CO₂ Sensor Guide

Use the table below to find the specific CO₂ sensor installed in your classroom. This guide provides instructions for interpreting the readings from each type of monitor used in the CalSHAPE program.

If your sensor is not listed or if you have questions about your CO₂ monitor, please contact us at [email]

Make	Model	How to Read Your CO2 Sensor	Meet Requirements
ACI	TSENSE	By default, CO₂ concentration is shown on the screen in parts per million (ppm). The sensor can also display visual warnings based on CO₂ levels: If the CO₂ concentration exceeds a red limit (default is 1000 ppm), the screen will trigger a red warning. You can also set a yellow warning to signal when CO₂ levels are moderate. To adjust these warning thresholds: 1. On the display, you'll see two vertical columns side by side: The left column shows the label (e.g., "CO₂"), The right column shows the value (e.g., CO₂ value in ppm). 2. At the bottom of these columns, there is a rectangular box. 3. Tap the rectangular box, then tap the CO₂ label. 4. Three adjustment boxes will pop up: The top box allows you to set the yellow (moderate) limit. The middle box allows you to set the red (high) limit. Follow the on-screen instructions to enter your desired threshold values, and press Save or Set to apply the changes.	Yes
Aerosphere	CO2 Mini AQM	CO₂ concentration is shown on the LCD screen of the monitor in parts per million (ppm). How It Shows Warnings: The Aerosphere system uses three levels of CO₂ alarms: Level 1: 5,000 ppm Level 2: 15,000 ppm Level 3: 30,000 ppm Visual alarm lights on the monitor show different colors: Lights start as blue when normal. As CO₂ levels rise: Light turns yellow at about halfway to the alarm level. Then orange as it gets closer. Then red when the actual alarm limit is reached. Audible alarms also trigger: At Level 1: Beeps slowly (once per second) At Level 2: Beeps faster (twice per second) At Level 3: Beeps very rapidly (four times per second) How You Adjust the Alarm Levels: Press and hold Button F (Menu button) for about 3 seconds. The screen enters alarm level setup mode. You can use UP or DOWN buttons to adjust the alarm thresholds. Use NEXT to cycle through Level 1, Level 2, and Level 3. Press DONE to save your changes.	Yes
Airthings	Space Pro	CO₂ concentration is shown on the e-ink screen of the monitor in parts per million (ppm). Note: The unit “ppm” is not shown on the screen. Instead, the value appears above a cloud icon labeled “CO₂”.	Yes
Airthings	View Plus	CO₂ concentration is shown on the e-ink screen of the monitor in parts per million (ppm). Note: The unit "ppm" is not shown on the screen. Instead, the value appears above a cloud icon labeled "CO₂". How it shows warnings: The Airthings View uses a Glow Signal (motion-activated light) to provide air quality warnings: Green: Good air quality Yellow: Fair/moderate air quality Red: Poor air quality After waving your hand in front of the device: The Glow Signal lights up first with the corresponding color. Then, the display automatically switches to show the sensor reading(s) that are contributing to poor air quality. Note: Since the device measures multiple pollutants, a red glow is not necessarily caused by CO₂ alone — it could also indicate elevated levels of other pollutants like particulate matter. How You Adjust the Display for CO₂ and Other Readings: Open the Airthings App or Dashboard. Navigate to your device's Settings. Select Display Setup. Choose which sensor readings (like CO₂, Temperature, Humidity) you want shown on the screen. Save the changes — the screen updates automatically within a few minutes	Yes
Alerton	MS4-THC	Press either the LEFT or RIGHT arrow buttons on the unit to scroll through the Detail Screens. The Microset 4 has several Detail Screens, including: Temperature, Humidity, Lights, Windows, and Air Quality. Continue pressing LEFT or RIGHT until you reach the Air Quality screen. On the Air Quality screen, the current CO₂ concentration will be displayed as: value ppm where "value" represents the measured CO₂ level in parts per million. Note: The unit "ppm" is shown next to the number, although the "CO₂" label appears separately under the Air Quality section.	Yes
