The most recent blogs at Green Building Advisor

Utilities Should Stop Driving With the Brakes On

Posted on October 20, 2015 by Philip Henderson in Guest Blogs

We've found that many electric utilities have contradictory policies in place. It's like driving with the brakes on.

Building My Own Passive House

Posted on October 19, 2015 by Michael Trolle in Guest Blogs

This is the first entry in what will be a series of columns about the design and construction of my own 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.. This is a rigorous process, and although the house is finished, certification (through the Passive House Institute U.S.) is not yet assured. I hope to provide an inside and personal look at the various economic, design, building, and decision-making processes involved. I also hope to give you a better understanding of some of the Passive House building practices.

Ductless Minisplits May Not Be As Efficient As We Thought

Posted on October 16, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

A recent monitoring study of ductless minisplits installed in seven New England homes found that these heating appliances had lower airflow rates and lower coefficients of performance (COPs) than expected. The average COP of these air-source heat pumps ranged from 1.1 at the house with the least-efficient minisplit to 2.3 at the house with the most-efficient minisplit.

The results of the study raise at least as many questions as they answer. Perhaps the most useful outcome of the study is that it sets up a framework for recommendations that could enhance minisplit efficiency.

High Performance Walls, Part 3

Posted on October 15, 2015 by Zack Semke in Guest Blogs

This is the third of four posts delving into the anatomy of high-performance wall assemblies, beginning with the Karuna House in Oregon. This week’s post explains our approach at the Glasswood 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. Retrofit.

What One Change Would You Make to LEED?

Posted on October 15, 2015 by Stuart Kaplow in Guest Blogs

I recently asked four score and seven people familiar with green building, “What one change would you make to LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. to encourage green building?”

How the Stack Effect Can Defeat Your Winterizing Efforts

Posted on October 14, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Caulk your windows. Weatherstrip your doors. It's that time of year again.

No, I don't mean the time of year when you should do those things. I mean it's the time of year when all the news stories that include this ineffective advice start appearing. There's a lot of bad advice included in those articles, but let's just look at why the caulking and weatherstripping advice will provide minimal relief.

Pouring the Slab and Framing the Walls

Posted on October 13, 2015 by Brian Post in Guest Blogs

Editor's note: This is the second in a series of blogs chronicling the design and construction of a house owned by Brian Post and Kyra Salancy. The first blog in the series was titled Building a Small House in the White Mountains.

Detailing Exterior Walls in Minnesota

Posted on October 12, 2015 by Scott Gibson in Q&A Spotlight

In Minnesota, Jeff Fredrickson is planning a new house, and his research has included lots of reading on the design and construction of exterior walls. His goals are twofold: a wall that will stay mold-free for decades, and one that is "somewhat energy efficient."

Starting at the inside, the wall would go like this: drywall, a polyethylene vapor barrier, JM Spider insulation in 2x6 stud walls, 1/2-inch plywood sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. , a water-resistive barrierSometimes also called the weather-resistive barrier, this layer of any wall assembly is the material interior to the wall cladding that forms a secondary drainage plane for liquid water that makes it past the cladding. This layer can be building paper, housewrap, or even a fluid-applied material. (Benjamin Obdyke HydroGap), fiber cement and stone veneer claddingMaterials used on the roof and walls to enclose a house, providing protection against weather. .

GBA Prime Sneak Peek: Reassessing Passive Solar Design Principles

Posted on October 9, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

GBAGreenBuildingAdvisor.com Prime subscribers have access to many articles that aren't accessible to non-subscribers, including Martin Holladay's weekly blog series, “Musings of an Energy Nerd.” To whet the appetite of non-subscribers, we occasionally offer non-subscribers access to a “GBA Prime Sneak Peek” article like this one.

Reassessing Passive Solar Design Principles

Posted on October 9, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Everybody loves passive solar design. Back in the 1970s, “passive solar” was the essential first step for cold-climate builders. It was considered an approach with obvious advantages over complicated “active solar” schemes that required pumps, fans, and electronic controls.

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