energyefficiency

Energy efficiency refers to reducing the amount of energy required to deliver products or services without compromising quality. It differs from energy conservation, which is behavioral changes to reduce energy use, though both contribute to lower energy demand. Energy efficiency is often described as the relationship between output and energy input; improvements increase output for a given energy input or maintain output while reducing energy input. Common metrics include energy use per unit of floor area (energy use intensity) in buildings, energy per production unit in industry, and energy per passenger-kilometer in transport.

Technologies and practices across sectors drive efficiency: in buildings, insulation, high-performance windows, heat pumps, efficient HVAC and lighting; in industry, high-efficiency motors, variable speed drives, process optimization, waste heat recovery; in transportation, lightweight materials, efficient engines, electrification and aerodynamics. Standards and labeling programs, such as energy efficiency standards for appliances, building codes, and efficiency programs, incentivize adoption. Performance is tracked through benchmarking and energy audits.

Policy tools include mandatory efficiency standards, appliance and equipment labeling, building codes, subsidies for retrofits, emissions trading, and procurement policies favoring high-efficiency equipment. Economic and environmental benefits include lower energy bills, reduced greenhouse gas emissions, improved energy security, and job creation.

Challenges include upfront costs and payback periods, the rebound effect (more efficient services leading to higher energy use), split incentives in rental housing and supply chains, and data gaps for measurement and verification, especially in developing economies.

Energy efficiency is a central component of energy policy and climate strategies, complementing decarbonization with demand-side management and technology deployment.