Efficient Power Supplies

Published / by EnergyEfficianado

Efficiency of Power Supplies in the Active Mode

Power supplies are one of the crucial building blocks of a modern society, converting high-voltage alternating current (AC) into low-voltage direct current (DC) for use by the electronic circuits in office equipment, telecommunications, and consumer electronics. Over 2.5 billion AC/DC power supplies are currently in use in the United States alone. About 6 to 10 billion are in use worldwide.

While the best power supplies are more than 90% efficient, some are only 20 to 40% efficient, wasting the majority of the electricity that passes through them. As a result, today’s power supplies consume at least 2% of all U.S. electricity production. More efficient power supply designs could cut that usage in half, saving nearly $3 billion and about 24 million tons of carbon dioxide emissions per year.

The Purpose of This Web Site

This Web site was created by EPRI and Ecova to initiate a global dialogue about energy efficient power supplies. Our focus here is particularly on the issue of energy consumption in the active or “on” mode of product operation. According to our research so far, nearly 75% of all the energy used by power supplies occurs in active mode. For those interested primarily in standby power consumption or other low-power modes, please visit Lawrence Berkeley National Laboratory’s Web site on that topic at http://standby.lbl.gov.

In 2003, the California Energy Commission’s PIER (Public Interest Energy Research) program has funded Ecova and EPRI to assess the efficiencies of modern power supplies and recommend strategies for improving them. An open exchange of design information, test methods, measured results, and other related documents is essential to that project’s success, tapping the best information available from manufacturers, government agencies, utilities, and product users.

Ecova and EPRI continue to work on a variety of other power supply and whole-product efficiency initiatives in the U.S., Europe, and Asia, described in more detail under Projects and at www.efficientproducts.org website. Our goal in every case is to accelerate the market for more energy-efficient products, saving energy and preventing pollution.

How You Can Get Involved

  • Power supply manufacturers: Review and comment on the proposed test methods, browse efficiency test reports on power supplies, read about the design competition held in 2004, and contribute news clips on your latest efficient product offerings.
  • Electronics assemblers: Compare the efficiency of the power supplies you use to the models in our test reports.
  • Utilities: Join our efforts in improving efficiency of power supplies, find out how utilities participate in the 80Plus Program and try the calculators to see how much energy a more efficient power supply will save.
  • Government agencies: Check efficiency policies for the latest news on labeling and incentive programs, procurement strategies, and mandatory standards.
  • Consumers: Take a look at the Efficiency Opportunities and the Power Supply Efficiency Policies to learn more about the developments that are happening in the power supply efficiency research.

For more resources on efficient power supplies and other savings visit https://www.linkedin.com/in/couponcoder/

energy efficient home

Green Homes and Their Construction

Published / by EnergyEfficianado

With the rise of the housing market and the desire to be environmentally friendly, individuals are putting more time and money into constructing energy-efficient, renewable homes. It is estimated that single family “green” homes represent approximately 1/3 of the housing market. They are designed to better conserve water and energy with renewable and safe materials, decreasing the impact on the environment and improving personal health. LEED, or The Leadership in Energy and Environmental Design, is a program responsible for certifying green buildings based on environmentally friendly and efficient building methods.

Water Conservation

Typical green homeowners experience a water savings of approximately 20%. This can be accomplished in a variety of ways by installing green plumbing systems or purchasing water-efficient appliances and fixtures. Green homes may be designed to conserve more water by recycling grey water – or waste water that is not contaminated with fecal matter–for irrigation systems. One of the simplest methods for achieving this is to deviate water from laundry washing machines straight into the garden or yard. Many experts advise having a professional install this system, as there are filtering processes that are put in place to make grey water irrigation as safe as possible.

