According to the first law of thermodynamics, what is true about heat as a form of energy?

The first law of thermodynamics, also known as the law of energy conservation, states that energy cannot be created or destroyed, only transformed from one form to another. This principle applies to all forms of energy, including heat. In a closed system, the total amount of energy, including heat energy, remains constant over time. Therefore, any heat added to a system must come from another form of energy, and any heat lost by the system must go somewhere else, typically into the environment or to another system.

This concept is foundational in understanding how energy works in residential air conditioning systems, as it governs the relationships between heat, work, and energy transfers within the system. Because heat is a form of energy, and all energy must adhere to the first law of thermodynamics, it cannot be created or destroyed in the context of thermal processes. This understanding is crucial for properly managing and troubleshooting heating and cooling systems.