The most recent blogs at Green Building Advisor

Slow Progress on New Blowing Agents for Polyiso

Posted on January 20, 2017 by Martin Holladay, GBA Advisor 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 75ºF 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 25ºF.

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, GBA Advisor 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?

What’s Wrong With Our New Furnace?

Posted on January 16, 2017 by Scott Gibson in Q&A Spotlight

John Melichar has upgraded the furnace in his two-level San Francisco home, one of several improvements that should have made the house more comfortable as well as more energy-efficient. The new furnace has the capacity recommended by his heating contractor, but so far the house seems less comfortable, not more comfortable.

In a post at GBA's Q&A forum, Melichar explains his concerns:

"Our contractor told us to buy a 60K BtuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. /h furnace; we opted for 96% AFUEAnnual Fuel Utilization Efficiency. Widely-used measure of the fuel efficiency of a heating system that accounts for start-up, cool-down, and other operating losses that occur during real-life operation. AFUE is always lower than combustion efficiency. Furnaces sold in the United States must have a minimum AFUE of 78%. High ratings indicate more efficient equipment. with two-stage variable blower — the Goodman GMVC960603BN.

Building Science Information for Builders

Posted on January 13, 2017 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Jacob Deva Racusin, a Vermont builder and educator, has just written a book called Essential Building Science. The book aims to provide builders — especially so-called “natural builders” — with a basic understanding of the ways that heat and moisture flows affect residential buildings. (The book is available from New Society Publishers for $34.95.)

New Energy-Saving Standards from Barack Obama

Posted on January 12, 2017 by Andrew deLaski in Guest Blogs

On December 28, 2016, the Department of Energy (DOEUnited States Department of Energy.) issued five new efficiency standards, culminating a decade of energy efficiency progress that began under President George W. Bush. The new standards, the last of many developed during the Obama administration, will save consumers money, help meet the nation’s energy needs, and reduce environmentally harmful emissions, including greenhouse gases.

Ontario Imposes Tougher Ventilation Requirements

Posted on January 11, 2017 by Greg Labbe in Guest Blogs

Ontario, Canada's most populous province, will increase the energy performance of homes by 15% starting in 2017. The changes are required under the province's updated building code known as SB-12. The two biggest changes are complementary: All new homes must have heat-recovery on their ventilation systems while incentives will be put in place for making buildings more airtight as verified by air leakage testing.

Accounting for Renewable Electricity Savings

Posted on January 10, 2017 by Anonymous in Guest Blogs

By ROBIN ROY

How much does it matter if energy efficiency programs like Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. or appliance energy standards save electricity generated by renewable resources like wind and solar, rather than from fossil fuel power plants? Certainly from the perspective of reducing carbon pollution, there’s a strong case that saving renewable electricity is not as valuable as saving energy generated from burning fossil fuels.

As the role of renewable electricity in the nation’s electricity supply grows, this question will become increasingly important to think through.

Toronto Passive: Designing a High-Performance Home

Posted on January 9, 2017 by Lyndon Than in Guest Blogs

Editor's Note: Lyndon Than is a professional engineer and 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. Consultant who took a year off from work to design and build a home with his wife Phi in North York, a district of Toronto, Ontario. This is the first in a series of posts about the project, beginning with the start of construction in early 2012. Than describes the process in his blog, Passive House Toronto.

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