Literature summary: heat balance accounts for rates of energy transfer. If solar gain, conduction, outdoor-air exchange, people, lighting and equipment together add heat faster than the cooling system removes it, zone temperature rises. When the rates approach balance, temperature may stabilize even though the space remains above the desired condition.
The envelope, glass, roof, doors and ventilation connect indoor conditions to weather. Internal gains can change just as sharply: occupied kitchens, process equipment, lighting and electronics can shift the balance without a mechanical failure. Report heat rates in watts or kilowatts; installed U.S. equipment may also show Btu/h, where 1 kW is approximately 3412 Btu/h.
Nominal refrigeration capacity is not identical to heat removed from each occupied zone. Airflow, return paths, duct leakage, controls, coil condition and heat rejection determine how much useful cooling reaches the complaint area under the observed condition.
Buildings store heat in air, contents and assemblies, so timing matters. A short snapshot may miss solar lag, occupancy peaks, control staging or recovery after shutdown. A defensible investigation ties observations to time, weather, use and operating state.