Energy Efficiency


Our buildings consume more energy than industry or transportation, and we haven’t done a great job of reducing that consumption. We can do better by:

  • monitoring energy use

  • improving building commissioning

  • applying insights from building science

  • selecting innovative HVAC and building envelope technology

  • using natural ventilation and daylighting to provide low-cost alternatives to standard systems

As great as all these ideas are, they won’t be nearly as effective if we don’t engage occupants about energy use as well. Our articles look at all these strategies and more.

  • Comparing Fuel Costs


    One would think comparing the costs of different heating fuels would be simple, but figuring out the amount heat available in a given quantity of fuel-and the associated cost-can be tricky.

  • An Affordable Heat-Pump Water-Heater Retrofit

    Product Review

    AirTap is an affordable heat-pump module that can be retrofit onto a conventional electric or gas water heater. The unit has a first-hour rating of 42.5 gallons, an efficiency of 240%, and a GAMA-tested energy factor of 2.11.

  • How the Sun's Path Can Inform Design


    Designing a building with the sun in mind can help reduce both heating and cooling loads.

  • Wal-Mart Introduces Second Generation of High-Efficiency Stores

    News Analysis

    Following a long program of testing green practices in experimental stores, Wal-Mart is now building high-efficiency stores that are expected to be 25% more energy efficient than conventional stores, but critics say that's not enough.

  • 2007 Energy Bill Promotes High-Performance Buildings

    News Analysis

    Although several important provisions were stripped from the federal energy bill, key improvements to appliance standards and building energy-efficiency standards remain.

  • Solar Reflectance Index and Cool Roofs


    Understanding reflectivity and emissivity of roofing materials is important to evaluating their effect on cooling loads and the urban heat island effect.

  • EPA Partnership Focuses on Commercial Refrigeration

    News Analysis

    GreenChill, a new partnership between the U.S. Environmental Protection Agency, supermarkets, and equipment manufacturers, aims to improve refrigeration technology, save energy, and eliminate the use of ozone-depleting refrigerants.

  • Energy Metrics: Btus, Watts, and Kilowatt-Hours


    Mixing units of electric power with those of energy is a common mistake, but distiguishing kilowatts from kilowatt-hours is not that complicated, and is worth getting straight.

  • LEED Delivers on Predicted Energy Savings

    News Analysis

    Data from the U.S. Green Building Council and the New Buildings Institute shows that, although varying widely in individual buildings, measured energy savings meet or exceeds predicted energy savings for LEED buildings on average.

  • Thermal Mass: What It Is and When It Improves Comfort


    Heavy or massive objects like masonry can help improve thermal comfort, if used properly. They often don't insulate well, however.