Capitol Energy Systems TWC-48

CO2 sensors are used to control ventilation systems and monitor indoor air quality. They can be stand-alone sensors or integrated into thermostats or air quality monitoring platforms.

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Capitol Energy Systems TWC-48

Thermostat with integrated CO2 sensor for long term monitoring and demand control ventilation.

Hub Highlights:

CO2 value displayed on device. Graph of CO2 values over time available on cloud-based interface.
Connects to Capitol Energy Systems building automation system.
Excellent performance on Hub CO2 accuracy testing protocols
Includes CO2, temperature, and humidity sensors. Uses automatic background calibration.

Last Edited on: 9/8/2025

Sensor Type	Photoacoustic Manufacturer: Sensirion
Power Input	24 VAC
Outputs	2-10 VDC, Wifi to cloud-based interface
Altitude Correction Method	Unknown
Measurement Range	0-2,000 ppm
Reported Accuracy	± 45 ppm
CO2 Display	On device and web (account required)
Uses Automatic Background Calibration (ABC)	Yes

Date of Test (including warm-up period if device uses automatic background calibration)	August 12-29, 2025
Sample Size	5
Error of CO2 measurement @1100 ppm (average) (ppm)	38
Error of CO2 measurement @ 1100 ppm (standard deviation) (ppm)	23
Accuracy Category	less than ±75ppm
Noise of CO2 measurement @1100 ppm (Average) (ppm)	3
CO2 Full results	See Box Plot
Operating Power for Sensor (watts)	0.64
Operating Power for Gateway (watts)	NA
Operating Power for Sensor + Gateway (watts)	0.64
Operating Power Category	less than ±1 W
Maximum Number of Sensors per Gateway	NA

Data Collection

Sample Size

Data Source: Staff at the UC Davis Western Cooling Efficiency Center

User interface

1. Can the sensor display the CO2 level to occupants? If yes describe.

Yes - Live CO2 readings and graphed historical CO2 data available on Capitol Energy Systems TECS webpage, account required. Sensor must be connected to local wifi network.

User interface

2. Can the sensor display a visual indicator to occupants that the CO2 level has exceeded a programmed threshold? If yes, describe (what does the indicator look like, what the default thresholds are, and can the threshold be changed).

Yes - Sensor screen displays "CO2 Low" if CO2 is below 1100 ppm and "CO2 High" if CO2 is above 1100 ppm. Screen backlight flashes continuously when CO2 is high. Visual alert threshold cannot be changed.

Reporting capabilities

3. Can the sensor alert facilities (such as an email, text, or call phone application) when the CO2 level has exceeded a programmed threshold? If yes, describe (what does the indicator look like and can the threshold be changed).

Yes - Email alerts can be configured on webpage. Alert threshold can be changed.

Integration capabilities

4. Can the CO2 sensor interface with a building automation system (BAS) or demand control ventilation (DCV) system controller? If yes, describe if integration capabilities are vendor specific.

Yes - Capitol Energy Systems TECS BAS available. Also interfaces with Honeywell Jade economizer control module.

Integration capabilities

5. If sensor can interface with a BAS or DCV system controller, is additional hardware required?

Yes - Honeywell Jade economizer control module needed for DCV.

Reporting capabilities, Integration capabilities

6. How can the CO2 sensor data be logged? If proprietary software, describe (what type of account is needed, what logging intervals are available, what does it look like, and describe its capabilities including data download capabilities).

Data logged every 3-4 minutes and displayed graphically on webpage. Maximum CO2 during a user-selected date range available as a .csv download via the TECS webpage, account required. Sensor also outputs a 2-10V analog CO2 signal that can be logged separately.

Installation

7. Does the sensor require specialized software for installation? If yes, describe.

Yes - Requires proprietary webpage.

Installation

8. Does the sensor require specialized training for installation? If yes, describe.

Operation

9. Does the sensor require on-going maintenance? If yes, describe.

Operation

10. Does the sensor require service contracts for ongoing data access? If yes, describe.

Miscellaneous

11. Are there any other notes about the user experience?

Capitol Energy Systems can pre-program sensor wifi network information prior to device shipment.