A Guide to Better, Safer, Greener Affordable Housing

The Federation of American Scientists has just released its latest tool to improve energy efficiency, sustainability, healthfulness, and safety in the affordable housing market.

In cooperation with six Habitat for Humanity affiliates from all over the U.S. and experts at the Florida Solar Energy Center (FSEC), Pacific Northwest National Laboratory (PNNL), and Lawrence Berkeley National Laboratory (LBL), FAS has created The High Performance Building Guide for Habitat for Humanity Affiliates.  Funded by the Building Technologies Program at the U.S. Department of Energy, the goal of this Guide is to provide Habitat’s construction partners (called affiliates) with the knowledge, resources, and basic background to make educated decisions about improving their building practices, materials and technology choices, and decision-making and planning processes.

Targeted to the needs of the Habitat for Humanity building community, this Guide features profiles and case studies of excellent Habitat affiliates, practical recommendations and steps for improving building practices and decisions, and guidance on obtaining the partners, education, and resources necessary to make the transition to higher performing housing.

Get the High Performance Building Guide on the FAS website here.

To learn more about the Guide and to read a synopsis of its contents, check out the new Earth Systems Program blog.

Virtual World Training for the Building Industry

You can meet up with friends, go shopping for high fashion clothing, browse through a fanciful New York City, and build your dream house.  You can also participate in your company’s annual conference, practice patient care in an O.R., and attend a lecture by a Harvard professor.  All in the Second Life virtual world.  And recently added to that list of activities to do in Second Life is: learn how to inspect a home built from structural insulated panels (SIPs), an advanced, energy efficient building system.

But why construct a building inspector training module in Second Life?

Both the American Clean Energy and Security Act of 2009 and in the American Recovery and Reinvestment Act of 2009 set aside billions for energy efficiency and energy savings programs and green industries.  A key aspect of these bills is the creation of “green” jobs and training workers to fill these positions, with a strong emphasis on existing home weatherization and retrofits.  After all, the building sector in the United States currently use more energy and more electricity than any other sector, and much of this energy is lost to inefficient structures with a leaky thermal envelope and poor (or no)  insulation.  Substantively reducing energy demand therefore requires a combination of constructing more energy efficient, sustainable new buildings and performing deep retrofits on existing buildings.  Doing so will save money at both the household and national levels and will decrease our nation’s carbon emissions from energy.

The federal government has appropriated money to advance the state of energy efficient housing technologies and subsidize retrofits and new construction projects.  However, neither retrofits nor new construction can take place without a well-trained workforce of architects, engineers, building professionals, tradesmen, and code officials who know how to design, built, and inspect energy efficient structures.  At present, many industry professionals have no experience with or training in how to properly utilize advanced building technologies and materials and this lack of training and experience has proven to be a huge barrier to their adoption.  And so in order to transition the building industry into a more efficient and sustainable sector, tools and programs must be rapidly developed to train industry professionals in energy efficiency theories and practical applications.

In order to train workers effectively within a short period of time, the tools must be virtually based to eliminate geographical restrictions, they must be interactive and engaging to enable learning, and they must be able to simulate scenarios and situations in the real world, promote collaboration between students and instructors, and provide the means by which to learn through problem solving and independent exploration.  And at the present time, one of the only tools available that fulfills all of these requirements is virtual world technology.

To assess the utility of virtual worlds to building industry training, the Federation of American Scientists Building Technologies Program has created a pilot training module for building inspectors that utilizes the Second Life virtual world and web-based tools.  This module educates building inspectors about how to inspect houses constructed with structural insulated panels (SIPs).  In this interactive virtual environment, building inspectors can investigate structural and architectural details, interact with animated models, click on details to obtain descriptions, CAD Images, and drawings of the detail, watch a presentation, and take a self-assessment of knowledge gained.  Through these features, users learn about the importance of energy efficiency and how to achieve a tight building envelope, constructability and code compliance issues commonly found in SIP construction, and information about SIPs themselves.

