What is meant by latent heat?

Latent heat refers to the heat energy that is either absorbed or released by a substance during a phase change without a change in temperature. This phenomenon occurs during transitions such as melting, freezing, vaporization, and condensation. For example, when ice melts into water, it absorbs heat, known as the latent heat of fusion, which allows the ice to transition to a liquid state without an increase in temperature. Similarly, when water vapor condenses into liquid, it releases the same amount of latent heat, which is crucial for many processes in nature and in various applications, such as HVAC systems. Understanding latent heat is essential in building science as it impacts thermal comfort, energy efficiency, and overall building performance.