Yes. If a smoke, fire, or carbon monoxide alarm is activated by the security system, Alarm.com-connected thermostats automatically set to OFF mode. This is done to prevent circulation of smoke and poisonous gas and to avoid damage to the HVAC system.
This setting is referred to as the thermostat Fire Safety rule. It is enabled by default and is highly recommended for all Alarm.com systems with a thermostat attached.
Note: If the thermostat is shut off using the Fire Safety rule, it will not be turned back on automatically after the smoke, fire, or CO alarm clears. The thermostat will need to be manually adjusted back to its desired mode.
If desired, the thermostat Fire Safety rule can be adjusted from the Alarm.com customer website. For more information about editing the thermostat Fire Safety rule, see Create/edit a thermostat Fire Safety rule.