provide a healthy environment in an energy efficient manner. The complex relationship between indoor and outdoor environmental conditions, coupled with the impacts of climate change, requires a paradigm shift towards creating buildings that are comfortable and healthy for the occupants yet also energy efficient. Although the goal of improved IAQ and thermal comfort can be achieved by increasing energy consumption, it can also be achieved without significant increase or even with decreased energy consumption."

— ASHRAE IAQ, 2013

Understanding the elements of indoor climate

When describing the indoor climate, we often use the term of the environmental quality (IEQ). IEQ can be defined and determined by a variety of physical and psychological aspects of the indoor climate which can affect our health, well-being and performance — including, but not limited to, such as air quality, thermal comfort, light quality and acoustic conditions, as well as others.

Air & indoor air quality — Research suggests that the concentration of pollutants can be up to five times higher indoors than it is outside. Common sources of indoor air pollution can include pollutants infiltrating from the outdoor environment, building materials and furnishings as well as animals, etc. Some indoor pollutants which can have adverse effects on people, their health, well-being and performance.

Temperature & thermal comfort — Thermal comfort refers to the subjective experience of feeling satisfied with one’s thermal condition. The air temperature (including air temperature distribution, etc.) and other factors influencing thermal comfort include humidity (including absolute and relative humidity) and air velocity (e.g. if there is a draft). The thermal environment is important for our comfort and our health.

Light & light quality — Light and lighting indoors (natural daylight and artificial lighting in buildings) plays an important visual function for people. Our bodies are naturally programmed to function on a cycle that is primarily set by daylight also known as the circadian rhythm. Getting the right light at the right time helps to regulate many functions of our body, including the sleep-wake cycle, mood and metabolism.

Acoustics & sound quality — While overlooked in most discussions of environmental quality, acoustical conditions and sound levels are important. Sound enables us to hear the world around us, but it can be unwanted or even harmfull, i.e. so called noise. Sound pollution and various types of noise in the daily environment can also critically impact individuals comfort and wellbeing in a given space.


Read more about the elements of indoor climate

Indoor environmental quality

How it all began? And what is the big picture for indoor environmental quality? Throughout history, man understood that polluted air could be harmful to health and that the indoor air is a dominant exposure for humans. For more than a hundred years, indoor air was believed to be a major environmental factor until also outdoor environmental issues have became dominant.

Indoor environmental quality (IEQ) is more complex than indoor air quality (IAQ). There are many key similarities of IEQ and IAQ. One similarity between indoor air quality and indoor environmental quality is that both are influenced by the design, construction and maintenance of a building. For example, efficient ventilation and air filtration systems can help to maintain good indoor air quality, while well-designed lighting and acoustic systems can contribute to overall indoor enviromental quality.

Another similarity is that the building occupants' activities can be affected by indoor air quality and indoor environmental quality. For example, cooking and cleaning can all release various pollutants into the air, which can negatively affect indoor air quality. In addition, the choice of furniture, flooring and lighting can all affect indoor environmental quality.

Transitioning from just indoor air quality with building's energy efficiency to the complexity of indoor environmetal quality and people's health. By using an automated monitoring system, the indoor climate in buildings can improve employee wellbeing, comfort, and productivity, all whilst saving on energy costs and reducing your carbon footprint. Monitoring IEQ parameters in the spaces can help identify issues and select appropriate interventions.


Discover why indoor environmental quality is so complex
Our environmental preferences are based on value judgments which are learned through past experiences and influenced by our background and social-economic level and age is an important catalyst.
F. Rohles, Jr., Ph.D.