Improving indoor air quality with CAREL’s new sensors

Clean air is a basic requirement of life: the quality of air inside homes, offices, schools, public buildings, health care facilities [...] is an essential determinant of healthy life and people’s well-being.

- WHO Guidelines for Indoor Air Quality – selected pollutants -


On average, we spend 90% of our lives in enclosed buildings

- A Resource for Assessing Exposure to Environmental Pollutants (2001) - 
- The National Human Activity Pattern Survey (NHAPS) -


30% of new and remodelled buildings may have an indoor air quality problems.

- United States Environmental Protection Agency (EPA) -


It’s now clear to everyone how important the quality of the air we breathe every day inside our homes and offices is.

Indeed, there is a strong correlation between the levels of various environmental parameters and our comfort and health. Keeping parameters such as temperature, relative humidity, CO2, VOC and PM within the optimal range improves comfort and productivity, drastically decreases the probability of transmission of airborne diseases, and strengthens the defences of our respiratory system.


Parameters for measuring IAQ


Temperature is a physical parameter that relates to sensations of heat and cold, and expresses the thermal energy of objects. For personal comfort, the indoor temperature should be between 67 and 82°F or 20 and 27°C throughout the year.


Relative humidity

Relative humidity is the ratio of the water vapour present in the air to the maximum amount that the same air can hold before it precipitates. The human body responds best in a relative humidity range between 40 and 60%.


CO2 concentration

Carbon dioxide is a colourless and odourless gas resulting from combustion and human respiration. It is naturally present in the air (0.03%) and is absorbed by plants through photosynthesis. It is often measured indoors as a marker of human occupancy, with high levels of CO2 requiring an increase in ventilation. The recommended values for indoor environments are below 1000 ppm.


VOC concentration

Volatile organic compounds (VOC) are the organic chemical components responsible for the presence of odours and certain pollutants. Indoor levels are usually much higher than outdoor levels, due to overuse of chemicals and detergents for cleaning. Prolonged exposure to these chemicals can cause irritation, headache and some may even be carcinogenic. The recommended values for indoor environments are below 300 ppb.


PM concentration

Particulate matter includes a set of solid and/or liquid particles suspended in the air, and generated by activities such as cooking, cigarette smoke and other sources of combustion, as well as printers. The finest particles are able to penetrate deep into the lungs. The recommended values for indoor environments are below 10 μg/m3 for PM2.5 and below 20 μg/m3 for PM10.


Hence CAREL’s commitment to introduce an upgraded range of air quality sensors on the market.

The new sensors are all equipped with serial communication to simplify installation and connection, and are available in wall-mounted or duct versions, with and without display. A 5-in-1 version is also available, which includes temperature, relative humidity, CO2, VOC and PM sensors in one single product, so as to improve aesthetics and reduce installation costs.

Discover the range of sensors


Whether a retrofit or an installation in a new building, correct management of indoor air quality is the next major challenge in the air conditioning industry, in parallel with energy efficiency. In addition to sensors, CAREL can also offer a complete solution for monitoring and controlling air quality.