Humidity

Our Hygrasgard® moisture sensors for indoor and outdoor use measure the relative humidity and the temperature of the ambient air. The sensor device calculates different values ​​from these measurements: relative moist [% R.H.], absolute moist [g/m³], mixing ratio [g/kg], dew point temperature [° C], enthalpy [kj/kg] and room temperature [° C]..

Guides and useful information about humidity
264 products
  • HYGRASGARD® DFF-U
    %RH

    HYGRASGARD® DFF-U

    1201-6131-0000-100

    $427.20

    incl. VAT $508.33

  • HYGRASGARD® RPFTF-20-Modbus
    °C %RH
    Modbus

    HYGRASGARD® RPFTF-20-Modbus

    1201-1276-1000-101

    $430.27

    incl. VAT $511.97

  • HYGRASGARD® DFTF-I
    °C %RH

    HYGRASGARD® DFTF-I

    1201-6132-1000-100

    $437.55

    incl. VAT $520.58

  • HYGRASGARD® DFTF-U
    °C %RH

    HYGRASGARD® DFTF-U

    1201-6131-1000-100

    $437.55

    incl. VAT $520.58

  • HYGRASGARD® AFTF-20-I Q LCD
    °C %RH

    HYGRASGARD® AFTF-20-I Q LCD

    2003-6122-2100-001

    $442.76

    incl. VAT $526.74

  • HYGRASGARD® AFTF-20-U Q LCD
    °C %RH

    HYGRASGARD® AFTF-20-U Q LCD

    2003-6122-1100-001

    $442.76

    incl. VAT $526.74

  • HYGRASGARD® KFTF-20-I Q LCD
    °C %RH

    HYGRASGARD® KFTF-20-I Q LCD

    2003-4172-2100-001

    $442.76

    incl. VAT $526.74

  • HYGRASGARD® KFTF-20-U Q LCD
    °C %RH

    HYGRASGARD® KFTF-20-U Q LCD

    2003-4172-1100-001

    $442.76

    incl. VAT $526.74

  • HYGRASGARD® AFF-25-I
    %RH

    HYGRASGARD® AFF-25-I

    1201-7132-0000-101

    $444.40

    incl. VAT $528.76

  • HYGRASGARD® AFF-25-U
    %RH

    HYGRASGARD® AFF-25-U

    1201-7131-0000-101

    $444.40

    incl. VAT $528.76

  • HYGRASGARD® AFTF-ECATP
    °C %RH

    HYGRASGARD® AFTF-ECATP

    2003-6261-9100-001

    $458.14

    incl. VAT $545.16

  • HYGRASGARD® AFTF-25-I
    °C %RH

    HYGRASGARD® AFTF-25-I

    1201-7132-1000-101

    $471.38

    incl. VAT $560.87

  • HYGRASGARD® AFTF-25-U
    °C %RH

    HYGRASGARD® AFTF-25-U

    1201-7131-1000-101

    $471.38

    incl. VAT $560.87

  • HYGRASGARD® RPFTF-Modbus-T3 LCD
    °C %RH
    Si Imp Modbus

    HYGRASGARD® RPFTF-Modbus-T3 LCD

    1201-6246-1400-000

    $475.47

    incl. VAT $565.72

  • HYGRASGARD® RPFTF-20-Modbus-T3
    °C %RH
    Si Imp Modbus

    HYGRASGARD® RPFTF-20-Modbus-T3

    1201-6246-1000-001

    $481.02

    incl. VAT $572.41

  • HYGRASGARD® KFTF-ECATP
    °C %RH

    HYGRASGARD® KFTF-ECATP

    2003-4221-9100-001

    $485.10

    incl. VAT $577.25

Humidity measure, monitor and control in building automation and industry

Author: T. Graf | Last update: 07.04.2026

Humidity is a key influencing factor in building automation, ventilation and air conditioning technology as well as in many industrial processes. It not only influences the indoor climate and energy efficiency, but also the service life of buildings, systems and materials.

Depending on the application, different solutions are used - from continuous moisture measurement to targeted monitoring of limit values or condensation.

In a nutshell

Humidity describes the water content of the air and is a decisive control variable in HVAC systems and building automation.

This enables precise recording and monitoring:

  • Demand-based control of ventilation and air conditioning
  • Protection against mold growth and moisture damage
  • Stable conditions for industrial processes
  • Improving comfort and air quality

Different types of device are used depending on the requirements:
Humidity sensors for continuous measurement, hygrostats for limit value monitoring and condensation monitors, dew point monitors, leakage sensors to protect against condensation or liquid leakage.

Contents

Applications in building automation and HVAC The most important solutions at a glance Measured variables around Humidity Dampening solutions at a glance - find suitable products

Why is Humidity a critical measured variable?

In practice Humidity is rarely isolated - it is always related to temperature, air movement and surfaces.

Typical effects:

  • Too high Humidity
    - Condensation on cold surfaces
    - Mold formation and microbial growth
    - Corrosion and material damage
  • Too low Humidity
    - Drying out of materials
    - Cracking (e.g. wood, plaster)
    - Impairment of comfort and health
  • Unstable moisture values
    - Inefficient control of HVAC systems
    - Unnecessary energy consumption
    - Fluctuating process conditions

Therefore Humidity in modern buildings a active control variable - not just a measured value.

Applications in building automation and HVAC

Comfort and indoor climate

  • Offices, hotels, residential buildings
  • Schools and public institutions

Technical installations

  • Ventilation and air conditioning systems
  • Cooling and heating systems

Special areas

  • Clean rooms and laboratories
  • Storage and production environments
  • Swimming pools and wet rooms

Building protection

  • Avoidance of condensation
  • Protecting the building envelope
  • Humidity monitoring in critical zones

The most important solutions at a glance

Different types of device are used depending on the objective. These each fulfill clearly defined tasks.

Humidity sensors - Continuous measurement

Humidity sensors record the relative humidity as a continuous measured value and provide analog or digital output signals.

Typical areas of application:

  • Control of ventilation systems
  • Room climate monitoring
  • Integration in BMS/DDC systems

To the category: Humidity sensors

Hygrostate - Simple limit value control

Hygrostats work as switching devices. They react to defined humidity thresholds and switch fans or dehumidifiers, for example.

Typical areas of application:

  • Simple control loops without BMS
  • Retrofitting in existing buildings
  • Cost-efficient solutions

To the category: Hygrostate

Condensation and dew point monitors, leakage sensors - Protection from water

Condensation monitors detect when Humidity condenses on surfaces or is about to do so.

Typical areas of application:

  • Chilled ceilings and cooling surfaces
  • Ventilation ducts
  • Prevention of moisture damage

To the category: Condensation monitors, dew point monitors, leakage sensors

Measured variables around Humidity

Various parameters are used in practice:

  • Relative humidity (% RH) → most important variable in HVAC
  • Absolute humidity (g/m³) → for physical considerations
  • Dew point (°C) → decisive for condensation/dew point
  • Mixing ratio (g/kg) → in ventilation technology

Many modern sensors calculate these values directly from temperature and humidity.

Selection: Which solution suits the application?

The right choice depends heavily on the task at hand:

  • Continuous control required
    → Humidity sensor (e.g. 0-10 V, 4-20 mA or Modbus)
  • Simple on/off control is sufficient
    → Hygrostat
  • Condensation protection required
    → Condensation monitor or dew point monitor
  • Building automation available
    → Preferably sensors with standard signal or bus communication

The decisive factor is always: What should be regulated or protected - and how exactly?

Integration in building automation and systems

Today, humidity measurement is an integral part of modern building management systems.

Typical integrations:

  • DDC controller in HVAC systems
  • BMS systems (BACnet, Modbus)
  • Energy management systems
  • Smart building applications

The combination of humidity and temperature values enables significantly more efficient control strategies than individual variables.

Dampening solutions at a glance - find suitable products

Different product categories are available depending on the application and system requirements:

Select the right solution for your application and system architecture

We also manufacture individually

Do you have special requirements? As a manufacturer with our own production facilities in Germany, we are also able to produce products outside of the standard range at any time.

 Contact us

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