Buy Rotronic HF Transmitters here

Humidity and temperature are not just comfort parameters. In HVAC systems, clean rooms, pharmaceutical production, food processing, storage rooms, greenhouses, museums, paper industries and industrial ducts, poor humidity control can affect product quality, process stability, energy efficiency and equipment life.

That is why choosing the correct humidity and temperature transmitter matters.

Rotronic HF transmitters are used for reliable measurement of relative humidity, temperature and, in selected models, calculated parameters such as dew point. Depending on the model, they can be used in simple HVAC rooms, duct installations, BMS systems, industrial process areas, hazardous zones and harsh outdoor environments.

At Radical TechMart, we supply multiple Rotronic HF transmitter models so buyers can select the right transmitter according to application, mounting, output, housing, communication requirement and installation environment.

This guide will help you compare the available Rotronic HF transmitters and choose the right model for your requirement.

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Why Rotronic HF Transmitters Are Used in Industrial and HVAC Applications

Rotronic HF transmitters are preferred where humidity and temperature values need to be sent to a controller, PLC, BMS, SCADA, data logger or monitoring system.

They are commonly selected because they offer:

• Relative humidity and temperature measurement
• Analog output options for control systems
• Wall and duct mounting options
• Models for HVAC, BMS and industrial applications
• Dew point calculation in selected models
• Probe flexibility in higher-end models
• Versions suitable for harsh and hazardous environments
• Reliable use in pharma, food, printing, paper and climate monitoring applications

The main selection point is not only accuracy. The right model depends on where it will be installed, what output your system needs, whether the area is normal or hazardous, and whether you need basic monitoring or advanced process control.

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Quick Selection Guide for Rotronic HF Transmitters

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Product-Wise Selection Guide

1. Rotronic HygroFlex1 Humidity & Temperature Transmitter without Display

The Rotronic HygroFlex1 is suitable when the application needs a simple, cost-effective humidity and temperature transmitter for HVAC use. It is designed for basic building ventilation, air conditioning and climate monitoring applications where a reliable analog signal is required.

This model makes sense when the buyer wants Rotronic measurement quality but does not need an advanced display, complex communication protocol or heavy industrial housing.

Technical points to note:

• Measures relative humidity and temperature
• Uses Rotronic Hygromer IN-1 humidity sensor
• Accuracy for wall and duct version: less than ±2 %RH from 10 to 90 %RH
• Adjustable at 35 %RH and 80 %RH
• Wall, space mount and duct versions available
• Duct probe versions include 100 mm and 300 mm probe length options
• ABS housing
• IP65 for wall/duct versions; space mount version has lower protection

Where it is commonly used:

• HVAC systems
• Building ventilation
• Air conditioning control
• BMS humidity monitoring
• Room climate monitoring
• Duct humidity measurement

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2. Rotronic HF1 Basic Humidity and Temperature Transmitter

The Rotronic HF1 Basic Humidity and Temperature Transmitter is ideal for buyers who need an economical transmitter for simple humidity and temperature measurement. It fits well in HVAC projects where the transmitter is used as a field device connected to a controller or BMS.

This product is mainly for users who want dependable measurement without paying for advanced industrial features they may not use.

Technical points to note:

• Basic humidity and temperature transmitter
• Suitable for HVAC use
• Wall, space and duct mounting options depending on variant
• Analog output for humidity and/or temperature
• HygroSoft software support for scaling, calibration and adjustment
• Uses Rotronic Hygromer sensor technology
• Suitable for standard building environments

Where it is commonly used:

• HVAC control panels
• Ventilation systems
• Air handling units
• Building management systems
• Office and commercial buildings
• General indoor climate monitoring

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3. HF3 Humidity and Temperature Transmitter

The Rotronic HF3 is suitable for HVAC and indoor climate control applications where appearance, room installation and reliable measurement are important. It is used in locations such as offices, museums, warehouses and libraries where humidity and temperature stability can affect comfort, stored materials or environmental control.

Choose HF3 when the installation is not extremely industrial but still needs dependable humidity and temperature monitoring.

