A thermostat is a device that detects what condition?

A thermostat primarily functions by detecting temperature changes in its environment, specifically sensible temperature conditions, which relate to the air temperature that can be sensed by humans. It uses this information to regulate heating or cooling systems, ensuring that the space maintains the desired temperature set by the user.

While pressure changes, humidity levels, and airflow speed are important factors in HVAC systems, they are not the primary function of a standard thermostat. Instead, these functions might be managed by other sensors or specialized systems designed to monitor and maintain specific aspects of indoor air quality or system performance. The thermostat's key role is centered around temperature regulation, making it essential for maintaining comfort in residential and commercial settings.