Aranet	Aranet4	The CO₂ concentration is displayed directly on the Aranet4’s e-ink screen as a large number in the center. This number represents the CO₂ level in parts per million (ppm), although the unit “ppm” is shown in small text below the number alongside the “CO₂” label. The device also uses color-coded zones to indicate air quality, and if CO₂ levels become high, the display inverts — the background turns black and the numbers turn white — as an additional visual warning. Green indicates good air quality (below 1000 ppm), Yellow indicates moderate air quality (between 1000 and 1400 ppm), Red indicates poor air quality (above 1400 ppm, where screen color inversion occurs). The device also includes an audible buzzer that can be configured to sound when CO₂ levels exceed your chosen thresholds. To enable or customize the buzzer: Open the Aranet Home app and pair it with your Aranet4 via Bluetooth. Go to the device settings section. Enable the buzzer and adjust the CO₂ threshold values at which the buzzer will activate. Save your settings — changes are applied to the device immediately.	Yes
Automated Logic	ZS PRO with CO2	Press the information button on the left side of the device — it’s labeled with a lowercase i inside a circle. Keep pressing it to cycle through the available data screens. When you reach the CO₂ screen, the display will show the current CO₂ level, labeled as “CO₂” in ppm. Note: If the CO₂ value doesn’t appear, the sensor may not be configured to show it.	Yes
Autopilot	APCEMDL	The CO₂ concentration is displayed directly on the LCD screen of the device in real time. The CO₂ value appears as a large number in the center of the screen, labeled clearly with “CO₂”. How to Enable or Disable the CO₂ Alarm (Buzzer) Press the MENU button to enter the main menu. Use the buttons to scroll to the ALARM option. Press ENTER to select it. Use UP or DOWN to toggle between ON and OFF. Press ENTER again to confirm. When the alarm is enabled, a bell icon appears on the screen. If disabled, a muted bell icon is shown. The alarm sounds when CO₂ levels go above a preset threshold, which is typically within the 800–1200 ppm target zone (the default "home" setting).	Yes
Bard	S8403-067	The CO₂ concentration is shown directly on the screen in parts per million (ppm).	Yes
Capitol Energy Systems	TCW48	The LCD screen displays the current CO₂ status as: “CO₂ Low” when levels are below 1100 ppm “CO₂ High” when levels exceed 1100 ppm When CO₂ is high, the backlight flashes continuously as a visual alert. Note: The actual numerical CO₂ value (in ppm) is not shown on the screen. Instead, the status is given as either "Low" or "High" based on the 1100 ppm threshold.	CO2 value not displayed on screen (indicator for high value)
Carrier	33ZCT55CO2	The sensor does not have a built-in display and therefore does not show CO₂ values directly on the device. All readings must be accessed through analog output or a connected building management system.	CO2 value not displayed on screen (no indicators)
Carrier	IAQ1-D-4	The IAQ Desktop Display shows the real-time CO₂ concentration directly on its screen as a numeric value in parts per million (ppm), alongside other air quality measures. How the Display Reacts to CO₂ Thresholds If the CO₂ concentration exceeds the threshold you have set, the text color for the CO₂ measurement turns red on the screen. The thresholds can be customized through the settings menu. How to Set or Adjust CO₂ Thresholds Tap the Settings icon on the screen. Tap the Units icon. Enter your PIN (set during the device’s first-time setup). Scroll to CO₂ and set the desired threshold limit (in ppm). Tap the Back icon to save and exit.	Yes
Carrier	ZS2-C-CAR	The sensor does not have a built-in display and therefore does not show CO₂ values directly on the device. All readings must be accessed through analog output or a connected building management system.	Yes
Carrier	ZS2P-C-CAR	It has a small display screen that can cycle through different environmental values, including CO₂, if CO₂ sensing is enabled by the controller’s configuration. How you access CO₂ on ZS2P-C-CAR: Press the Information (i) button to cycle through available values. If the sensor is configured to measure CO₂, the screen will show a numeric CO₂ concentration, typically in ppm (though “ppm” may not be explicitly shown). The control program determines exactly what values and units appear.	Yes
Carrier	Venostat 8002	The CO₂ concentration is shown directly on the screen in parts per million (ppm).	Yes
Delta	eZNS-T100C	The CO₂ concentration is shown directly on the screen in parts per million (ppm).	Yes
Delta	EXNT-T331	The CO₂ concentration is shown directly on the screen in parts per million (ppm).	Yes
Delta	EXNT-T331	The eZNT-T331 thermostat displays the CO₂ concentration directly on its built-in LCD screen if the device is equipped with a CO₂ sensor. The CO₂ value is shown as a numeric reading in parts per million (ppm) and appears alongside other environmental parameters such as temperature and humidity (if those sensors are included).	Yes
Dwyer	CDT-5N40-LCD-S	To read the CO₂ value: The value displays automatically based on how the unit is configured. No buttons need to be pressed during normal use. If the screen is showing something else (e.g., temperature), it may be set to a different display mode. You can change it via the menu. How to Set the Display to Show CO₂ Access the menu by pressing the two arrow buttons simultaneously for 5 seconds. Navigate to the “DSP” (Display Configuration) setting. Choose one of the following options: C = CO₂ only CT = CO₂ and temperature CH = CO₂ and humidity (CDTR only) Save the setting and exit the menu.	Yes
Forensics	FD-CO2000	The FD-CO2000 CO₂ monitor displays the real-time CO₂ concentration directly on its LCD screen in parts per million (ppm). Visual Air Quality Indicators Alongside the numeric CO₂ reading, the monitor provides simple comfort indicators using facial icons: A happy face signifies good air quality, A neutral face indicates moderate conditions, A sad face alerts that CO₂ levels are elevated. Alarm Settings and Customization Users can also set their own CO₂ alarm thresholds: Press the Menu button on the side of the device. Navigate to the Alarm Settings icon. Press Enter, then use the Up and Down buttons to adjust the low and high CO₂ alarm points. By default, the monitor triggers: A low alarm at 800 ppm, and A high alarm at 1200 ppm. When CO₂ levels exceed the set thresholds, the device will alert the user according to the selected settings.	Yes
GZAIR	1200P	CO₂ Display and Visual Indicators The GZAIR 1200P CO₂ monitor displays the real-time CO₂ concentration directly on its LCD screen in parts per million (ppm). The monitor also uses simple visual indicators to reflect indoor air quality: A green LED indicates good air quality (CO₂ below the low threshold), A yellow LED signals moderate levels (between low and high thresholds), A red LED alerts when CO₂ exceeds the high threshold. Alarm Settings and Customization Users can set custom CO₂ alarm thresholds to receive alerts when CO₂ levels move beyond desired limits: Press the MENU button on the side of the device. Navigate to the Alarm Settings using the arrow keys. Press ENTER to open the setting. Use the Up/Down buttons to adjust both the low and high CO₂ alarm points. Press ENTER again to save your settings. By default, the monitor triggers: A low alarm at 800 ppm, and A high alarm at 1200 ppm. If the high threshold is exceeded, the monitor will display a red warning and sound a buzzer unless muted in the settings.	Yes
GZAIR	1300P	The CO₂ monitor displays the real-time CO₂ concentration directly on its LCD screen in parts per million (ppm To help users quickly assess air quality, the monitor features a simple LED-based color indicator system: A green light indicates good air quality, A yellow light signals moderate CO₂ levels, A red light warns of high CO₂ concentrations. Alarm Settings and Customization Users can also configure custom CO₂ alarm thresholds to trigger visual or audible alerts when limits are exceeded: Press the MENU button to enter the settings menu. Navigate to the Alarm Settings using the arrow buttons. Press ENTER, then set the low and high alarm points using the Up and Down buttons. Press ENTER again to confirm and save your settings. By default, the monitor activates: A low-level alert at 800 ppm, and A high-level alert at 1200 ppm. When the high alarm is triggered, the device will activate an audible buzzer and a red LED unless these features have been turned off by the user.	Yes
Honeywell	HTRAM	The Honeywell Transmission Risk Air Monitor (HTRAM) displays the real-time CO₂ concentration directly on its LCD screen, measured in parts per million (ppm). The value appears automatically after a brief startup period (about 1 minute), with no need to navigate menus or press buttons during normal operation. To help users quickly assess indoor air quality, the device uses color-coded LED indicators: Green: CO₂ levels below 800 ppm Yellow: CO₂ levels around 800 ppm Red: CO₂ levels above 1100 ppm Risk Settings and Alarm Customization The device comes preloaded with three activity-based risk settings: Low Activity (e.g., reading, quiet talking) Medium Activity (e.g., eating, talking) High Activity (e.g., exercising, running) These settings influence how the device evaluates risk at specific CO₂ levels. For example: In Low Activity mode, 800 ppm may trigger yellow. In High Activity mode, 800 ppm could already indicate red-level risk.	Yes
