Guest Blogs

Transforming the Electric System

Posted on May 25, 2016 by Beia Spiller and Kristina Mohlin

Electricity markets around the world are transforming from a model where electricity flows one way (from electricity-generating power plants to the customer) to one where customers actively participate as providers of electric services. But to speed this transformation and maximize its environmental and cost benefits, we need to understand how customer actions affect the three distinct parts of our electric system: generation, transmission, and distribution.

Sizing a Modulating Condensing Boiler

Posted on May 24, 2016 by Dana Dorsett

For the past few decades, an increasingly popular space heating option is a system with a modulating condensing (mod-con) boiler. Because these boilers can potentially have a high efficiency (90-95% or higher), they are often promoted by state and utility subsidy programs.

In a well-designed system, the boiler’s efficiency can hit or even exceed its nameplate 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. . But as installed, most fall well short of their AFUE test numbers and often suffer an abbreviated lifespan. Efficiency problems and lifespan-crippling sizing errors could be avoided with a modest amount of analysis.

Should You Worry About PFOA in Your Water?

Posted on May 19, 2016 by Veronica Vieira

Over the past few months, several communities in upstate New York and New England have detected PFOA — perfluorooctanoic acid, or C8, a chemical linked to a range of health issues from cancer to thyroid disease — in their drinking water.

PFOA is a fluorinated compound that is absorbed into our bodies through inhalation or ingestion. The chemical can then accumulate in our blood serum, kidneys, and liver.

A Pretty Good Retrofit in Montana

Posted on May 17, 2016 by Jim Baerg

This is a story of a wonderful, tempestuous relationship. For me, it began nine years ago as an unplanned series of events: a chance encounter between a wandering idealist and small town girl. The happenstance meeting quickly progressed to an impulsive, long-term proposal. Soon thereafter, the commitment was formalized by the exchange of legal documents through the mail.

Blue Heron EcoHaus: Adding Walls and Roof

Posted on May 16, 2016 by Kent Earle

Editor's note: Kent Earle and his wife, Darcie, write a blog called Blue Heron EcoHaus, documenting their journey “from urbanites to ruralites” and the construction of a superinsulated house on the Canadian prairies. Their previous blog on GBAGreenBuildingAdvisor.com was called Dealing With Really Bad Water. The blog below was originally published in July 2015. (A complete list of Kent Earle's GBA blogs is provided in the “Related articles” sidebar below.)

Testing Air Leakage in Multifamily Buildings

Posted on May 12, 2016 by Sean Maxwell

In a previous article, I explained why it's important to prevent air leaks between individual apartments in multifamily buildings — a type of air sealing known as "compartmentalization." With my compartmentalization rant over, let me tell you how we can change our building codes to find a solution to the problem of leaky apartments, and why you should support a change to the language of the International Energy Conservation Code.

The World Needs Sustainable Forestry

Posted on May 11, 2016 by Joshua Axelrod

The Forest Stewardship Council (FSCForest Stewardship Council. An independent, nonprofit organization that promotes responsible forest management through the use of a third-party certification process. FSC certification includes a chain-of-custody requirement that tracks sustainability of wood products from growth to end use.), the world’s leading independent certifier of sustainably managed forests, is facing increasingly vitriolic attacks from various industry trade groups and players in Canada, who argue that the FSC’s policies — specifically their move toward requiring protection of threatened intact forest landscapes — will cause them to lose access to significant wood volumes they need to maintain their current operations.

CarMic House: No, We Are Not Crazy

Posted on May 10, 2016 by Carri Beer and Michael Hindle

Editor's note: Carri Beer and Michael Hindle are renovating this 1954 house in Catonsville, Maryland. Hindle is a 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 and owner of Passive to Positive. Beer is a registered architect who has been practicing sustainable architecture for 18 years. She is an associate principal with Brennan+Company Architects. The couple's first post about the project, Rebuilding a Mid-Century Dinosaur, was published on March 2.

The LEED Pilot for Wood

Posted on May 5, 2016 by Stuart Kaplow

The U.S. Green Building Council is to be applauded for the release last week of the new pilot credit, MRpc102 – Legal Wood.

There may be no single subject matter more discussed with over the 15-year history of 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. than forest product certification. And that this new pilot credit continues the discussion is positive.

But make no mistake: this new alternative compliance path credit does not alter the existing LEED credit, NC v4 MRc3, that mandates: "Wood products must be certified by the Forest Stewardship Council(FSC) Nonprofit organization that promotes forestry practices that are sustainable from environmental and social standpoints; FSC certification on a wood product is an indicator that the wood came from a well-managed forest. or USGBCUnited States Green Building Council (USGBC). Organization devoted to promoting and certifying green buildings. USGBC created the LEED rating systems.-approved equivalent."

When Will Rooftop Solar Be Cheaper Than the Grid?

Posted on May 3, 2016 by Joshua Rhodes

The National Renewable Energy Laboratory said recently that rooftop solar panels have the potential to generate nearly 40% of electricity in the U.S. But what about the cost of going solar?

Many people ask when the cost of producing power from 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.) panels will be equal to or less than buying from the grid — a point called “grid parity.” Reaching grid parity could accelerate solar adoption.

But in asking the question, they often compare apples to oranges and forget that the answer varies from place to place and from one type of installation to another.

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