Cisterns may also be installed to collect rainwater, which can be filtered passively and used for irrigation, or can be further filtered and safe to drink. Typically, gutters and drains from rooftops will be rerouted into large collection barrels for maximum accumulation. Passive filtration systems often use materials such as sand and charcoal to filter large particles and reduce chlorine and harmful compounds. Charcoal also assists in removing the taste and smell from rainwater. Added filtration can come from personal, high-end water filters or from systems installed within the home that can separate potable (for ingestion) and non-potable water.

Additionally, green plumbing systems can be installed to reduce water consumption and improve efficiency in the home. Placing a hot water heater in a central location can diminish the amount of heat loss from the water when traveling from the heater. There are also eco-friendly and cost-effective alternatives to PVC and copper piping that produce no negative byproducts during manufacturing and are better insulated and more durable. Together, there are many options for green and traditional homeowners to improve the capability and safety of their plumbing systems, including replacing the delivery system of the water.

Water-efficient fixtures such as faucets, shower heads, and low flow toilets may be installed to continue to regulate water consumption. These fixtures range in a variety of designs and functions and can be easily installed after construction as well. Additional appliances such as dishwashers and laundry machines have energy and water-efficient options for any homeowner.

Energy Conservation

To add to the overall cost effectiveness and renewable design, green homes use both passive and active design techniques to maintain energy efficiency. Heating and lighting are two principal consumers of electricity in a home. To counter this, many builders attempt to face the home south to increase the amount light and heat in the home. Many builders also plan with natural insulation in mind, which can decrease the amount of heat lost through radiation. A common way to accomplish this is to build the home into a hill or cover it with dirt and plants, which maximizes both yard and growing space. Energy efficient, well-insulated doors and windows are another popular passive strategy to reduce heating costs. Larger windows also allow more light to enter the home. Less square footage and more efficient layouts further improve passive heating and cooling. It is estimated that these expenditures can be lowered by 50% or greater with green construction, and LEED certified homes are designed to use 30-60% less energy overall.

Further measures to reduce energy consumption involve using renewable energy sources. Typically, these measures consist of solar, photovoltaic, or geothermal systems to provide renewable energy. Location of the home, however, has a huge impact on these sources. A heavily forested plot can significantly reduce sun exposure, as can placing panels on a home in an area that is overcast most of the year.

Healthier Materials

Green homes are also advertised as being healthier due to the use of environmental and health-friendly building materials. LEED-certified homes require non-toxic building and finishing materials, which may be present in many older homes. Paint, fixtures, carpet, and wood finishes may have unhealthy constituents such as lead and formaldehyde (sometimes found in manufactured wood). LEED certifications also require proper ventilation and high-efficiency air filters, reducing allergens in the air and improving air quality overall. Extra measures to reduce mold and mildew from the home also reduce allergens in the home. As noted above, alternatives to current piping may also have a lesser impact on health. The options vary, but many of these products are available for green homes and traditional homes, alike.


Overall, green homes are a smart choice for buyers looking to save money in the long run, as the durability of these homes reduces maintenance costs over time. Average upfront costs are estimated at 2.4% compared to a traditional home. Energy and water-efficient appliances are also a greater immediate expense, but may reduce bills in the long run. Adding renewable energy sources requires an even greater payout; solar hot water heaters, for example, run from $4,000 to $9,000, compared to a $700 price tag for a conventional heater. These heaters, however, can halve the buyer’s water heating costs. Furthermore, the Earth Advantage Study reported that green-certified homes sell for 30% more than conventional homes, which may increase as the demand for environmentally-friendly products becomes more apparent, while the average actual cost per square foot is roughly the same.

Overall, much can be done to improve efficiency and decrease the environmental impact of construction. With construction accounting for almost 40% of national CO2 emissions, LEED-certified buildings consume less energy, water, and, according to the United States Green Building Council, have helped to keep more than 80 million tons of waste from landfills. With this positive impact, it is no wonder that more LEED-certified green homes are being built and the resale is so high. The decision to purchase or build a green home is up to each individual, but even if the final choice is for a traditional home, the options and practices that can reduce waste, bills, and environmental impact can still be put into place.