Honeywell	TR42-CO2	How to Access CO₂ Reading If CO₂ is set as the home screen value: the ppm value is shown directly without any button press. If a scrolling screen is enabled: CO₂ will appear after cycling through the other configured readings (temperature, humidity, etc.). You can also press both Up and Down buttons simultaneously to open the MORE menu, where CO₂ can be viewed directly.	Yes
Honeywell	C7632	The sensor does not have a built-in display and therefore does not show CO₂ values directly on the device. All readings must be accessed through analog output or a connected building management system.	CO2 value not displayed on screen (no indicators)
Honeywell	C7233	Reading CO₂ Data If your model includes a white LED display (e.g., C7233A1008), the real-time CO₂ concentration is shown directly on the screen in parts per million (ppm). No button-pressing or menu navigation is required — the CO₂ value remains continuously visible. If your model does not include a display (e.g., C7233A1016), the CO₂ value cannot be read directly from the device. Alarms and Visual Indicators All models feature a red LED alarm light: The red LED turns on when CO₂ levels exceed a preset threshold (e.g., 800, 1000, 1100, or 1200 ppm). The LED automatically turns off once the CO₂ concentration drops 100 ppm below the set threshold.	Yes
Honeywell	C7232	The CO₂ concentration is shown directly on the screen in parts per million (ppm).	Yes
Johnson Controls	NSB8BTC240	The CO₂ value is displayed numerically in the upper portion of the screen, typically above the temperature reading. It is clearly labeled with “CO₂,” followed by the concentration in parts per million.	Yes
KMC	STE-9301W	The CO₂ concentration is displayed on the lower line of the screen in parts per million (ppm). It may rotate with other values such as humidity, outside air temperature, or time. The reading is labeled with the unit “PPM” next to the numeric value.	Yes
Network Thermostat	X7	The CO₂ concentration is shown in the upper-left corner of the screen in parts per million (ppm)	Yes
Network Thermostat	X7C	The CO₂ concentration is shown in the upper-left corner of the screen in parts per million (ppm)	Yes
Pelican	TC3	The CO₂ concentration is displayed directly on the thermostat screen. To view it: Tap "Touch to Adjust" on the home screen. Then tap the information (ⓘ) icon in the upper-right corner. On the Info Page, you’ll see “CO₂ Sensor Reading”, which shows the current CO₂ concentration in parts per million (ppm).	Yes
Pelican	TC4	The CO₂ concentration is displayed directly on the thermostat screen. To view it: Tap "Touch to Adjust" on the home screen. Then tap the information (ⓘ) icon in the upper-right corner. On the Info Page, you’ll see “CO₂ Sensor Reading”, which shows the current CO₂ concentration in parts per million (ppm).	Yes
Pelican	TS250	It does not display the CO₂ concentration directly on the thermostat screen. All values must be accessed through the connected BAS system.	CO2 value not displayed on screen (no indicators)
Price	CO2/RH LCD	The CO₂ concentration is displayed on the main LCD screen, labeled clearly as “CO₂” followed by the numeric reading, and is expressed in parts per million (ppm).	Yes
Senva	AQ2W	By default, the CO₂ concentration appears in the lower right corner of the screen, labeled clearly with the value in parts per million (ppm). If CO₂ is not displayed You can manually configure the screen to show CO₂ data by following these steps: Press the Enter button once to access the Setup Menu. Navigate to Display Settings Use the arrow keys to scroll to the “Display” menu. Press Enter again to enter the display configuration settings. Set CO₂ as a Display Parameter You can set the CO₂ value to appear in one or more areas of the screen: Center of the Display: Go to Settings > Display > Center Select CO₂ to show CO₂ reading (in PPM) prominently in the center. Corners of the Display: You may also choose Upper Right, Lower Left, or Lower Right via: Settings > Display > [Corner Location] Then choose CO₂.	Yes
Shiantech	SA120P	The CO₂ reading appears in the main CO₂ reading area and is displayed as a numeric value measured in parts per million (ppm). Alarms and Visual Warnings If the CO₂ level exceeds the high alarm point, two things happen: A buzzer alarm sounds (if not muted), The red LED indicator turns on. If the CO₂ level is between the low and high alarm points, a yellow LED turns on. If the CO₂ level is below the low alarm point, a green LED stays on. Buzzer Mute/Unmute: There is an icon showing whether the buzzer is active. You can mute or unmute it through the menu. You can customize the high and low CO₂ alarm points by using the menu: Press the MENU button to activate the menu bar, Navigate to Alarm Settings, Adjust High Alarm and Low Alarm points according to your needs.	Yes
Siemens	QPA2284	The display will automatically show the CO₂ concentration during the cycle. The displayed values include: • Temperature, • Relative humidity (if present), • CO₂ concentration, • Occupied/unoccupied status. Each parameter is shown one at a time, so you’ll briefly see the CO₂ ppm value flash onto the screen as it rotates. The CO₂ reading is labeled as CO₂ and shown as a numeric value (e.g., 742 ppm).	Yes
Telaire	T8100-D-R	The CO₂ concentration is shown directly on the screen in parts per million (ppm).	Yes
Trane	X13790422010	It does not have a built-in display — you cannot see the CO₂ concentration directly on the device itself. How CO₂ Data Is Accessed The CO₂ concentration is output through an analog signal (such as 0–10 VDC or 4–20 mA) that corresponds to a typical CO₂ range (usually 0–2000 ppm). To read the CO₂ value, it must be connected to: A building automation system (BAS), Or a thermostat/controller capable of interpreting the analog signal and displaying it separately.	CO2 value not displayed on screen (no indicators)
Vaisala	GMW83D	CO₂ concentration is displayed automatically, labeled as CO₂. The reading is given as a numeric value and measured in parts per million (ppm). Air Quality Indicator: There’s a simple air quality text status based on CO₂ concentration, shown along with the numeric value: Good: 0–800 ppm Fair: 800–1200 ppm Poor: >1200 ppm	Yes
Veris	CW2TAXA	The CO₂ value appears as a numeric reading under the "CO₂" label. The unit measures CO₂ in parts per million (ppm), although the “ppm” text may not always be shown explicitly next to the number. The CO₂ Stoplight Mode provides color-coded background changes on the touchscreen based on CO₂ levels: Green: CO₂ less than 1000 ppm → Good air quality. Yellow: CO₂ between 1000–1499 ppm → Moderate air quality. Red: CO₂ between 1500–10,000 ppm → Poor air quality. Thresholds are user-adjustable: You can manually change the yellow and red limit values from the menu, in 10 ppm increments. A long press on the +/- buttons allows faster adjustments. Default Settings: Yellow warning at 1000 ppm Red warning at 1500 ppm	Yes
Veris	CWV2	You cannot view the CO₂ level directly on the sensor itself. To read the CO₂ data, you must connect the sensor to: • A controller, • Or another external display or monitoring device that can interpret the analog signal into ppm values.	CO2 value not displayed on screen (indicator for high value)
Viconics	VT8650U5000B-C02	The CO₂ value is displayed numerically with the label “CO₂” and the value in parts per million (ppm). Important: The CO₂ reading does not always show by default — it depends on whether the CO₂ Display setting is enabled. To make sure CO₂ appears: Press and hold the bottom right of the screen for 3 seconds to enter Setup. Navigate to Display Settings. Set CO₂ Display = Enabled. CO₂ readings will now show on the home screen, alongside temperature and humidity.	Yes
XCSpec	AQ Indoor	The XCSpec AQ Indoor does not display the CO₂ concentration numerically on the device. To see the CO2 reading, download the "AQ Indoor Mobile App" and scan the QR code on the sensor. It also uses LED indicator lights to show general air quality status related to CO₂ levels. How CO₂ Status Is Shown There are LED lights labeled for: CO₂ (left side), Air Flow (center), Wi-Fi or system status (right side). For the CO₂ indicator: The light changes color based on CO₂ concentration: Green LED: Good CO₂ levels (safe air quality). Yellow LED: Moderate CO₂ levels (borderline air quality). Red LED: High CO₂ levels (poor air quality).	CO2 value not displayed on screen (indicator for high value)