Datasheet Contact Us Buy Now CO₂ Transmitter Series GMD20 for demand controlled ventilation The duct-mounted Vaisala CARBOCAP® Carbon Dioxide Transmitter Series GMD20 are specially designed for demand-controlled ventilation (DCV). They are easy to install and require no maintenance. The GMD20 transmitters use the silicon-based Vaisala CARBOCAP® Sensor. The simple structure and reference measurement capabilities make this Single-Beam, Dual-Wavelength NDIR sensor extremely stable and reliable. The CO2 concentration is measured inside the duct without risks for leaks or wrong flow direction affecting the measurement. In addition, the measurement accuracy is not affected by dust, water vapor and most chemicals. 5-year warranty is valid for instruments purchased in 2021 and beyond. The GMD20 series transmitters can be used independently, or incorporated into building energy management systems. The series consists of duct mount units GMD20 and GMD20D. Version D has a display. The duct units' compact sensor head design fits inside the ventilation duct, eliminating the risk of leaking gaskets and measurement errors. The recommended calibration interval is five years. View all our instruments for HVAC applications. Click here to download bid specs for USA. Features Leak insensitive in-duct measurement Incorporates the Vaisala CARBOCAP® sensor - the silicon based NDIR Excellent long-term stability Negligible temperature dependence Five year recommended calibration interval Warranty time 2 years + Show more Key Benefits Economical choice Using the GMD20 series transmitters ensures the best possible control of air quality and results in considerable savings in energy consumption, maintenance and recalibration costs. Downloads Datasheet (1.38 MB) GMD20 Series Carbon Dioxide Download the Datasheet Manual: GML20 LonWorks module (189.09 KB) Customer case: CO2 monitoring helps make defect-free potato chips (136.6 KB) Manual: GML20T LonWorks module (176.46 KB) Bid Specification: GMD20 Bid Specs, Duct Mount CO2 Sensor (158.34 KB) Manual: GMR20 Manual in English (57.42 KB) Technology Description: Vaisala CARBOCAP® measurement sensor for demanding environments (172.2 KB) Application Note: Challenges in HVAC CO2 Measurement (102.96 KB) Application Note: Infrared Sensor Technology and its Impact on HVAC CO2 Measurement Accuracy (191.73 KB) All downloads Customer Stories Customer case Infosys monitors indoor air with Vaisala’s HVAC sensors Best quality indoor air with Vaisala's HVAC sensors Infosys is the second largest Indian IT consulting company with 200,000 plus employees and... Read more Customer case High indoor air quality with minimum energy costs A random pattern of occupancy makes ventilation more difficult: the control system must be able to detect when ventilation is needed and to what... Read more Customer case Vaisala equips the New Children´s Hospital in Helsinki Vaisala was the honorary in-kind donator for the New Children’s Hospital that was built in Helsinki. The construction commenced already in 2014... Read more Customer case Vaisala CARBOCAP® Sensor for measuring carbon dioxide The CARBOCAP® story began in 1992, when micromechanical sensors were being intensively researched at Vaisala. The groundbreaking idea of... Read more Customer case CO2 monitoring helps make defect-free potato chips Carbon dioxide monitoring technology helps make defect-free chips. From farm to fryer, potatoes grown to make potato chips are sensitive to... Read more Need support? Sign up for news Contact us
Customer case Infosys monitors indoor air with Vaisala’s HVAC sensors Best quality indoor air with Vaisala's HVAC sensors Infosys is the second largest Indian IT consulting company with 200,000 plus employees and... Read more
Customer case High indoor air quality with minimum energy costs A random pattern of occupancy makes ventilation more difficult: the control system must be able to detect when ventilation is needed and to what... Read more
Customer case Vaisala equips the New Children´s Hospital in Helsinki Vaisala was the honorary in-kind donator for the New Children’s Hospital that was built in Helsinki. The construction commenced already in 2014... Read more
Customer case Vaisala CARBOCAP® Sensor for measuring carbon dioxide The CARBOCAP® story began in 1992, when micromechanical sensors were being intensively researched at Vaisala. The groundbreaking idea of... Read more
Customer case CO2 monitoring helps make defect-free potato chips Carbon dioxide monitoring technology helps make defect-free chips. From farm to fryer, potatoes grown to make potato chips are sensitive to... Read more