Model-AQH-20

Supported Applications

The Model AQH-20 Handheld Indoor Air Quality Meter reduces the number of instruments a contractor has to carry by measuring carbon dioxide concentration, air temperature, and relative humidity in a single device. A large backlit LCD shows all three parameters simultaneously, and the meter can display dew point or wet bulb temperature in place of ambient temperature.

• Indoor air quality checks, reading CO2, temperature, and humidity together during walk-throughs.
• HVAC and ventilation troubleshooting, with user-selectable engineering units and minimum, maximum, and average readings.
• Spot measurements and logging comparisons, aided by a hold function and an audible alarm.

For accurate readings, the CO2 sensor should be calibrated in fresh outdoor air that is well ventilated and in good weather conditions; it should not be calibrated in areas with high CO2 concentrations such as crowded areas. When the meter experiences a large variation in environment, it may take 30 seconds to respond.

Operating Conditions & Performance

The AQH-20 uses a non-dispersive infrared (NDIR) CO2 sensor alongside temperature and humidity sensing:

• CO2: range 0 to 2000 ppm; accuracy ±30 ppm ±5% of reading; resolution 1 ppm.
• Temperature: range 14 to 140°F (-10 to 60°C); accuracy ±0.9°F (±0.6°C); resolution 0.1°F (0.1°C).
• Relative humidity: range 0.0 to 99.9% RH; accuracy ±3% RH (10 to 90%), ±5% (0.0 to 9.9% or 90 to 99.9%); resolution 0.1% RH.
• Response time: CO2 < 30 seconds; temperature < 2 minutes; humidity <10 minutes.

The display shows four digits for temperature/CO2 and three digits for humidity, and warm-up time is 30 seconds. The meter operates from 32 to 122°F (0 to 50°C) at 0 to 95% RH (non-condensing) and is powered by four 1.5 V AA alkaline batteries, included and user replaceable. It weighs 6.76 oz (200 g) and carries CE approval.

Configuration Options

The AQH-20 is a single-model meter, so every unit provides the same three-parameter measurement set — CO2 from 0 to 2000 ppm, temperature from 14 to 140°F (-10 to 60°C), and humidity from 0.0 to 99.9% RH — along with the same backlit LCD, NDIR CO2 sensor, and selectable dew-point/wet-bulb display. There are no separate capability tiers within the series.

Key Product Differences

The model chart lists a single instrument:

• AQH-20 — CO2 range 0 to 2000 PPM, humidity range 0.0 to 99.9%, temperature range 14 to 140°F (-10 to 60°C).