The most recent blogs at Green Building Advisor

Pro/Con: Open-Cell or Closed-Cell Foam?

Posted on October 29, 2009 by Martin Holladay in Green Building Blog

Everyone agrees that spray polyurethane foam does a great job at reducing air leakage. But which type of insulation makes the most sense: open-cell foam or closed-cell foam? presents two spray-foam experts — Jim Coler, the owner of Coler Natural Insulation in Ionia, New York, and Neal Ganser, a spray-foam consultant from Bozeman, Montana — who explain the advantages of the two main types of spray foam insulation.

Open-Cell Foam Beats Closed-Cell Foam

Posted on October 28, 2009 by Anonymous in Green Building Blog

By Jim Coler

When shopping for spray foam insulation, many builders and homeowners are uncertain whether to choose an open-cell product or a closed-cell product. In my opinion, the choice is clear: for above-grade residential applications, the best choice is usually open-cell foam. In most cases, open-cell foam will be more economical, more flexible, and more forgiving with moisture than closed-cell foam.

Closed-Cell Foam Beats Open-Cell Foam

Posted on October 28, 2009 by Anonymous in Green Building Blog

By Neal Ganser

Replacing long-obsolete insulation materials with closed-cell or open-cell spray polyurethane foam is a big step in the right direction for energy efficiency. Of the two types of foam, it is closed-cell foam that truly answers all of the building envelope’s requirements for long-term sustainability. Compared to open-cell spray foam, closed-cell foam has a higher R-value and is less vapor-permeable.

Renewable Energy Feed-In Tariffs

Posted on October 27, 2009 by Alex Wilson in Energy Solutions

Vermont made history last week, becoming the first state to offer “feed-in tariffs” for electricity generated from renewable energy sources.

Feed-in tariffs have been used since the early 1990s in Europe, most notably in Germany, to jump-start the photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. (solar electricity) industry. In a nutshell, they are government-mandated, long-term power purchase contracts for electricity generated by renewable energy systems at rates that are significantly higher than the market rate for wholesale power.

Elements of Successful Websites

Posted on October 27, 2009 by Dina Lima in Business Advisor

Your website is your online storefront. We live in an Internet-driven society. One of the huge benefits that we all love and enjoy is instant access to all sorts of information. According to the Domain Name Industry Brief by VeriSign, Inc., the Internet now has more than 183 million domain names (1Q 2009). This is a 12% increase compared to the same quarter a year earlier.

Passivhaus Crosses the Atlantic

Posted on October 23, 2009 by Martin Holladay in Musings of an Energy Nerd

Last weekend I attended the Fourth Annual North American Passive House Conference in Champaign-Urbana, Ill. The conference offered a great opportunity to learn more about the Passivhaus standard and to discuss low-energy buildings with an experienced group of architects, engineers, and builders.

Improving Water Heater Efficiency

Posted on October 21, 2009 by Alex Wilson in Energy Solutions

Last week I wrote about a high-tech solution for water heating--heat-pump water heaters that can cut costs by more than half compared to conventional electric water heating. This week, I’ll address the low-tech efficiency side of water heating.

How Deep Is Your Footprint?

Posted on October 19, 2009 by Ann Edminster in Green Building Blog

In my house we’ve been talking a lot lately about consumption—more specifically, about the relationship between consumption and our carbon footprint. In the green-building world, when we talk about a footprint, it’s usually related to building design.

Return-Air Problems

Posted on October 16, 2009 by Martin Holladay in Musings of an Energy Nerd

In homes with a single central return-air grille, return air often struggles to find its way back to the furnace. The result: room-to-room pressure imbalances that lead to uneven room temperatures, comfort complaints, higher energy costs, and even moisture problems in walls and ceilings.

Pro/Con: Does Passivhaus Make Sense Over Here?

Posted on October 14, 2009 by Martin Holladay in Green Building Blog

John Straube, a prominent building science professor and a principal of the Building Science Corporation in Westford, Mass., asserts that applying the German PassivhausA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. standard to North American houses often results in expensive details that yield few energy-saving benefits.

In response, two prominent energy consultants, Marc Rosenbaum of Energysmiths and David White of Right Environments, challenge some of Straube's conclusions and defend the goals and methods of the Passivhaus standard.

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