Each building has an overall energy demand (also known as load): the amount of energy that needs to be available to operate the project. This includes how much heating or cooling it takes to maintain comfort (thermal loads) and how much electricity the project's equipment uses (electrical power loads, including lighting, plug, and process loads).

每栋建筑都有整体的能源需求（也称为负荷）：即项目运行所需的可用能源总量。这包括维持舒适环境所需的采暖或制冷能耗（热负荷），以及项目设备的用电量（电力负荷，包括照明、插座和工艺负荷）。

A project's peak demand is the maximum amount of thermal energy or electrical power that must be available at a specific point in time. Peak demand is when a building system must work its hardest to fulfill its function. There are several factors that impact peak demand, including timing (e.g., peak demand for a restaurant would be during mealtimes, while peak demand for an office would be during business hours) and outdoor conditions (e.g., the less comfortable the outdoor temperature and humidity level, the more work the heating and cooling system needs to do to condition the incoming air).

项目的峰值需求是指在特定时间点必须具备的最大热能或电功率。峰值需求是建筑系统为完成其功能而必须满负荷运行的时刻。影响峰值需求的因素有多个，包括时段（例如，餐厅的峰值需求出现在用餐时段，而办公室的峰值需求出现在工作时段）和室外环境（例如，室外温湿度越不适宜，采暖和制冷系统处理新风所需的能耗就越高）。