CO2 card

Who it’s for

Building managers, HVAC technicians, and indoor environment teams ask “is the CO2 level in this space safe right now?” High CO2 concentration affects alertness and comfort before it becomes a health risk, so a quick-read card that flags a problem without a number lookup helps anyone monitoring a building management screen.

What it does

A ventilation sensor reporting 520 ppm shows a dark green icon and value — Good. The same card turns orange at 1100 ppm — Elevated — and deep red above 1500 ppm — Hazardous.

• Color-coded icon and value that change across four CO2 concentration levels, from Good to Hazardous
• Auto-scaling layout that fits any card size
• Last-updated timestamp showing how long ago the reading arrived
• Configurable icon, label, and color ranges
• Shows one CO2 reading at a time; it does not chart trends or compare rooms

How to set up

Data keys

Key	Role	Type	Description
co2	Main value	Timeseries	CO2 concentration in ppm; change the key name to match your device’s telemetry key

The widget ships with a simulated function datasource key labeled CO2 level, so it draws random values until you point the datasource at a device and rename the key.

To point it at your own device: open the dashboard in edit mode, open the widget’s Datasources, pick the entity or entity alias, and replace the function key with the key your device reports.

The card shows the value in ppm with no decimal places. If the key has never reported, the card displays the label and icon with an empty value, not an error.

Value ranges

Range (ppm)	Level	Color
0–600	Good	Green
600–1000	Moderate	Light Green
1000–1500	Elevated	Orange
1500+	Hazardous	Red

How to customize

• To use your own CO2 thresholds — edit Icon color ranges and Value color ranges; set the same boundaries in both so the icon and the number always agree.
• To change the icon — set Icon to any Material or MDI icon name.
• To resize the icon — change Icon size.
• To reposition the label — change Label position to top, bottom, left, or right.
• To hide the label, icon, or timestamp — turn off Show label, Show icon, or Show date.
• To switch to an absolute timestamp — turn off Last update ago in the date format settings.
• To match your dashboard’s fonts — set Value font and Label font.

Tips

• Keep Icon color ranges and Value color ranges on the same boundaries so the icon and the number always show the same level.
• Typical indoor CO2 guidelines: below 600 ppm is excellent, 600–1000 ppm is acceptable for most occupied spaces, above 1000 ppm suggests inadequate ventilation, and above 1500 ppm is a ventilation problem that needs attention.