
Hand-Held Humidity and Temperature Meter HM40
for quick inspections and spot-checking
Technical note
This year, Vaisala celebrates a significant milestone in its history: the 50th anniversary of the HUMICAP technology. Since its development in 1973 by Tuomo Suntola, HUMICAP has become the standard for humidity measurements in various industries worldwide.
The solution was first implemented in weather stations, then in radiosondes, and after that in industrial measurement devices. Currently, Vaisala produces the sixth generation of HUMICAP. From the outside, it looks very similar, but all the materials and manufacturing processes have changed several times over.
HUMICAP's reliability and precision have made it a foundational element of industrial measurements. It has allowed Vaisala to advance in its field and achieve the success it has today. This demonstrates how innovative Vaisala has been with the technology.
Vaisala has become the market leader in relative humidity measurements, and thin-film capacitive humidity sensors have developed from being the innovation of one company to a global standard. HUMICAP – the tiny giant – has earned its name.
“HUMICAP itself is an important technology for us. We are proud of the way Vaisala has continued to develop and improve HUMICAP over the years. DRYCAP® and PEROXCAP®, which use the same basic technology developed based on HUMICAP, have become widely used in various industries, from manufacturing to healthcare. These are great examples of learnings for developing new technologies”, said Lars Stormbom, Senior Product Manager, Industrial Measurements, Vaisala.
“Humidity affects numerous processes and situations. Thus, there is a huge number of applications for HUMICAP, particularly in cases where the humidity conditions need to be very precisely managed. In addition to radiosondes and weather stations, HUMICAP sensors are used, for example, in temperature and process measurements, life science, and semiconductor industry,” Lars continued.
The work was ordered in 1971 by Yrjö Toivola, Vaisala’s Managing Director at the time. The purpose was to investigate the technologies that were used to measure relative humidity in the atmosphere with the aim of incorporating the humidity sensor to Vaisala’s ground weather stations, and with the dream of also adding the sensor to a sonde. Toivola ordered the work from the Technical Research Center of Finland (VTT), where Suntola at the time was finishing his doctoral thesis.
The biggest innovation was applying a polymer a thin film structure, which was completely new and revolutionized the whole humidity measurement industry and suited the sonde very well. From the production point of view, the technology was cutting-edge: the process is mass production friendly, and the sensor is so linear that it enables us to have only two a few calibration points.
As Vaisala celebrate the 50th anniversary of HUMICAP technology, we stay true to our values and embrace pioneering innovation. We look forward to seeing what the next 50 years will bring and are excited to continue leading the way in the industrial measurements industry.

for quick inspections and spot-checking

For high precision measurements in demanding HVAC applications

for environmental chambers

with ±1.5%RH accuracy for demanding volume applications

with ±1.5%RH accuracy for demanding volume applications

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