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Energy Efficiency and Conservation
Energy conservation refers to reducing energy use through behavioral changes, improved efficiency, and the elimination of unnecessary energy waste. Energy efficiency means using less energy to perform the same task or achieve the same result, thereby reducing energy consumption, costs, and environmental impacts. Examples include energy-efficient appliances, LED lighting, electric vehicles, improved insulation, and smart thermostats. Building design can also conserve energy through features such as large windows for natural lighting, passive solar heating, natural ventilation, green roofs, and strategic shading that reduce the need for artificial heating, cooling, and lighting (figure \(\PageIndex{a}\)). Because the cleanest and least expensive energy is often the energy that is never used, energy conservation and efficiency are considered among the most effective strategies for reducing environmental impacts and greenhouse gas emissions.
Figure \(\PageIndex{a}\)): The Solar Settlement with the Sun Ship in the background: two PlusEnergy projects in Freiburg, Germany.The houses contain 2-3 floors and were built with ecological building materials via wooden post-and-beam construction from regional forests and prefabricated individual modules, PVC-free, and environmentally friendly insulation materials. The houses are designed for high energy efficiency, with south-facing orientation to maximize solar energy use. They follow passive house standards, including strong insulation and high-performance glazing, resulting in very low heating needs and low annual energy costs. Each home uses a ventilation system with heat recovery and is connected to a local heating network. The roofs are equipped with photovoltaic panels, creating a large solar power system for the entire site. Andrewglaser at English Wikipedia. CC BY-SA 3.0
Advances in energy efficiency have helped reduce per-capita energy consumption in the United States. As a result, Americans used less energy per person in 2024 than in 1968, even though modern lifestyles rely heavily on computers, electronics, and other technologies that consume energy (figure \(\PageIndex{b}\)).
Explore the interactive graph below showing primary energy consumption per person. Compare the United States, the global average, and one other country by selecting countries from the menu on the right. How do energy-use patterns differ among these regions? What economic, geographic, technological, or social factors might contribute to these differences?
Figure \(\PageIndex{b}\): Energy use per person interactive (measured in kilowatt-hours per person. Data source: U.S. Energy Information Administration (2026); Energy Institute - Statistical Review of World Energy(2025); Population based on various sources (2024) – Our World in Data(opens in new window) [OurWorldinData.org] | CC BY(opens in new window)
Personal Energy Conservation
Personal energy conservation can be achieved through both simple daily habits and larger investments. Low- or no-cost actions include turning off lights and electronics when not in use, unplugging devices that draw standby power, lowering water-heater temperatures, driving efficiently, and using passive solar heating and lighting, such as opening south-facing blinds during winter days. Other strategies require an upfront investment but can pay for themselves over time through lower energy bills. An energy audit can help identify where a home is losing energy and which improvements will provide the greatest benefits. Common upgrades include sealing air leaks, adding insulation, installing Energy Star–certified appliances, upgrading to energy-efficient windows, using smart thermostats, switching to LED lighting, and replacing older heating and cooling systems with air-source heat pumps (figure \(\PageIndex{c-e}\)). Together, these measures can substantially reduce energy consumption, save money, and lower greenhouse gas emissions.
Figure \(\PageIndex{c}\): Energy Star appliances use energy efficiently. Image by MoneyBlogNewz (CC-BY)
This video demonstrates how to conduct an energy audit and explains how the results can be used to reduce energy consumption, lower utility bills, and improve home comfort.
Attribution
This page was heavily revised and rewritten by Erin Rempala and contains adapted content from content originally authored by Melissa Ha and Rachel Schleiger and is licensed CC BY-NC-SA 4.0.
Melissa Ha (CC-BY-NC) and Home Energy Audits. U.S. Department of Energy. Accessed 01-18-2021. (public domain)
This page titled 7.3.7: Energy Efficiency and Conservation was last modified on Fri, 11 Sep 2026 21:01:07 GMT and is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Melissa Ha and Rachel Schleiger (ASCCC Open Educational Resources Initiative) .
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