energyperformance

Energy performance is a measure of how efficiently energy is used by a system, device, or building to deliver a required service. It encompasses the rate of energy consumption for a given output, and it can include both energy use and energy-related emissions. In buildings, energy performance describes the expected or actual energy use for heating, cooling, hot water, lighting, and appliances over a period, typically expressed as energy use intensity (EUI) in kWh per square meter per year or similar metrics.

Assessment relies on engineering calculations, simulations, and field data. Building energy models, performance simulations, and energy audits produce estimates of annual energy demand. Standards and classifications vary by region but common approaches include energy performance certificates (EPCs) or labels. The European Union uses the Energy Performance of Buildings Directive (EPBD) and EPB standards; ISO 52000 series provides a framework for energy performance of buildings. In practice, performance is verified with measured data and sometimes calibrated models.

Product energy performance includes labeling schemes that classify appliances by efficiency, with classes ranging from A to G in some regions. For buildings and products, energy performance influences financing, incentives, and regulatory compliance.

Other contexts: organizations use energy management systems to improve performance, guided by ISO 50001. Key drivers include envelope quality, HVAC efficiency, lighting, equipment efficiency, occupancy behavior, and climate.

Benefits include reduced energy costs, lower emissions, and resilience; challenges include measurement uncertainty, split incentives, and upfront costs.