Back to product search

Vaisala GMW80 HVAC Transmitters

Vaisala GMW80 series is a range of carbon dioxide (CO2), relative humidity and temperature transmitters designed specifically for the HVAC and building control industry.  These low cost, yet reliable instruments are suitable for ventilation control even in building with 24/7 occupancy.  Common installs include, schools, colleges & universities, shopping centres, office blocks and gyms.  Vaisala GMW80 HVAC transmitters offer a simple and clean installation where cabling is easily hidden from view.  4-20mA and 0-10v analogue outputs allow various options for your BMS system.  Alternatively, consider the Vaisala GMW90 HVAC CO2 & Temperature Transmitters for BACNet / Modbus communication protocols.


As of 2018, Government issued bulletin BB 101 (Ventilation, thermal comfort and indoor air quality) specifically provides guidance on ventilation, thermal comfort and indoor air quality in schools.  A full copy of the document can be downloaded HERE, specific points however include:

  • Daily average concentration of carbon dioxide (CO2) of less than 1000 ppm, during the occupied period
  • Maximum concentration should also not exceed 1500 ppm for more than 20 consecutive minutes each day when the number of room occupants is equal to, or less than the design occupancy

(The above points are where mechanical ventilation is used, with allowable levels currently 500ppm higher for natural ventilated areas.  Please consult latest government guidelines and the full details given within these guidelines.  We highlight these points as guidance only).

Vaisala GMW80 HVAC transmitters offer 0…2,000ppm and 0…5,000ppm versions to accurately and reliably control ventilation within these parameters.


Vaisala GMW80 HVAC Transmitter specific model types

  • GMW86P: 0…2000ppm CO2 only with current and voltage output (inbuilt Pt1000 temperature sensor)
  • GMW86PK5: As GMW86P, except 0…5000ppm measurement range
  • GMW83RP: CO2+RH with Voltage only outputs (inbuilt Pt1000 temperature sensor)
  • GMW83DRP: As GMW83RP with display
  • GMW83: CO2+Temperature with voltage outputs
  • GMW83A: as GMW83 with additional CO2 indicator LEDs
  • GMW83D As GMW83 with display
  • GMW84: CO2+Temperature with current output for CO2
  • GMW84S: as GMW84 with relay contact
  • GMW88: As GMW86P but with splash cover for greenhouse applications
  • GMW88K5: as GMW86P but with splash cover for greenhouse applications



Vaisala GMW80 HVAC Transmitter Specifications

  • Simple install with hidden cables and clean, elegant aesthetics
  • 18…35Vdc or 24Vac (±20%, 50/60Hz) supply
  • Relay options have a SPST (normally open) contact, max 50Vac/dc, 500mA
  • Typical uncertainty within ±[30ppm +3% reading)] in normal ambient conditions
  • Stability within approx ±[15ppm +2% reading] over 5 years
  • Suitable for indoor, dry environments.  Plastic enclosure, IP30
  • Suitable for use within 0…50°C
  • RH uncertainty within ±3% (0…80%RH), measurement range <95%
  • With proven CARBOCAP and INTERCAP Vaisala sensor technology
  • Replaceable GM10 spare part CO2 sensor module and optional 18V power supply plug available



Video: Installation of Vaisala GMW80 Series CO2, RH&T transmitters



Fluidic are a recognised partner of Vaisala CEN (Industrial division) for Scotland and the North of England. Our instrumentation engineers are product trained and able to help with instrument selection within the full range of Vaisala relative humidity and dewpoint transmitters.  Please call either office for more information (Glasgow 0141 641 5920,  Warrington 01925 572401).


  • Download Vaisala GMW80 Series Datasheets
  • Download Vaisala GMW80 Series User Manual
  • Download Vaisala GMW87 Quick Start Guide
  • Download Demand Control Ventilation Savings Application Note
  • Download How to measure CO2 application note
Enquire about this product
Your Name *
Please call either office for more information: