Chilled mirror techniques are methods used to measure humidity in the air. This process involves cooling a mirror until moisture from the air condenses on its surface. The temperature at which this condensation occurs is known as the dew point, which helps determine the amount of water vapor present in the air. These techniques are commonly used in meteorology and HVAC systems to monitor and control humidity levels. By providing accurate readings, chilled mirror devices can help maintain comfort in indoor environments and support various industrial processes that require specific humidity conditions.