Energy efficiency is the goal of reducing the amount of energy required to provide products and services, optimizing the streamlined processes, and reducing the use of energy to produce more goods and services. In other words: produce more with less energy. Improvements in energy efficiency are generally achieved by adopting more efficient technologies or by applying commonly accepted methods to reduce energy loss.

Reducing energy use reduces energy costs, resulting in financial savings for consumers. Reducing energy use is also seen as a solution to the problem of reducing greenhouse gas emissions.

Both energy efficiency and renewable energy are said to be the twin pillars of sustainable energy policy. In many countries, energy efficiency is also seen to have a national security benefit because it can be used to reduce the level of energy imports from foreign countries and may slow down the rate at which domestic energy resources are depleted.