Learn about carbon monoxide levels in your home

Google Nest Protect sounds an alarm and sends a message to your Nest app when it detects that carbon monoxide levels become dangerous. Carbon monoxide becomes dangerous based on how high levels are in the air, and how long you’re exposed to those levels.

The danger of carbon monoxide (CO) depends on a number of variables like the amount of CO in the air, how long you were exposed to that level, and your health and level of activity. CO poisoning can result from being around high levels of CO for a short amount of time, or lower levels of CO for a longer amount of time.

Nest Protect alerts you when CO reaches emergency levels, so you know to move to fresh air. Once the carbon monoxide has cleared, these messages will also include peak CO levels, in parts per million (ppm).         Learn more about the symptoms of CO poisoning > When Nest Protect is sounding the alarm, CO has reached an emergency level, and you should move to fresh air - even if the level seems low. CO levels may continue to rise rapidly after the alarm is triggered, so the CO level shown should not be viewed as the current level of CO in your home. It is important that you always respond to a CO emergency by evacuating the house and calling 911.          What should I do if carbon monoxide is detected in my home >

Nest Protect will send you a message in the Nest app telling you the approximate CO level that set off the alarm and how long it has been detected. The concentration of CO in the air is measured in parts per million (ppm).

After the event, Nest Protect will tell you the highest level of CO that it detected. This is the peak CO level. You can also find the peak CO level in Protect History.          How to view Nest Protect’s Safety History > After the emergency, this information can be used by a fire safety professional, or an experienced technician, to help identify the source of the CO. Nest Protect is not a low-level carbon monoxide monitor and will alert you to carbon monoxide only in a Heads Up or Emergency Alarm event. For more information about alarm thresholds under American National Standard ANSI/UL 2034, see the Carbon Monoxide (CO) Precautions section in your Nest Protect User’s Guide. Individuals with certain medical problems should consider using detection devices with lower COHb alarming capabilities and consider warning devices which provide audible and visual signals for carbon monoxide concentrations under 30 ppm.

For further information, please consult a qualified medical professional or see the World Health Organization’s document on pollutants.