Technical points to note:

• Measures relative humidity and temperature
• Can calculate dew point
• Freely programmable and scalable analog outputs
• Models with display are available
• Suitable for room, wall and duct-style installations depending on variant
• Used for HVAC and climate control
• Improved accuracy options mentioned in the HF3/HF4 catalogue

Where it is commonly used:

• Office buildings
• Museums
• Warehouses
• Libraries
• HVAC rooms
• Indoor climate monitoring systems

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4. Rotronic HF4 Series Humidity and Temperature Transmitter

The Rotronic HF4 Series is suitable when the application needs more flexibility than a basic room transmitter. It is commonly used in HVAC and climate control systems where wall or duct measurement, analog outputs and optional communication features are required.

HF4 is a better option when the buyer needs a more configurable transmitter than HF1 or HF3 but does not necessarily require the full industrial flexibility of HF5.

Technical points to note:

• Measures relative humidity and temperature
• Can calculate dew point
• Freely programmable and scalable analog outputs
• Wall and duct versions available
• Display options available
• Models with Ethernet/LAN and RS-485 mentioned
• Humidity and temperature adjustment options available

Where it is commonly used:

• HVAC duct systems
• BMS-connected climate monitoring
• Office buildings
• Storage rooms
• Museums and libraries
• Commercial ventilation systems

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5. Rotronic HF5 Series

The Rotronic HF5 Series is suitable for buyers who need an industrial-grade humidity and temperature transmitter for more demanding applications. It is used in HVAC, food industry, pharmaceutical industry, printing and paper industries.

Choose HF5 when the application needs stronger configuration flexibility, probe compatibility, analog output scaling and possible digital networking options.

Technical points to note:

• Measures relative humidity, temperature and dew point
• Wall and duct mounting possible
• Robust industrial-quality housing
• Freely programmable and scalable analog outputs
• Two analog outputs
• HF52, HF53, HF54 and HF56 versions mentioned
• Optional digital outputs: RS-485, Ethernet and wireless
• Compatible with a wide range of HygroClip2 probes
• Power supply options include low-voltage and mains-voltage variants depending on model
• ABS / Aluminum housing option mentioned for HF5xxS

Where it is commonly used:

• HVAC technical rooms
• Ventilation shafts
• Pharmaceutical manufacturing
• Food industry
• Printing and paper industries
• Industrial humidity monitoring systems

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6. HygroFlex HF5 Advanced Humidity and Temperature Transmitter

The HygroFlex HF5 Advanced, also represented by the HF5A transmitter catalogue, is suitable for users who need a more modern HF transmitter with NFC configuration, interchangeable probes and flexible output options.

This model is useful when the buyer needs advanced setup flexibility, easy scaling and compatibility with standard, industrial or RMS probes.

Technical points to note:

• Measures relative humidity, temperature and dew point
• Interchangeable probes
• Compatible with standard, industrial and RMS probes
• Freely programmable outputs via NFC interface
• Supports NFC powerless configuration
• Wall mount version available
• Duct kit version available using extension cable and mounting gland
• HF5A-2, HF5A-3 and HF5A-D versions mentioned
• RS485 signal available on screw terminal for HF5A-D
• Power supply: 18 to 36 VDC
• Industrial-quality IP65 housing

Where it is commonly used:

• Pharma humidity monitoring
• Food processing areas
• HVAC and BMS systems
• Printing and paper industries
• Industrial process monitoring
• Applications requiring probe extension or flexible mounting

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7. Rotronic HF5 Main Voltage Humidity and Temperature Transmitter

The Rotronic HF5 Main Voltage version is suitable when the site has mains power available and the transmitter needs to be powered directly from a higher-voltage supply instead of only low-voltage DC or AC instrumentation power.

This is useful in installations where 24 VDC supply is not conveniently available near the transmitter point, or where the control panel design uses mains-powered field instrumentation.

Technical points to note:

• Based on Rotronic HF5 Series catalogue
• Measures relative humidity, temperature and dew point
• Two freely selectable and scalable analog outputs
• Wall or duct mounting possible depending on version
• Optional digital outputs mentioned for HF5 series
• Mains power option: 100 to 240 VAC with galvanic isolation
• Suitable for applications needing stronger installation flexibility
• Probe options available depending on selected HF5 configuration

Where it is commonly used:

• Industrial HVAC systems
• Control rooms
• Technical rooms
• Process monitoring panels
• Pharma and food plants
• Building automation systems

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8. Rotronic HF5 Aluminum Humidity and Temperature Transmitter

The Rotronic HF5 Aluminum version is useful when the buyer needs an HF5 transmitter with a more robust housing option compared with standard plastic housing. Aluminum housing is preferred in tougher industrial areas where mechanical strength and long-term durability are important.

