The most recent blogs at Green Building Advisor

Should We Promote Heat Pumps to Save Energy?

Posted on June 2, 2016 by Steven Nadel in Guest Blogs

Heat pumps are going through a period of innovation. Ductless heat pumps are more available; cold climate heat pumps have been developed; higher minimum efficiency standards for heat pumps have been established by the U.S. government; and gas-fired heat pumps have been developed.

Air Flow Pathways in a Leaky Exterior Wall

Posted on June 1, 2016 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

This spring I spent a lot of hours in my bathroom. I was sick. Really. I was sick and tired of having an outdated bathroom that was falling apart. So when my wife hit the road one Monday in late April to drive across the country, I got out my wrecking bar. The lead photo shows what it looked like at the end of my first full day of demolition.

I opened up the plumbing wall first. Lots of fun stuff, there. But the real fun came when I opened up the exterior wall. The four termite-damaged studs were part of that fun, but something else was even better.

The True Cost of Electricity

Posted on May 31, 2016 by Ferit Ucar in Guest Blogs

This is the second of a four-part series that takes a deep dive into the economics of our electric system and the role pricing can play in accelerating the clean energy economy. The first article in the series was Transforming the Electric System.

Blue Heron EcoHaus: Placing the Concrete Floors

Posted on May 30, 2016 by Kent Earle in Guest Blogs

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 Adding Walls and Roof. 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.)

How Much Insulation is Too Much?

Posted on May 27, 2016 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

In a presentation at this year’s BuildingEnergy 16 conference in Boston, three energy experts joined forces to tackle a common question: “How much insulation is enough and how much is too much?”

The presentation had an opaque title and subtitle: “How We Sleep at Night: Energy Metrics and Decision Making in Residential Design.” Although presenters' intended meaning may have been obscure, they were trying to answer two questions: At what point are envelope improvements a waste of money? And what metrics or rules of thumb should we use to determine when enough is enough?

Getting More Energy from the Sun

Posted on May 26, 2016 by Tara Dhakal in Guest Blogs

Global demand for energy is increasing by the hour as developing countries move toward industrialization. Experts estimate that by the year 2050, worldwide demand for electricity may reach 30 terawatts (TW). For perspective, one terawatt is roughly equal to the power of 1.3 billion horses.

Energy from the sun is limitless – the sun provides us 120,000 TW of power at any given instant – and it is free. But today solar energy provides only about 1% of the world’s electricity. The critical challenge is making it less expensive to convert photo-energy into usable electrical energy.

Transforming the Electric System

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

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 in Guest Blogs

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.

Installing a Concrete Slab the Right Way

Posted on May 23, 2016 by Scott Gibson in Q&A Spotlight

As part of a remodel of his San Francisco area home, Torsten Budesheim is converting the 700-square-foot lower level into living space. An existing slab has been removed, and Budesheim has removed a few inches of material to increase the finished ceiling height. Now, he's nearly read to place a new 5-inch-thick slab that will include tubing for radiant heat.

How to Order Windows

Posted on May 20, 2016 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Anyone who needs to choose windows for a new home has a lot of decisions to make. In this article, I’ll try to provide an overview of some of the factors to keep in mind when ordering windows.

Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!