Energy Vanguard Blog

Joe Lstiburek's Ideal Double-Stud Wall Design

Posted by Allison Bailes on Wed, Apr 29, 2015

Joe Lstiburek called me last week to set the record straight. I had written an article about a study of moisture in double-stud walls in a Massachusetts home, and his company, Building Science Corporation (BSC), had done the research as part of the Building America program. They found elevated moisture content in the cold, exterior sheathing, and Joe wanted to make sure everyone knew, "I would never build that wall because I consider it too risky."

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Tags: insulation, moisture problems

Is This the End of the Double-Wall, Cold Sheathing Scare?

Posted by Allison Bailes on Wed, Apr 22, 2015

Insulation is good. More insulation is better (although at some point, more may not be cost effective). It reduces the amount of heat a home loses in winter or gains in summer. You can get there by building thicker walls and putting more insulation in the cavities, or you can put insulation on the outside of the structure, as in the Perfect Wall. The photo below shows thick insulation in the cavities of a home with double-wall construction.

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Tags: insulation, air leakage, moisture problems, ventilation

An Interview with Terry Brennan — a Building Science Pioneer

Posted by Allison Bailes on Wed, Apr 15, 2015

Last week I got a chance to sit down and talk with Terry Brennan in Dallas at the Air Barrier Association of America’s annual conference. He may not be as famous as Joe Lstiburek, but he’s every bit the building science pioneer. Armed with a physics degree, the ASHRAE Handbook of Fundamentals, and a desire to reduce the environmental impact of buildings, he built houses and wrote energy modeling computer programs back in the 1970s and ‘80s. When he finally met Lstiburek in the early ‘80s, he learned not to bet against Joe’s ability to do ridiculous things. Read the transcript of our conversation and find out what that bet was and more.

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Tags: conferences, insulation, air leakage, environment & sustainability

California Mistakes Put Spray Foam Insulation on the "Bad List"

Posted by Allison Bailes on Tue, Mar 31, 2015

Last summer I learned about the state of California's efforts to create more healthful buildings and working conditions. In 2008, they passed the California Green Chemistry Initiative with the intent of reducing state residents' exposure to toxic chemicals. California leads the US in new directions all the time, and green chemistry could be another. Unfortunately, though, they were slow out of the gate and their initial attempts to implement the law don't instill confidence.

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Tags: insulation, spray foam, environment & sustainability, health & safety

Insolation Is Not a Typo for Insulation

Posted by Allison Bailes on Fri, Mar 27, 2015

In 1993 I took a graduate course in solar energy from Professor Yogi Goswami. It was a great course, and one of the projects we had to do was to compile a whole binder full of solar radiation data for Gainesville, Florida. I used an ancient spreadsheet called Lotus 1-2-3 (remember that?) to do all the calculations for various azimuth and elevation angles throughout the year. Another thing I learned in the class was a new word.

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Tags: insulation, solar energy

A Beautiful Solar Home in Utah Nears Net Zero Energy Use

Posted by Allison Bailes on Wed, Mar 18, 2015

I'm writing this on St. Patrick's Day so let me tell you a wee bit about the O'Mearas. Kevin and Svetlana O'Meara live in a beautiful home in Utah that's oh-so-close to being a net zero energy home. After I wrote about how home building is like skiing two years ago, Kevin invited me out to see their home and this year I managed to do so. My wife and I visited them for two days last week and Kevin told me all about the house, including his one major regret.

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Tags: ENERGY STAR, design, heating & cooling distribution, insulation, air leakage, energy code, energy conservation, comfort, windows, environment & sustainability, solar energy, water heating, ventilation, heating & cooling, green building

The Layers and Pathways of Heat Flow in Buildings

Posted by Allison Bailes on Tue, Feb 24, 2015

We used to build houses without giving much thought to heat flow through the walls, ceilings, and floors. The main thing was to provide some resistance against wind and rain, and then we'd get a fire going to try to make the indoor temperatures bearable. If you've ever lived in an old, uninsulated house, you know that method didn't work that well so later we started putting insulation into the cavities in building assemblies. Homes with insulated cavities are much more comfortable, but how exactly does heat flow through building assemblies? Turns out there are two ways.

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Tags: insulation, heating & cooling

The One Thing I'd Love to See Building Enclosure Workers Do

Posted by Allison Bailes on Tue, Jan 20, 2015

I think a lot about building enclosures. I've looked at a whole lot of houses and seen a whole lot of problems with the enclosure. I've also seen a few good ones, although they're all too rare. If you've been reading this blog for a while, you know I've also written about this topic a lot and have posted a lot of photos, of both the bad and the good. Today I'm going to tell you the one thing I'd love to see when I look at building enclosures.

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Tags: building enclosure, insulation, air leakage

Fiberglass Insulation Manufacturer Gets Serious About Installation

Posted by Allison Bailes on Fri, Jan 16, 2015

One of the major fiberglass insulation manufacturers (the color in the photo below gives away which one I'm talking about) is getting serious about the installation quality of fiberglass batt insulation. They've put out a video (embedded below) and a document showing how to achieve RESNET Grade 1 installation quality with fiberglass batts. Have you seen these things yet?

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Tags: RESNET/BPI, insulation

The Fundamentals of Heating and Cooling Degree Days, Part 1

Posted by Allison Bailes on Wed, Nov 12, 2014

Let's say you did some work on your home to make it more energy efficient - air sealing, more attic insulation, and a duct system retrofit. You've got your energy bills for 12 months before and 12 months after you did the work, and now you want to see how much energy you saved. So you sit down with all 24 months worth of utility bills, convert everything to a common unit if you use more than one type of fuel, and take a look at the numbers. Unless, however, you take into account another important factor, you may be led to incorrect conclusions.

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Tags: insulation, air leakage, heating & cooling