This model should be considered when the installation environment is more demanding than a normal HVAC room but does not necessarily require an explosion-proof transmitter.

Technical points to note:

• Based on Rotronic HF5 Series catalogue
• Measures relative humidity, temperature and dew point
• Freely programmable and scalable analog outputs
• Wall or duct installation depending on version
• Optional digital outputs such as RS-485, Ethernet and wireless mentioned
• Compatible with different probe types depending on configuration
• Aluminum housing option mentioned for HF5xxS
• Suitable for industrial-quality installation requirements

Where it is commonly used:

• Industrial HVAC areas
• Technical rooms
• Manufacturing plants
• Pharma and food facilities
• Printing and paper industries
• Plant monitoring systems

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9. Rotronic HF5-EX Series Humidity & Temperature Transmitter

The Rotronic HF5-EX Series is designed for humidity and temperature measurement in explosive or hazardous environments. This is not a general HVAC transmitter. It should be selected when the installation area requires certified equipment for gas or dust explosion protection.

This model is suitable for industries where humidity and temperature monitoring is needed inside or near hazardous zones.

Technical points to note:

• Intrinsically safe humidity and temperature transmitter
• Measures relative humidity and temperature
• Calculates psychrometric parameters
• HF520-EX-W wall version available
• HF520-EX-D duct version available
• Robust aluminum housing
• IP66 protection class
• 10 to 28 VDC power supply
• Two analog outputs, freely selectable and scalable
• 2-wire, 2 x 4 to 20 mA output
• Interchangeable probes
• Suitable for explosive gas and dust environments depending on certification

Where it is commonly used:

• Hazardous process areas
• Pharmaceutical industry
• Food industry
• Printing and paper industries
• Chemical-related environments
• HVAC in explosive zones

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10. Rotronic HygroFlex HF73A Heavy Duty Humidity & Temperature Transmitter

The Rotronic HygroFlex HF73A is suitable for harsh industrial and outdoor duct environments where normal transmitters may not be strong enough. It is designed for humidity, temperature and dew point measurement in demanding conditions.

Choose HF73A when the installation involves industrial ducts, drying processes, outdoor exposure or harsh plant conditions.

Technical points to note:

• Measures relative humidity, temperature and dew point
• Robust industrial housing for harsh conditions
• Industrial aluminum housing
• Duct mounting
• Fixed PPS probe for duct mounts
• Three probe lengths available
• Two freely selectable and scalable analog outputs
• 3-wire version with dew point / frost point calculation
• Power supply: 15 to 40 VDC / 12 to 28 VAC
• Probe application range mentioned up to -100 to 200 °C depending on probe context
• Humidity sensor: HYGROMER HT-1
• Accuracy: ±1.0 %RH / 0.2 K at 23 °C for fixed probe data
• IP65 protection mentioned

Where it is commonly used:

• Harsh industrial environments
• Outdoor duct installations
• Drying processes
• Food production
• Pharmaceutical production
• Industrial ventilation ducts

Rotronic HygroFlex HF73A Heavy Duty Humidity & Temperature Transmitter

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How to Choose the Right Rotronic HF Transmitter

1. First confirm the installation location

The first selection point is where the transmitter will be installed.

• Room installation: HF1, HF3
• Wall installation: HF1, HF3, HF4, HF5, HF5A, HF5-EX
• Duct installation: HF1, HF4, HF5, HF5A duct kit, HF5-EX, HF73A
• Harsh duct / outdoor installation: HF73A
• Hazardous area installation: HF5-EX

Do not select only based on price. A low-cost room transmitter may not survive or perform properly in a harsh duct or process environment.

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2. Confirm output requirement

Most industrial and HVAC systems need signals that can connect to:

• PLC
• SCADA
• BMS
• Controller
• Indicator
• Data logger
• Monitoring system

For simple applications, analog output may be enough. For advanced systems, RS485, Ethernet or network capability may be required.

