Do you need to measure absolute humidity in temperatures up to 350°C (662°F)?

we have the right sensor for you

Measuring humidity in high-temperature processes is important for several reasons:

Product quality control: In many industrial processes, the presence of excessive or insufficient humidity can have a significant impact on the quality and characteristics of the end product. For example, in drying or curing processes, maintaining the right humidity level ensures proper moisture removal and prevents issues like cracking, warping, or uneven drying. By monitoring humidity, manufacturers can ensure consistent product quality and minimize defects.

Process optimization: Humidity levels can influence the efficiency and effectiveness of various high-temperature processes. By accurately measuring humidity, operators can optimize process parameters to achieve desired outcomes. For instance, in heat treatment or annealing processes, controlling humidity can impact the hardness, strength, and other properties of the treated materials.

Safety and equipment protection: Excess humidity in high-temperature environments can lead to corrosion, rust, or condensation on equipment surfaces. Monitoring humidity levels helps prevent such issues, protecting sensitive machinery, instruments, and components. Additionally, humidity control can minimize the risk of electrical shorts, insulation breakdown, or other failures that could pose safety hazards in industrial settings.

Energy efficiency: In some processes, maintaining specific humidity levels can contribute to energy efficiency. For example, in drying applications, excessive humidity can require extended processing times and higher energy consumption. By accurately measuring and controlling humidity, operators can optimize energy usage, reduce processing times, and improve overall efficiency.

Process stability and repeatability: High-temperature processes are often subject to variations in humidity levels, which can affect process stability and repeatability. By continuously monitoring humidity, operators can identify deviations from target values and make necessary adjustments to maintain process consistency. This ensures that the process operates within desired specifications and produces consistent results over time.

Environmental considerations: In certain industries, such as semiconductor manufacturing or pharmaceutical production, strict humidity control is necessary to maintain cleanroom conditions. Monitoring and controlling humidity levels help prevent contamination, ensure compliance with regulatory requirements, and safeguard sensitive processes and products.

Overall, measuring humidity in high-temperature processes allows for better process control, improved product quality, equipment protection, energy efficiency, and environmental compliance. It enables operators to make informed decisions and adjustments to ensure optimal performance and desired outcomes in challenging, high-temperature environments.

Absolute Humidity Analogue Sensor HT350

High temperature absolute humidity analogue sensor using latest heat pipe technology, suitable for process temperatures as high as 350°C (662°F).
Measuring of absolute humidity as well as the process temperature.
The humidity sensor works on the dew point & heat pipe principle, based on a stable thermal system.
The robust sensor tip is completely sealed and allows to be used in polluted environment applications. Therefore, easy cleaning is possible, if necessary.
Two versions, with active and passive cooling respectively are available.
Passive cooling is recommended to be selected for applications with polluted environments.


  • Absolute humidity measuring
  • Temperature measuring
  • Direct placement in process room
  • Sealed metal measuring tip
  • Contamination resistant
  • Maintenance-free
  • Easy mounting

Technical Data

Humidity measuring range 0 … 100 Vol% @ t > 100 °C
Humidity accuracy at 20Vol%: ± 3,5%
 at 90Vol%: ± 1,5%
Response time (t90)
          with increase of 20 … 100Vol%: <10s
          with decrease of 100 … 20Vol%:  <60s Stabilization
          after switching approx. 10min
Temperature measuring range 0 … 350 °C
Temperature accuracy 0,5 ° ± 0,75 %  of range
Operating temperature Probe          0 … 350 °C
Electronics   5 … 60 °C
            Moisture 4 … 20 mA, Load < 600Ω
0 … 10V optional,  Load >600Ω
short circuit protected
          Temperature 0-10V …Load > 600Ω,
short circuit protected
RS 485  Interface
Power supply 12 VDC
Current consumption 8,5 A
Electrical connection terminal blocks
Probe dimensions
             Length                140 mm + 50 mm
             Diameter 26,9mm/3mm/4mm
Electronics Plastic Housing
Humidity Copper, Nickel
Temperature sensor V4A, 1.4301
Protection rating Probe IP67,   Electronics IP 65


Applications where a high temperature up to 350C humidity sensor is needed

A high-temperature humidity sensor capable of operating at up to 350°C can be useful in a variety of applications where monitoring and control of humidity is critical in extreme heat environments. Here are some examples:

Industrial ovens and kilns: In processes such as drying, baking, or curing, where high temperatures are involved, it is essential to monitor humidity levels to ensure the desired product quality and prevent defects.

Furnaces and boilers: High-temperature humidity sensors can be used to monitor the humidity levels in industrial furnaces and boilers to optimize combustion efficiency, reduce emissions, and prevent corrosion.

Automotive and aerospace: In engine testing and research, as well as aerospace applications, humidity sensors capable of withstanding high temperatures can provide valuable data for understanding the performance and behavior of engines and systems under extreme conditions.

Environmental chambers and testing: High-temperature humidity sensors are used in environmental chambers to simulate and test the effects of humidity and temperature on materials, electronics, and other components.

Petrochemical and refineries: In refineries and petrochemical plants, humidity sensors operating at high temperatures can be employed to monitor the moisture content in various processes, helping to ensure product quality, prevent corrosion, and maintain safe operating conditions.

Semiconductor manufacturing: In certain stages of semiconductor fabrication processes, high-temperature humidity sensors are required to monitor and control humidity levels, as excess moisture can adversely affect the performance and reliability of semiconductor devices.

Energy generation: Power plants, especially those utilizing steam or gas turbines, can benefit from high-temperature humidity sensors to monitor the moisture content in the air or combustion gases, enabling efficient operation and reducing the risk of equipment damage.

It's worth noting that the specific requirements of a high-temperature humidity sensor may vary depending on the application, such as the temperature range, accuracy, response time, and environmental conditions.

Additional Applications

  • Drying systems
  • Baking ovens
  • Ceramic dryers
  • Food industry
  • Animal feed production
  • Cement industry
  • Wood industry