testo 635-1 - Humidity measuring instrument

Order-Nr.  0560 6351

  • Measures air humidity, temperature, absolute pressure and dew point in compressed air

  • Optional attachable probes

  • Display of min., max. and mean values

  • Cyclical printing of readings at freely adjustable intervals

The testo 635-1 for temperature and humidity measurement with its State-of-the-art technology and large selection of probes allows you to measure temperature, air humidity and dew point – in compressed air as well.

This meter uses a sensor to start up.

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Rs  37,880.00
GST and accessories extra

Product Description

The testo 635-1 for temperature and humidity measurement is ideally equipped for checking the air humidity, temperature and dew point in living areas, in production, storage and server areas and in museums and cold stores. It also aids the measurements of the ambient absolute pressure and dew point in compressed air can be quickly and efficiently.

Attachable optional probes are available for recording the following values:
• Air humidity
• Material moisture
• Pressure dew point in compressed air
• Air temperature
• Surface temperature
• Core temperature
• U-value
• Absolute pressure

The testo 635-1 for temperature and humidity measurement has two probe inputs for plug-in probes with cables. In addition, upto three further temperature or humidity probes can be displayed with the testo 635-1 via radio-controlled data transmission i.e. wireless.

Robust, practical and easy to handle
In addition to readings, the testo 635-1 temperature and humidity measurement instrument also displays min., max. and mean values.
While the pressure dew point probe measures the pressure dew point in compressed air, the humidity probe helps in measuring the dew point and water content of indoor air along with the psychrometric temperature, in addition to air humidity and air temperature.
The measuring instrument also calculates the dew point distance between indoor air and wall surface. The “Applications” tab in testo 635-1, indicates whether a mould in the home has been caused by incorrect use of ventilation or by moisture ingress.
The user-friendly menu guidance, illumination function for reading legibility even in poor visibility and impact resistance due to its solid housing makes testo 635-1 very reliable and easy to use.

Documentation of measurement data with testo 635-1 temperature and humidity measuring instrument
The optional testo fast printer enables you to print out measurement data such as air humidity or temperature easily at any time.
The practical cyclical printing function on the testo 635-1 not only enables the printout of individual readings, but also of whole series of measurements on the testo fast printer at freely adjustable intervals (for example once a minute).


Delivery Scope

testo 635-1 temperature and humidity measuring instrument, including calibration protocol and batteries.

CAUTION: The instrument can only be commissioned with a probe. These are available separately.

Temperature - NTC

Measuring range

-40 to +150 °C


±0.2 °C (-25 to +74.9 °C)

±0.4 °C (-40 to -25.1 °C)

±0.4 °C (+75 to +99.9 °C)

±0.5 % of mv (Remaining Range)


0.1 °C

Temperature - TC Type K (NiCr-Ni)

Measuring range

-200 to +1370 °C


±0.3 °C (-60 to +60 °C)

±(0.2 °C + 0.5 % of mv) (Remaining Range)


0.1 °C

Humidity - Capacitive

Measuring range

0 to +100 %RH


See probe data


0.1 %RH

Absolute Pressure

Measuring range

0 to 2000 hPa


See probe data


0.1 hPa

General technical data


428 g


220 x 74 x 46 mm

Operating temperature

-20 to +50 °C

Product-/housing material

ABS / TPE / Metal

Battery type

Alkali manganese, mignon, type AA

Battery life

200 h

Storage temperature

-30 to +70 °C

Air probes

Rs  7,480.00
GST and accessories extra

Pressure dewpoint probes

Rs  88,040.00
GST and accessories extra

Surface probes

Rs  6,240.00
GST and accessories extra
Rs  15,940.00
GST and accessories extra
Rs  40,590.00
GST and accessories extra
Rs  5,420.00
GST and accessories extra


Rs  3,470.00
GST and accessories extra
Rs  3,610.00
GST and accessories extra

Printer and accessories

testo fast printer IRDA

Order Number: 0554 0549

Rs  27,710.00
GST and accessories extra
Rs  3,060.00
GST and accessories extra

Localising mould

Damp ceilings and walls may be a result of structural damage. In most cases, however, it is a sign of improper ventilation. Once the mould appears inside a house, the tenant assumes that moisture has come in from outside. Numerous disputes have erupted because of the issue of who is liable for the mould damage. However, it is difficult to find out who or what has caused the mould: the tenant or faulty structural design?

Testo 635-1 is ideal for measuring moisture in ceilings and walls. Using the optional attachment temperature/moisture probe and optional surface temperature probe, the testo 635 automatically calculates the dew point distance. It provides initial information about whether mould is being caused by condensation, or from moisture ingress due to structural damage or faulty insulation.

Monitoring production and storage conditions

Our temperature/humidity measuring instruments are used around the world in production, storage and server rooms, museums, archives, cold storage warehouses, containers and sales counters.

Manufacturers, carriers, or dealers of sensitive products must ensure that specified temperature or humidity values are observed during production and storage. The testo 635 offers the option of performing spot measurements in relevant places.

The temperature/humidity measuring instrument testo 635-2 offers the user a wide range of humidity/moisture probes. It provides the option of measuring humidity, material moisture and U-value (for the thermal assessment of structural components). In addition to the standard probes, up to three radio probes can be connected to the device in parallel. Measurement results can be analysed, stored and documented using the supplied PC software.

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