Energy conservation refers to reducing energy consumption through using less of an energy service. Energy conservation differs from efficient energy use, which refers to using less energy for a constant service. For example, driving less is an example of energy conservation. Driving the same amount with a higher mileage vehicle is an example of energy efficiency.
From more efficient appliances to better building materials, advances in residential technologies are helping homeowners save energy, and many of these technologies can trace their roots back to the Energy Department. Through investments at the early stages of technology, tougher appliance standards and collaboration with researchers at our National Labs and private companies to develop energy-saving technologies, the Energy Department is helping lay the foundation for more efficient homes. Explore the top four Energy Department inventions that are helping homeowners save energy and money — you might even find some of the innovations in your home!
Loose-Fill Fiberglass Insulation
Hidden in walls, attics and floors, insulation helps keep homes comfortable with little thought from the homeowner. In 1992, private insulation manufacturer Energy Savings Solutions, Inc., reached out to Oak Ridge National Laboratory to find ways to improve loose-fill fiberglass insulation — one of the most common types of attic insulation. After discovering that in cold climates this type of insulation resulted in heat losses of up to 50 percent, Oak Ridge researchers provided the guidance necessary to substantially improve the insulation’s performance. Oak Ridge’s findings sparked an industry-wide reformulation of loose-fill fiberglass insulation, leading manufacturers to redesign their products for better fiber dispersion. The findings also had an impact on state building codes. Minnesota rewrote its energy code to require manufacturers to label insulation based on the coldest expected winter conditions. Today, nearly 75 percent of homes use this type of improved loose-fill fiberglass insulation, and researchers estimate the changes have helped consumers in cold climates save 5-10 percent on heating costs. Looking to the future of building envelope technologies, the Energy Department is working to develop new more efficient insulation that can be added to existing homes and buildings. One such project with Industrial Science & Technology Network, Inc. focuses on using nanotechnology to develop cost-effective, environmentally friendly foam insulation that is more efficient than current technology. If successfully commercialized, the company estimates the technology could save $8 billion a year in heating and cooling costs.
Electric Heat Pump Water Heaters
Since the start of the Energy Department in the late 1970s, the Building Technologies Office has spearheaded research and development in energy-efficient residential water heating solutions, and in the late 1990s, the Department began exploring electric heat pump water heaters. This early research — plus the growing demand for more efficient water heaters spurred by the ENERGY STAR program — laid the groundwork for the electric heat pump water heater market. In 2009, Oak Ridge National Lab worked with General Electric to bring the GeoSpring water heater, the first ENERGY STAR-qualified electric heat pump water heater, to the market. Part heat pump, part conventional storage water heater, the GeoSpring water heater uses 62 percent less energy than a standard 50-gallon electric water heater. Heat pump water heater sales have skyrocketed from about 2,000 units sold in 2006 to more than 34,000 in 2012. Today, seven manufacturers offer ENERGY STAR-qualified electric heat pump water heaters under more than a dozen brand names. Based on the national average residential electricity price in 2012 (11.88 cents per kilowatt hour), electric heat pump water heaters can save homeowners about $300 a year on their energy bills.
Even with this advancement, there is still plenty of room to improve water heaters, which consume more energy than all other household appliances combined. The Energy Department continues to move water heater technology forward, most recently announcing funding for two new projects developed by America’s small businesses.
Energy-Efficient Refrigerator Compressor
Over the years, refrigerators have changed dramatically — from a box cooled by an ice block to a wi-fi-connected smart appliance. But even though fridges have gotten bigger on average and have more features, they use about 25 percent less energy than those built in 1975 — an improvement with Energy Department origins. Between 1978 and 1980, researchers at Oak Ridge National Lab and Columbus Products Company developed a fridge compressor that was nearly 50 percent more efficient than the typical compressor at the time. Manufacturers incorporated the new advanced compressor into multiple refrigerator lines throughout the 1980s and 1990s — helping save consumers $6 billion in energy costs over that same period. The advanced compressor also allowed the Department to implement more stringent energy standards for fridges in 1993 and 2001 — and now new ones that will go into effect this year. Today, more than 100 million refrigerators in homes across the country use an advanced compressor that can trace its roots to the Department’s pioneering research and development in the late 1970s. Over the past four decades, fridges have improved dramatically, consuming on average only 480 kilowatt hours of electricity a year. As manufacturers continue to look for new ways to cut the fridge’s energy use, magnetic refrigeration is one area that holds promise. Recently, GE announced it is working with Oak Ridge to develop a new type of fridge based on magnetic refrigeration, a technology that uses no refrigerants or compressors and is 20 percent more efficient than today’s technology.
Beyond Double-Pane Windows
While the invention of double-pane windows dates back to 1935, a true turning point in the technology came in the 1980s with a collaboration between the Energy Department, private industry and Lawrence Berkeley National Lab. The first breakthrough was low-emissivity (low-e) coatings — a technology applied to glazing layers that allows visible light to pass through a window while trapping heat. Low-e coatings had been around since World War II in specialty applications like oven windows, but it was initial research and development by Berkeley Lab and a start-up company, Suntek Research Associates (now called Southwall Technologies), that led to the commercialization of the technology for use in homes. In 1981, Suntek introduced the first low-e window technology on the market. By 1988, low-e windows accounted for 20 percent of window sales. Today, more than 80 percent of residential windows and nearly 50 percent of commercial windows sold every year in the U.S. have low-e coatings, saving consumers billions of dollars in energy costs. Berkeley Lab researchers continued to work with industry partners to develop even more energy-efficient window designs. By replacing the air with an insulating gas between two window panes, researchers were able to further decrease heat loss through windows in cold climates. They then added an additional glazing layer with low-e coating to create a triple-pane window with two low-e coatings and an argon and krypton gas mixture that filled the space between each pane. These highly insulating window designs can perform as well as — or even better than — a highly insulating wall, helping to dramatically reduce a building’s energy loss. The future of windows looks bright as the Energy Department continues to invest in research and development to reduce the costs of highly insulating windows and make window replacements cost-effective for consumers. One promising project is the National Renewable Energy Lab’s work on insulating window films — a clear layer of insulation that is added to existing windows. NREL estimates that the films could reduce building energy use by as much as 33 percent, creating a simple payback for window retrofits of less than one year.