The most recent blogs at Green Building Advisor

Solar Decathlon 2011: A Flat-Roofed House from Florida International

Posted on March 15, 2011 by Richard Defendorf in 2011 Solar Decathlon

In terms of climate, there isn’t much difference between living in South Florida and some of the more inviting parts of the Caribbean just to the south, where the rhythms of warm, sunny, often humid summer days seem to stretch on indefinitely, and where summer-afternoon thunderstorms, an assortment of aggressive insects, and seasonal hurricanes break up the quiet.

Are High-Performance Windows Worth Their High Cost?

Posted on March 14, 2011 by Scott Gibson in Q&A Spotlight

Randy George is in the final planning stages for a new house he will be building this summer in Vermont, and from the sound of it he won't have much trouble staying warm through those long winters.

In addition to R-45 walls, an R-65 roof and R-20 slab, the house will have air infiltration rates lower than one air change per hour at 50 pascals of depressurizationSituation that occurs within a house when the indoor air pressure is lower than that outdoors. Exhaust fans, including bath and kitchen fans, or a clothes dryer can cause depressurization, and it may in turn cause back drafting as well as increased levels of radon within the home.. Although not quite meeting the 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, that's extremely tight construction.

Natural Gas — Not as Green as it Used to Be

Posted on March 11, 2011 by Alex Wilson in Energy Solutions

Natural gas has been in the news a lot recently.

On the economics side, we are seeing a fascinating divergence of petroleum and natural gas prices. For decades, oil and gas prices have tracked pretty closely — natural gas prices rising and falling as international political events boosted or depressed oil prices. Today, for the first time, as oil prices are surging, natural gas prices are still falling. In the last few weeks, natural gas prices have fallen to historic lows, compared with oil.

How to Install Cellulose Insulation

Posted on March 11, 2011 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

In some parts of the U.S. — notably northern New England — cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection. has been widely used for more than 30 years. In other parts of the U.S., however, cellulose insulation is just beginning to gain traction.

Of course, cellulose insulation is installed with different techniques than those used to install fiberglass batts or spray foam. To help explain these techniques to builders who are unfamiliar with cellulose, we decided to interview Bill Hulstrunk, the technical manager at National Fiber, a manufacturer of cellulose insulation in Belchertown, Massachusetts.

Recycling Vinyl Siding

Posted on March 10, 2011 by Peter Yost in Green Communities

In 1998, while at the NAHBNational Association of Home Builders, which awards a Model Green Home Certification. Reseach Center, I worked on a vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate). siding recycling project in Grand Rapids, MI. It was pretty simple: siding installers stuffed their cut-off waste into the long cardboard boxes the new siding came in, and back-hauled both to the same place they bought their vinyl siding stock. There, the vinyl cut-offs were placed in one container and the cardboard in another. The vinyl cut-offs were baled and when a 40,000-pound load was accumulated, a plastics broker would negotiate a price for the tractor-trailer load.

Recycling vinyl siding

How to Sell Green Upgrades: Energy Audits

Posted on March 9, 2011 by Michael Strong, LEED Associate, CGP in Business Advisor

Before I move onto the topic du jour, How to Sell Energy Audits, I want to remind my readers of the context of this series. Remember, when I talk of selling various green options, they are always sold in the context of the house we are building or remodeling.

Solar Decathlon 2011: New Zealand Vacation Cabins Inspire Designers

Posted on March 8, 2011 by Richard Defendorf in 2011 Solar Decathlon

For many New Zealanders, forging a close connection between one’s home and its environment is more than an afterthought. While that is partly because the island nation is such a beautiful place, it's also because the New Zealand climate is generally mild and sunny.

LEED for Homes Online Scoring Tool Needs a Lot More Work

Posted on March 7, 2011 by Carl Seville, GBA Advisor in Green Building Curmudgeon

The USGBC just released its online scoring tool for LEED for Homes, a much-anticipated advance in the program. After months of announcements and requests for people to sign up, the tool was finally available to the public on February 28th. I took some time to run through it, and I can report there are things to like about it, but it needs a lot more work to be truly useful.

How to Calculate the Value of Energy Improvements

Posted on March 7, 2011 by Scott Gibson in Q&A Spotlight

Adding more insulation, replacing an inefficient furnace, or performing air-sealing measures are oft-recommended strategies for lowering energy consumption and saving money.

Aaron Vander Meulen puts his finger on a key issue, however, when he wonders whether there is a way of determining exactly how much money improvements such as these will save.

Location Efficiency

Posted on March 4, 2011 by Alex Wilson in Energy Solutions

We spend a lot of time and money making our homes more energy efficient. Whether adding insulation, upgrading windows, replacing incandescent light bulbs, or replacing appliances, our efforts to use less energy save us money and help the environment. But what about where we live?

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