While not a fully functional pilot, initial feedback indicates that virtual worlds are indeed valuable training tools, especially when coupled with an independent web-based learning module.  By combining classroom learning with field-based learning scenarios, virtual world training improves comprehension of classroom material and shortens the in-field learning curve, thereby speeding up the training process.  And due to its web-based nature, virtual world training can allow students to be trained in areas of the country where there are few trainers or certified professionals.  As such, FAS recommends further development of virtual training modules as a solution to the need to train workers for a more energy efficient building sector.

To read the Building Technology Program’s report to Lawrence Berkeley National Lab on the training, click here.  To visit the building inspector training module in Second Life, teleport to: 142, 18, 27.

Cool Roofs: A Big Deal

In the ongoing efforts to reduce our nation’s carbon output by improving the energy efficiency of our built environment, a new old idea is shaping up to be a key player: cool roofs.  Used throughout the Mediterranean and tropical climates worldwide, the solar reflectance value (albedo) of a white or light-colored roof has been long understood—the more sunlight the roof reflects, the less the building absorbs and the easier it is to keep the building cool.

A recent report by Hashem Akbari, Surabi Menon and Art Rosenfeld titled, “Global Cooling: Effect of Urban Albedo on Global Temperature”, quantifies cool roofs’ potential impact on improving energy efficiency and slowing climate change.  The report notes that painting 100 feet2 of black roof a lighter color offsets the extra heating caused by 1 metric ton of CO2 in the atmosphere.  Scaled up to the national level, converting dark-colored roofs and pavements in urban areas around the world to lighter colors would offset the extra heating caused by 44 billion metric tons of CO2in the atmosphere, effectively offsetting over 6 years of the U.S.’s CO2 equivalent greenhouse gas output and saving the country over $1 billion per year in energy costs.

Clearly, cool roofs are a big deal.  But from a building technology perspective, just painting the roof a lighter color isn’t enough, since the lighter color only solves half of the cool roof equation.  Calculating the coolness of a roof requires measuring both solar reflectance (the fraction of solar energy reflected by the roof) and thermal emittance (the measure of a roof’s ability to radiate absorbed heat as infrared light); the most useful method available for calculating roof coolness is the solar reflective index (SRI).  This index utilizes both factors to generate a 1-100 SRI rating, where 100 indicates a roof with perfect solar reflectance and thermal emittance.  The higher the SRI, the cooler a roof will be, even in full sunlight on a hot day.

Much like the HERS index for whole house energy efficiency, this rating index is essential to meeting the goal of retrofitting and constructing new buildings with cool roofs.  Without a scientifically sound method to rate the cooling properties of various roofing materials, consumers cannot make educated decisions and the maximum cooling benefits cannot be harnessed.

And while many current cool roof materials apply the latest and most advanced technologies, from spray polyurethane foam systems to brightly-colored tiles that reflect infrared energy, our historic understanding of the relationship between color and solar reflectance retains its preeminent importance.  Lighter roofing materials keep buildings cooler than darker materials, yielding more energy efficient structures that have a lower carbon footprint and are less expensive to operate.

Resources on Cool Roofs:

Hashem Akbari, Surabi Menon and Arthur Rosenfeld, “Global Cooling: Effect of Urban Albedo on Global Temperature”, 2008.  http://repositories.cdlib.org/lbnl/LBNL-63490/

Energy Information Administration, “Emissions of Greenhouse Gases Report”, December 2008.  http://www.eia.doe.gov/oiaf/1605/ggrpt/

The Lawrence Berkeley National Laboratory (LBNL) Cool Roofing Materials Database. http://eetd.lbl.gov/coolroof/

The Cool Roof Rating Council (CRRC).  http://www.coolroofs.org/

Celeste Allen Novak and Sarah Van Mantgem, “What’s So Cool About Cool Roofs”, GreenSource, March 2009.  http://continuingeducation.construction.com/article.php?L=68&C=488&P=1

The DOE Cool Roof Calculator provides an estimate of cooling and heating savings for small to medium size facilities that purchase electricity with a demand charge and an alternative version for larger facilities. http://www.ornl.gov/sci/roofs%2Bwalls/facts/CoolCalcEnergy.htm

The EPA Cool Roof Calculator allows the designer to input specific details about a building, including heating and cooling systems as well as location and the cost of energy. http://www.roofcalc.com/RoofCalcBuildingInput.aspx

A PDF version of this document is available here.