• Hand-Held Humidity and Temperature Meter

Hand-Held Humidity and Temperature Meter

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The Vaisala HUMICAP HM70 portable humidity and temperature indicator is designed for demanding on-site humidity measurements.

The Vaisala HUMICAP Handheld Humidity and Temperature Meter HM70 is designed for demanding humidity measurements in spot-checking applications. It is also ideal for field checking and calibration of Vaisala's fixed humidity instruments.


  • Multilingual user interface
  • Shows measurement trends graphically
  • Multiprobe operation; dew point and CO2 probes can also be connected
  • Displays various humidity parameters including dew point, ppm, water vapor pressure, saturation water vapor pressure, wet bulb temperature, absolute humidity, mixing ratio and enthalpy
  • 2 Data can be logged, and transferred to a PC via MI70 Link software
  • Displays various humidity parameters
  • Sensor preheat and chemical purge options for demanding conditions
  • 6-point traceable calibration (certificate included)

Vaisala HUMICAP Technology 

The HM70 incorporates the latest generation of the Vaisala HUMICAP Sensor. It is reliable and has better than ever long-term stability. Additionally, it has a sensor that copes well with chemical interference and provides accuracy that lasts in demanding conditions.

Chemical Purge

The chemical purge option maintains measurement accuracy in environments with high concentrations of chemicals. The sensor preheat option reduces measurement delays as it keeps the sensor dry when the probe is inserted into hot and humid processes.

Three Probes to Choose From

The HMP75 is a general purpose probe whereas the HMP76 is a long, stainless steel probe especially suitable for spotchecking in ducts. The HMP77 is a small probe at the end of a 5-meter cable. The probe is ideal for di‚cult-to-reach areas and for on-site calibration of Vaisala's process transmitters. In addition, the HM70 supports the use of Vaisala's dew point, carbon dioxide and moisture in oil probes, allowing measurements in several multiparameter applications.

MI70 Link

The optional MI70 Link Windows software and the USB connection cable form a practical tool for transferring logged data and real time measurement data from the HM70 to a PC.

Relative Humidity

Measurement range0 ... 100 %RH
Accuracy including non-linearity, hysteresis and repeatability. Defined as ±2 standard deviation limits:
At +15 ... +25 °C (+59 ... +77 °F)±1 %RH (0 ... 90 %RH) ±1.7 %RH (90 ... 100 %RH)
At -20 ... +40 °C (-4 ... +104 °F) ±(1.0 + 0.008 x reading) %RH
At -40 ... +180 °C (-40 ... +356 °F)  At -40 ... +180 °C (-40 ... +356 °F) 
Factory calibration uncertainty (+20 °C / +68 °F) ±0.6 %RH (0 ... 40 %RH)
±1.0 %RH (40 ... 97 %RH)
Response time (90%) at +20 °C (+68 °F) in still air:
HMP75 (with standard plastic grid) 17 s
HMP76 (with standard sintered bronze filter) 60 s
HMP77 (with standard plastic grid and stainless steel netting) 50 s
Typical long-term stability  better than 1 %RH / year


HMP75 measurement range -20 ... +60 °C (-4 ... +140 °F)
HMP76 measurement range -50 ... +120 °C (-58 ... +248 °F)
HMP76 short time measurement range -50 ... +180 °C (-58 ... +356 °F)
HMP77 measurement range -70 ... +180 °C (-94 ... +356 °F)
Accuracy at +20 °C (+68 °F) ±0.2 °C (±0.36 °F)
Accuracy over temperature range: 
 Other Variables Availabledew point, frost point, absolute humidity, mixing ratio, wet bulb temperature,water content, vapor pressure, saturation vapor pressure, enthalpy, water activity
Humidity sensorHUMICAP 180R
HUMICAP 180RC (chemical purge,sensor preheat)
Temperature sensorPt100 RTD Class F0.1 IEC 60751
Operating temperature range for electronics -40 ... +60 °C ( -40 ... +140 °F)

Standard Sensor Protection

HMP75plastic grid
HMP76sintered bronze filter
HMP77grid with SS netting
Housing classificationIP65 (NEMA 4)
Housing materialABS/PC blend
Probe materialStainless steel (AIS316L)
Probe cable length (between indicator and the probe handle)1.9 m
Probe cable length of HMP77 (from handle to the root of probe)5.0 m 
Probe diameter 12 mm (0.47 inch) 


HMP75250 g
HMP76 350 g
HMP77500 g

Operating Environment

Operating temperature-10 ... +40 °C (+14 … +104 °F)
Operating humidity0 ... 100 % RH, non-condensing
Storage temperature -40 ... +70 °C (-40 ... +158 °F)

Inputs and Outputs

Max. no of probes 2
Power supplyRechargeable NiMH battery pack with
AC adapter or 4xAA size alkalines,
type IEC LR6
PC interface MI70 Link software with USB or serial port cable

Analog Output

Scale0...1 VDC
Output resolution0.6 mV
Accuracy0.2 % full scale
Temperature dependence0.002 %/˚C full scale
Minimum load resistor10 kΩ to ground

Mechanical Specifications

Housing classificationIP54
Housing materialsABS/PC blend
Weight400 g


EMC complianceEN61326-1, Portable Equipment


Menu languagesEnglish, Chinese, Spanish, Russian, French, Japanese, German, Swedish, Finnish
Display• LCD with backlight
• Graphic trend display of anyparameter
• Character height up to 16 mm
AlarmAudible alarm function
Data logging capacity2700 real time data points
Logging interval1 s to 12 h
Logging duration1 min ... memory full
Resolution0.01 %RH, 0.01 °C/°F, 0.01 hPa,
0.01 aw, 10 ppm / 0.01% CO2
Typical charging time4 hours

Operation Times

Continuous use48 h typical at +20 ˚C (68 °F)
Data logging use up to a month