Which factor is most significant when figuring the electrical service demand for an office building?

The significance of lighting load in determining the electrical service demand for an office building stems from its consistent and predictable use. In commercial environments like offices, lighting is critical not only for visibility but also for the overall working environment. It often contributes a substantial portion of the total energy consumption and has specific local codes and guidelines that dictate minimum requirements.

Most office buildings operate during daylight hours with artificial lighting supplementation, making the lighting load a reliable measure for service demand calculations. Moreover, lighting typically has a higher demand factor compared to heating, cooling, or receptacle loads, meaning that a larger proportion of the lighting load will usually be in use simultaneously.

While heating, cooling, and receptacle loads are also important, they may vary depending on seasonal changes, occupant behavior, and usage patterns. Therefore, the lighting load emerges as the most significant factor because it usually drives the base electrical demand that must be accounted for in the overall service capacity design.