HF5 and HF5A are better suited when communication and configuration flexibility are important.

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3. Confirm whether dew point is required

Some applications need only relative humidity and temperature. Others also need dew point for condensation control, drying process monitoring or moisture analysis.

Models such as HF3, HF4, HF5, HF5A and HF73A mention dew point calculation capability.

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4. Confirm the environment

For normal HVAC applications, HF1 or HF3 may be enough. For industrial environments, HF5 or HF5A may be more suitable. For hazardous environments, HF5-EX should be considered. For harsh duct and outdoor conditions, HF73A is a stronger choice.

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5. Confirm probe requirement

Probe selection matters in humidity measurement. Buyers should confirm:

• Fixed or interchangeable probe
• Probe length
• Duct insertion depth
• Temperature range
• Stainless steel or plastic probe requirement
• Filter requirement
• Cable extension requirement
• Calibration and maintenance access

HF5, HF5A and HF5-EX are stronger choices when probe flexibility is important.

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Why Buy Rotronic HF Transmitters from Radical TechMart?

Choosing the right humidity and temperature transmitter is not only about selecting a model number. The buyer must confirm mounting, output, power supply, probe type, environment, communication and control system compatibility.

Radical TechMart helps buyers select the correct Rotronic HF transmitter based on actual site requirements.

You can contact us for:

• Rotronic HF transmitter model selection
• Price and availability
• Datasheet-based technical confirmation
• Suitable model for HVAC, pharma, BMS and industrial use
• Wall or duct mounting selection
• Analog / RS485 / Ethernet output guidance
• Hazardous area and heavy-duty application support

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FAQs About Rotronic HF Transmitters

1. Which Rotronic HF transmitter is best for basic HVAC applications?

For basic HVAC humidity and temperature monitoring, Rotronic HF1 / HygroFlex1 is a suitable choice. It is cost-effective and designed for standard HVAC applications.

2. Which Rotronic transmitter should I choose for office rooms, museums and libraries?

For indoor climate control in offices, museums, warehouses and libraries, Rotronic HF3 is a practical option because it is suited for room and climate monitoring applications where appearance and stable measurement matter.

3. What is the difference between HF3 and HF4?

HF3 is more suitable for room and basic HVAC climate monitoring, while HF4 provides more flexibility for wall and duct applications and may include communication options such as Ethernet/LAN and RS-485 depending on model.

4. Which Rotronic HF transmitter is suitable for industrial applications?

For industrial HVAC, pharma, food, printing and paper applications, Rotronic HF5 Series or HF5A Advanced are better choices because they offer stronger output flexibility, probe options and configuration capability.

5. Which Rotronic transmitter should I use for hazardous areas?

For hazardous or explosive environments, choose the Rotronic HF5-EX Series. Before selection, confirm zone classification, gas/dust requirement, probe type and certification suitability.

6. Which model is suitable for harsh duct or outdoor environments?

For harsh industrial duct and outdoor environments, Rotronic HygroFlex HF73A Heavy Duty is a suitable choice because it has a robust industrial aluminum housing and duct-mounted probe design.

7. Can Rotronic HF transmitters connect to PLC, SCADA or BMS systems?

Yes, depending on the selected model and output configuration. Many HF transmitters provide analog outputs, while selected models such as HF5 and HF5A offer digital or communication options depending on variant.

8. Do I need a display in a humidity transmitter?

A display is useful when operators need local reading at the installation point. If the signal is only used by a PLC, controller or BMS, a non-display version may be enough.

9. Is HF5 suitable for mains voltage applications?

Yes, the HF5 catalogue mentions a 100 to 240 VAC galvanically isolated power supply option. Before ordering, confirm that the exact selected HF5 model is the mains-voltage version.

10. How do I choose the right Rotronic HF transmitter?

Confirm the application, mounting type, output signal, power supply, probe type, environment, communication requirement and whether the area is normal, harsh or hazardous.

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Rotronic HF transmitters are available in different versions for basic HVAC rooms, ducts, BMS systems, industrial plants, hazardous zones and harsh outdoor applications.

Choosing the wrong model can lead to installation issues, signal mismatch, poor environmental suitability or unnecessary cost.