Extech RH25 Heat Index Psychrometer

  • Heat index sensor prevents heat stress risk
  • Pocket pen design fits any field kit easily
  • Measures RH from zero to 99.9 percent range
  • Heat index up to four hundred one Fahrenheit
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£62.78 (ex VAT)

£75.34 (inc VAT)

Earn 62 points

Usually ships In 1 to 2 weeks
  • Heat index sensor prevents heat stress risk
  • Pocket pen design fits any field kit easily
  • Measures RH from zero to 99.9 percent range
  • Heat index up to four hundred one Fahrenheit
Free Shipping

Spend over £100 on any new goods order and receive automatic free shipping

Rewards

Points make purchases! For every £1 spent, earn back 1p that can be spent on any future new goods purchase

Our Price Promise

We offer a Price Match Promise! Find an equivalent tester for a cheaper price on a competitor site, and we’ll do our best to match it

Express Delivery & Calibration

Express Delivery is currently unavailable for customers wishing to add calibration to their New Goods order. For more information, visit our Delivery Information page. 

£62.78 (ex VAT)

£75.34 (inc VAT)

Earn 62 points

Usually ships In 1 to 2 weeks
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Stay safe when heat soars. This slim sensor pen checks air temperature, humidity, and heat index in real time. Two clear lines on its display show data at a glance. Therefore you can act fast and dodge heat fatigue with the Extech RH25.

Precise Climate Insight

Moreover the Extech RH25 tracks wet bulb and dew point so you see the full climate story. It senses heat index up to 205 °C yet also reads icy zones down to −46 °C. In the same moment it keeps relative humidity accuracy within three percent. Thus it matches lab grade tools in a shirt pocket.

Built for the Field

For outdoor sport, site work, or patrol the Extech RH25 takes rough use. Its moulded shell shrugs off dirt while the recessed sensor cap guards the probe. Meanwhile the CR2032 cell powers many sessions. When power runs low the simple design lets you swap batteries in seconds.
Finally sliding the Extech RH25 into any pocket is easy thanks to its 140 mm length and 50 g weight. Even with gloves you can press one button and change from °C to °F fast. Hence every team member reads the same figures and acts with confidence. Choose this pen and move with heat-smart control.

Key Features
  • Extech RH25 displays live heat index readings
  • Calculates wet bulb temperature in one step
  • Shows WBGT to guide safe outdoor training
  • Reads dew point for precise storage control
  • Measures air temperature from minus four to 122 Fahrenheit
  • Captures humidity across the full zero to ninety nine point nine range
  • Accuracy within three percent RH supports quality checks
  • Compact 140 millimetre pen weighs only fifty grams
  • Single CR2032 cell powers the sensor without cables
  • CE certified build passes strict European standards
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Extech RH25 Heat Index Psychrometer

Stay safe when heat soars. This slim sensor pen checks air temperature, humidity, and heat index in real time. Two clear lines on its display show data at a glance. Therefore you can act fast and dodge heat fatigue with the Extech RH25.

Precise Climate Insight

Moreover the Extech RH25 tracks wet bulb and dew point so you see the full climate story. It senses heat index up to 205 °C yet also reads icy zones down to −46 °C. In the same moment it keeps relative humidity accuracy within three percent. Thus it matches lab grade tools in a shirt pocket.

Built for the Field

For outdoor sport, site work, or patrol the Extech RH25 takes rough use. Its moulded shell shrugs off dirt while the recessed sensor cap guards the probe. Meanwhile the CR2032 cell powers many sessions. When power runs low the simple design lets you swap batteries in seconds.

Finally sliding the Extech RH25 into any pocket is easy thanks to its 140 mm length and 50 g weight. Even with gloves you can press one button and change from °C to °F fast. Hence every team member reads the same figures and acts with confidence. Choose this pen and move with heat-smart control.

Key Features
  • Extech RH25 displays live heat index readings
  • Calculates wet bulb temperature in one step
  • Shows WBGT to guide safe outdoor training
  • Reads dew point for precise storage control
  • Measures air temperature from minus four to 122 Fahrenheit
  • Captures humidity across the full zero to ninety nine point nine range
  • Accuracy within three percent RH supports quality checks
  • Compact 140 millimetre pen weighs only fifty grams
  • Single CR2032 cell powers the sensor without cables
  • CE certified build passes strict European standards
Technical Specifications
ModelExtech RH25 Heat Index Psychrometer Pen
Dew Point Range−108.4 °F to 122 °F (−78 °C to 50 °C)
Dew Point Resolution0.1 °F / °C
Heat Index Range−50.8 °F to 401 °F (−46 °C to 205 °C)
Heat Index Resolution0.1 °F / °C
Relative Humidity Range0 %RH to 99.9 %RH
Relative Humidity Resolution0.10 %RH
Relative Humidity Accuracy±3 %RH
Air Temperature Range−4 °F to 122 °F (−20 °C to 50 °C)
Air Temperature Resolution0.1 °F / °C
Air Temperature Accuracy±1 °F / ±0.6 °C
Wet Bulb Range−4 °F to 122 °F (−20 °C to 50 °C)
Wet Bulb Resolution0.1 °F / °C
WBGT Range−13 °F to 130 °F (−25 °C to 54.5 °C)
WBGT Resolution0.1 °F / °C
CertificationsCE
Dimensions140 mm × 35 mm × 18 mm (5.5 in × 1.4 in × 0.7 in)
Weight50 g (1.8 oz)
Power Supply1 × CR2032 lithium coin cell (1.5 V)
Warranty2 years
What’s Included
  • Extech RH25 Heat Index Psychrometer Pen
  • CR2032 lithium battery (pre-installed)

QUESTIONS

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