Testo 635 Thermo Hygrometer
Starting at $445.00
Starting at $400.50

Not in stock. Usually ships in 3-5 business days [?]

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This meter requires probes which must be purchased separately. See the accessories tab.


  • Range and Accuracy is probe dependant
  • Compatible with optional wireless probes
  • 5 probe inputs
  • Characteristic curves allows material moisture calculation
  • Large, backlit display
  • Optional 10,000 reading memory (model 635-2)
  • Protection against dirt and impact (IP 54)

The Testo 635 thermo hygrometer offers quick and easy humidity, equilibrium moisture, and pressure dew point measurements. Compatible with wireless probes, the Testo 635 thermo hygrometer combines advanced features with proven reliability to deliver measuring confidence in the most demanding applications.

Wireless probes offer many advantages over traditional cable or integrated probes. There is no risk of damaging or tangling wires or cables and measurements up to 65 ft. are possible. With the Testo 635 thermo hygrometer, up to three wireless probes can be read and displayed at once for temperature and humidity measurements. The optional, easily installed wireless module can be retrofitted at any time in either Testo 635 thermo hygrometer model. For wireless use, a wireless module, wireless handle, and wireless probe is required. These are available as accessories.

Whether using wireless or standard probes, the Testo 635 thermo hygrometer uses humidity and temperature readings to determine a wide range of air moisture measurements. All are displayed on the large, backlit display for easy viewing including differential and mean values. Three function buttons provide access to advanced instrument features. Ten material characteristics curves are programmed into the Testo 635 thermo hygrometer to help determine equilibrium moisture.

The Testo 635 thermo hygrometer offers several options for viewing, managing, printing and analyzing data. The Testo 635-2 thermo hygrometer includes memory for up to 10,000 readings and ComSoft3 Compact Software for analyzing data in graphics and tables. The optional Testo printer provides wireless infrared printing of all channels for fast and convenient on-site documentation.

The Testo 635 thermo hygrometer is rugged by design and able to stand up to daily measuring tasks. The rubberized housing, offers protection against dirt and impact, and will help protect your instrument. The Testo 635 thermo hygrometer is also equipped with a convenient carrying strap plus two powerful magnets in back that allow secure hands free operation.

Required Components

These additional components are required for the operation of your product. We strongly advise you to purchase these components unless you already own them or own a suitable alternative.

Testo Standard Probes
Wide range of probes for use with the Testo 635 thermo-hygrometer
Testo Wireless Probes
Wireless probes for use with Testo meters


Please consider these optional accessories.

Testo Wireless Module
Wireless module for upgrading Testo meters to a wireless option
Testo Wireless Handle
Wireless handle for plug-in probe heads
Testo Infrared Printer
Testo printer with wireless IRDA and infrared interface
Testo Thermal Printer Paper
Thermal paper for Testo Infrared printer
In Stock
Testo Plug-In Power Supply
Plug-in mains adapter, 5 VDC 500 mA with European adapter, 100-250 VAC, 50-60 Hz
Testo 0516 1435 Case
Deluxe service case for Compact Pro (435 & 635)


This product can be used in the following applications: