The most recent blogs at Green Building Advisor

Is the Passivhaus Program Truly Innovative?

Posted on September 25, 2013 by Allison A. Bailes III, PhD in Building Science

Last month, Joe Lstiburek gave the fifth annual Twitterview from his crawl space. (Peter Troast of Energy Circle has published the transcript of this year’s event.) One of the pearls of wisdom dispensed by Joe was that, “Passivhaus is the only place where real innovation is happening.”

Ten Misconceptions About the Passive House Standard

Posted on September 24, 2013 by Monte Paulsen in Guest Blogs

I'm a small building energy modeler, and the tools of my trade are airtightness, insulation, window placement, and heat-recovery ventilation(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. . These are also the tools of the international 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. standard (known in Europe as the Passivhaus standard). And yet, almost every week, some veteran home builder patiently schools me as to why these building performance strategies — or Passive House requirements — are a waste of time or money.

I have compiled the most frequently cited arguments I hear; let's call them “Ten reasons not to build a Passive House.”

Upgrading a Shop’s Heating System

Posted on September 23, 2013 by Scott Gibson in Q&A Spotlight

Matt Cooper's 1,800-square-foot woodworking shop sits on a 6-inch concrete slab heated with a radiant-floor system. Unfortunately, the on-demand water heater that Cooper uses to heats the water for the in-slab tubing isn't performing well.

"I've been using a Takagi Jr. to heat it for the past couple of years but it's been no end of headaches," Cooper writes in a Q&A post at Green Building Advisor.

Air Sealing an Attic

Posted on September 20, 2013 by Martin Holladay in Musings of an Energy Nerd

If you want to improve the energy performance of an older house, one of the first steps is to plug your attic air leaks. Although many GBAGreenBuildingAdvisor.com articles address aspects of attic air sealing, no single article provides an overview of the topic. This article is an attempt to provide that missing overview.

I’ll try to explain how you can seal air leaks in a conventional vented, unconditioned attic. If your house has cathedral ceilings — that is, insulated sloped roof assemblies — the air sealing tips in this article don’t apply to your house.

Energy-Saving Features of the Serenbe Community

Posted on September 19, 2013 by Alex Wilson in Energy Solutions

In this blog last week I described some of the unique features of Serenbe, a New Urbanist community outside Atlanta, where I had the good fortune to be invited by the Bosch Experience Center as a speaker. I spent the better part of a day exploring the community.

This week I’ll describe some of the energy features at the 1,000-acre development.

Spray Foam Insulation Does Not Work with All HVAC Systems

Posted on September 18, 2013 by Allison A. Bailes III, PhD in Building Science

Earlier this year I got a question about a home that had spray foam insulation in the attic. There's nothing unusual about that. A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits.

But then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.

Spray Foam in Cold Climates

Posted on September 17, 2013 by Erik North in Guest Blogs

Spray foam is a great tool for insulating and weatherizing. It can be applied to horizontal and vertical surfaces. Once it is cured, it can be the air barrier and vapor and thermal control layers (at least closed-cell foam can), and it provides some of the highest R-values per inch available. It slices! It dices! It makes great sushi!

Why Weatherization Isn’t Enough

Posted on September 16, 2013 by Rachel White in Guest Blogs

Ask almost any building performance expert what you should do first to cut your utility bills and improve the energy efficiency of your home, and the answer will inevitably be to weatherize. And that’s as it should be. Most of our homes are rife with air leaks. According to the U.S. Department of Energy, in the average American home, 30 cents of every dollar spent on heating and cooling is lost to air leaks and insufficient insulation.

All About Wood Stoves

Posted on September 13, 2013 by Martin Holladay in Musings of an Energy Nerd

If you’ve been heating your house with wood for years, you probably don’t need to read this article. By now, you know all about the disadvantages and inconveniences that accompany wood heat, and yet you still heat with wood — either because you genuinely love wood heat, or because you love the low cost of the fuel. If you haven’t burned down your house by now, you may even have figured out how to install and operate your stove safely.

This article is addressed to a different audience: those who are thinking about buying their first wood stove.

Serenbe: a Green Town in the Making

Posted on September 12, 2013 by Alex Wilson in Energy Solutions

I’m just back from Atlanta, where I spoke on Saturday at the new Bosch Experience Center located in the unique Serenbe Community thirty miles southwest of Atlanta.

I gotta say, I was impressed!

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