JLW Instruments is an essential business and will remain open during the Covid-19 pandemic.

Reed Instruments > Indoor Air Quality Meters

R9900 Indoor Air Quality Meter

Regular price $359.10

SKU: R9900
Brand: Reed Instruments
Lead Time: Ships in 3-6 business days
Free Shipping
Free Shipping on orders $100 and up.

This IAQ (indoor air quality) meter simultaneously monitors carbon dioxide, relative humidity, and temperature. The R9900 is capable of automatically calculating wet bulb and dew point temperatures as well as statistical TWA and STEL averages.


  • Triple LCD display simultaneously monitors carbon dioxide (CO2), relative humidity and temperature
  • Automatically calculates dew point and wet bulb
  • Calculates statistical weighted averages of TWA (8 hour time weighted average) and STEL (15 minute short term exposure limit)
  • User adjustable audible alarm
  • Data hold, Max/Min and average functions
  • Low battery indicator and auto shut off

Included Items

  • Indoor Air Quality Meter
  • Batteries
  • Hard Carrying Case


Measuring Ranges 14 to 140°F (-10 to 60°C)
Accuracy ±0.9°F (±0.6°C)
Resolution 0.1°F/°C
Measuring Range 0 to 99.9% RH
Accuracy ±3% (10 to 90% RH)
±5% (<10% & >90% RH)
Resolution 0.1% RH
CO2 (Carbon Dioxide)
Measuring Range 0 to 5,000 ppm
Accuracy < 999 ppm: ±40 ppm
>1,000 ppm: ±5% Rdg 
Resolution 1 ppm
General Specifications
Response Time 1 sec
Display Triple LCD display
Backlit Display Yes
Dew Point / Wet Bulb Calculation Yes
Data Hold Yes
Min, Max and Avg Functions Yes
CO2 Short Term Exposure Limit (STEL) Yes (15 mins)
CO2 Time Weighted Average (TWA) Yes (8 hours)
Alarm Yes (audible)
Auto Shut-off Yes (after 20 mins/off)
Low Battery Indicator Yes
Power Supply 4 AA Batteries
Battery Life Approx. 24 hours (continuous use)
Product Certifications CE
Operating Temperature 14 to 122°F (-10 to 50°C)
Storage Temperature 14 to 140°F (-10 to 60°C)
Operating Humidity Range 10 to 85%
Dimensions 7.9 x 2.7 x 2.3" (200 x 70 x 57 mm)
Weight 6.7 oz (190g)


Environmental Monitoring in:
  • Schools
  • Office buildings
  • Greenhouses
  • Factories
  • Hotels
  • Hospitals
  • Areas where high levels of carbon dioxide are generated


Related Products
SD-9901 Data Logging Air Quality Meter
Measures Oxygen, Carbon Dioxide, Carbon Monoxide, Temperature and Humidity
This indoor air quality (IAQ) datalogger measures Oxygen, Carbon Dioxide, Carbon Monoxide, Temperature and Humidity. The SD-9901 is capable of recording readings from 3 probes simultaneously and displays measurements on a large backlit LCD. Using ...
Indoor Air Quality Meters
Reed Instruments
Sound level meters, Environmental meters, Manometers, Moisture Analyzers...
Instruments that are used every day by industrial maintenance teams, quality control departments, HVAC/R contractors, electricians and health & safety professionals among others.
Liquid error: Could not find asset snippets/mw_PO_objects.liquid