The most recent blogs at Green Building Advisor

Why New U.S. Ozone Standards Aren’t Enough

Posted on October 29, 2015 by Noelle Eckley Selin in Guest Blogs

On October 1, the U.S. Environmental Protection Agency announced new standards for ground-level ozone. Much of the discussion around the new regulations has centered either on whether they are protective enough of health or on how much implementation will cost.

The U.S. is not the only country taking action to restrict ground-level ozone – and from a health perspective, even the new, lower U.S. limit is still higher than guideline levels in other countries.

Solving a Crawl Space Water Mystery

Posted on October 28, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

When I started Energy Vanguard in 2008, I didn't know how the company would evolve and had thought early on that I may get back into home performance contracting. I did a couple of jobs, the last one being a crawl space encapsulation for my friends Tony and Gabriella. They had a house over a moldy crawl space, and Gabriella had developed a cough since moving in.

Tearing Down to Start Again

Posted on October 27, 2015 by Michael Trolle in Guest Blogs

Editor's note: This is the second installment in a series of blogs by Michael Trolle about the construction of his Passivhaus home in Danbury, Connecticut. The first part was published as “Building My Own Passive House.”

The Best Way to Insulate a Foundation

Posted on October 26, 2015 by Scott Gibson in Q&A Spotlight

Nethaniel Ealy, a builder in Idaho who's about to pour a concrete basement foundation, is trying to come up with insulation and waterproofing details that will be effective and within the budget.

The current plan is to place 2 inches of extruded polystyrene (XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation.) on the outside of the foundation walls. At some point in the future, the homeowners would place another 2 inches of foam on the inside of the foundation walls between 2x2 studs, and then apply drywall over the studs.

Rethinking Durability

Posted on October 23, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Does durability matter? Most green building advocates seem to think that green builders should always aim to build durable structures. My own opinion differs; in fact, as I explained in a 2009 article on the topic, it’s hard to see any correlation between durability and “greenness.”

I recently had an opportunity to reconsider the advantages and disadvantages of durability when my wife and I visited the Pont du Gard in Languedoc-Roussillon, France.

Beyond Sprawl: The Solar Suburbs of the Future

Posted on October 22, 2015 by Marc Gunther in Guest Blogs

Imagine a truly green suburb, one in which energy-efficient homes are powered by rooftop solar panels and electric cars glide quietly down the streets. Businesses, energy experts, and scholars say low-carbon suburban living is not only possible, but on its way, though not in the short run. Some glimpses of the future:

Winterizing Tips That Work

Posted on October 21, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Of course, everyone knows that caulking your windows and weatherstripping your doors won't help you much. Right?

Well, all the cool kids do anyway, and that includes you because you're here reading this article. A lot of the standard advice on getting your home ready for winter is filled with bunk. That includes the stuff that comes from many utility companies and famous people who try to help you save money, like Clark Howard. But what should you really do to prepare your home for an efficient and cozy winter?

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.

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