While the broad categories of EUI breakdown fall into heating, cooling, lighting, equipment, fans, pumps and hot water, below is a more detailed overview of what is covered in these categories.

//Space heating and cooling: Energy usage calculation for heating and cooling of the space based on the project details such as location, geometry, occupancy rate etc. HDD (heating degrees days) quantifies the demand for energy needed to heat a building. CDD (cooling degrees days) quantifies the demand for air conditioning to cool a building. If your location has more HDD, typically cooler climates, then heating will be your primary thermal EUI load. If your location has more CDD, typically hotter climates, then cooling will be your dominant thermal EUI load. A more detailed description is provided by the U.S. Energy Information Administration.

//Lighting: The energy consumed by both indoor and outdoor lighting for the space. Efficient fixtures, turning on the daylighting and occupancy sensors would lead to lower lighting EUI number. In addition to impacting just the lighting load, the lighting fixture also produce internal heat and lead to sensible heat gain for the cooling calculations.

//Equipment: The energy consumed by the appliances used in the space for daily operations. Examples include computers, coffee machines, refrigerators, etc. Check out this article which states the ranges for equipment power density for different building types. In addition to impacting just the equipment load, the appliances also produce internal heat and lead to sensible heat gain for the cooling calculations.

//Fans: Energy consumed by the fans used by HVAC systems for maintaining the space comfortable ventilation. Check out this article which contains the specific fan power values for various systems.

//Pumps: The pump flow energy is the auxiliary energy source whose distribution losses lead to the pump EUI numbers. Learn more about pump control inputs here.

//Hot Water: The energy spent on heating up the water, and varies based on the project use type. For example, office and hotel would have significantly different hot water energy consumption and the EUI numbers will reflect that.

For example, following is the EUI Breakdown of Medium Office building prototype by Pacific Northwest National Laboratory (PNNL) located at Atlanta, Georgia referring to ASHRAE 90.1 2016 code version: