The most recent blogs at Green Building Advisor

Can We Live Happily Underground?

Posted on January 30, 2017 by Scott Gibson in Q&A Spotlight

Earth-bermed houses built with the Passive Annual Heat Storage (PAHS) approach are a little off the beaten track for most builders and prospective homeowners. These houses go back a bit: John N. Hait described the construction of an early "umbrella house" in the 1980s.

As unusual as they may be, PAHS houses have their advocates. One of them is Laurel Davison, who is planning to build one in Missouri on a gently sloped lot with an unimpeded southern exposure.

In Search of a DIY Guide to Rooftop PV

Posted on January 27, 2017 by Martin Holladay in Musings of an Energy Nerd

Most new grid-tied 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. (PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.) systems are installed by solar contractors. Here’s what usually happens: the homeowners call up a few local solar companies; representatives come to the house to make a site assessment; the homeowners choose the contractor whose quote sounds reasonable and sign a contract for the work. The homeowners don’t even have to put up a ladder; all they have to do is sign a check.

Measuring (and Understanding) Humidity

Posted on January 26, 2017 by Peter Yost in Building Science

Author’s Note: I can’t even start this blog before thanking Lew Harriman of Mason-Grant Consulting. Lew very patiently and gently hammered me into a much better understanding of humidity in air and its measurement. While any errors or lack of clarity regarding humidity and its measurement are mine, much of the insight and many of the resources mentioned here are Lew’s.

City of Aspen Dumps Energy Rating Index

Posted on January 25, 2017 by Allison A. Bailes III, PhD in Building Science

The city of Aspen, Colorado has bucked the trend. Well, actually two trends, but first things first.

New York Proposes New Rates for Distributed Energy

Posted on January 24, 2017 by Anonymous in Guest Blogs

By MILES FARMER and MARK LEBEL

How to Make Hydropower More Environmentally Friendly

Posted on January 23, 2017 by Anonymous in Guest Blogs

By MATT WEISER

Humanity got its first large-scale electricity thanks to hydropower. On August 26, 1895, water flowing over Niagara Falls was diverted to spin two generators, producing electricity to manufacture aluminum and carborundum. Since then, millions of dams have been built worldwide, transforming the energy of moving water into the energy of moving electrons. When we need it, the water spins magnets past a coil of copper wire to give us heat, light, and entertainment.

Slow Progress on New Blowing Agents for Polyiso

Posted on January 20, 2017 by Martin Holladay in Musings of an Energy Nerd

R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. tests by the National Roofing Contractors Association and the Building Science Corporation have revealed that the thermal performance of polyisocyanurate is greatly reduced at cold temperatures. While the R-value of polyiso at a mean temperature of 75°F might be about R-5.7 per inch, the effective R-value of the polyiso drops to about R-4.8 per inch at a mean temperature of 25°F.

Wolfe Island Passive: Ready for Roofing

Posted on January 19, 2017 by David Murakami Wood in Guest Blogs

Editor's note: David and Kayo Murakami Wood are building what they hope will be Ontario's first certified Passive HouseA 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. on Wolfe Island, the largest of the Thousand Islands on the St. Lawrence River. They are documenting their work at their blog, Wolfe Island Passive House. For a list of earlier posts in this series, see the sidebar below.

Designing Duct System Vents for Good Air Flow

Posted on January 18, 2017 by Allison A. Bailes III, PhD in Building Science

You're at a cocktail party when, as it so often does, the discussion turns to HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. design. What do people talk about? Load calculations. Manual J. Oversizing. Maybe a little about duct sizing or location. But how many times have you been in that conversation and heard someone talk about what happens at the end of the ducts? Yes, I'm talking about the often overlooked part of HVAC design in which the designer selects the proper terminations for the duct runs.

Getting to Zero Carbon in Menlo Park

Posted on January 17, 2017 by Anonymous in Green Building Blog

By DIANE BAILEY

What happens when a small Silicon Valley city flanked by Stanford University and Facebook headquarters sets its sights on a climate-neutral future? A zero carbon pathway and a fresh approach to the built environment emerge. But how?

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