Energy Vanguard Blog

A Net Zero Energy Home in a Beautiful Green Community

Posted by Allison Bailes on Tue, Nov 26, 2013

I spoke at Serenbe, a beautiful green community southwest of Atlanta, this weekend and got a chance to visit a net zero energy home while there. Built by Luis Imery, one of the home energy raters we're a HERS provider for, the home has garnered quite a bit of recognition. In fact, they recently picked up a pretty big award from Southface.

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Tags: ENERGY STAR, HVAC, building enclosure, heating & cooling distribution, insulation, air leakage, energy code, comfort, spray foam, indoor air quality, solar energy, ventilation

Is Energy Efficiency More Important Than Indoor Air Quality?

Posted by Allison Bailes on Thu, Nov 21, 2013

I was searching the Interwebs for data on what percentage of buildings are designed by architects this week when I came across the Home Design Trends Survey from the American Institute of Architects (AIA). (If you can point me toward some good sources for my original question, please do.) The survey included several types of questions and charts, but the one that really caught my eye was (nominally) about the popularity of products. The chart below shows the results. (Click to see all the charts in larger sizes.)

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Tags: HVAC, building enclosure, air leakage, indoor air quality, ventilation

Fixing an Old House? Follow Einstein's Advice

Posted by Allison Bailes on Mon, Nov 4, 2013

I get a lot of questions from people asking how they should go about fixing their homes. Sometimes it's specific (What's the best way to insulate my kneewalls?), and sometimes it's a hands up in the air, With all these problems, where do I start?  I'll focus on the latter today and let Albert Einstein provide the guidance you need.

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Tags: HVAC, building enclosure, crawl space, air leakage, attic, comfort, windows, indoor air quality, diagnostic/performance testing, solar energy, water heating, health & safety, ventilation

Is the ENERGY STAR New Homes Program Dying?

Posted by Allison Bailes on Wed, Oct 30, 2013

Back in 2009, I attended a webinar given by Sam Rashkin, head of the ENERGY STAR new homes program at the time. (He has since left the EPA for the DOE.) He explained the changes coming in the program as they prepared for the transition from what we now call Version 2 to the new Version 3. The part of the webinar that got the most attention was the change from a fixed HERS Index to a variable HERS Index target, but he also made a prediction.

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Tags: RESNET/BPI, ENERGY STAR, HVAC

What Happens in the Real World Stays in the Real World

Posted by Allison Bailes on Fri, Oct 11, 2013

Today for your enjoyment, I have some mighty fine photos for you. They speak for themselves, really, so I don't have to say much. First up is a nice package unit air conditioner (or heat pump) in Little Rock, Arkansas. The flex duct—yes, flex—runs from the ground up to the attic. Notice that it's got its own notch cut into the soffit, too, although I suspect that might have been there before someone changed out the duct.

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Tags: HVAC, heating & cooling distribution

This Little Ventilation Mistake Can Lead to Comfort Problems

Posted by Allison Bailes on Wed, Oct 9, 2013

If you're designing a ventilation system, first you have to determine how much air the house needs. You can use ASHRAE 62.2 or the new BSC-01 for that task. Then you have to decide what type of ventilation system to use: positive pressure, negative pressure, or balanced. In many green homes, the balanced system is becoming a popular choice. I've seen some installations lately, though, that are missing a key component.

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Tags: HVAC, design, heating & cooling distribution, comfort, ventilation

Why Do So Many Expensive Homes Get Walmart-Class HVAC Systems?

Posted by Allison Bailes on Tue, Oct 8, 2013

The fellow standing in the home he's having built is proud. It's his dream home in Brookline, Massachusetts after all. The Wall Street Journal last week published an article about affluent home buyers getting their own jumbo construction loans to do just as Mr. Deshpande has done. Usually, they hire a home builder to build the home, but if you look at that photo, you'll see a mistake that's common even in million dollar homes.

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Tags: HVAC, design, heating & cooling distribution, comfort, spray foam

Confessions of a Building Science Zealot

Posted by Allison Bailes on Mon, Sep 30, 2013

Hi. My name is Allison, and I'm a building science zealot. I preach the gospel of building science, yet in my own life, I fall short of the perfection I exhort others to attain. Yes, I once built a green home that had many of the features I promote here, but if you've been reading this blog for a while, you know that my current residence is far from perfect. How so? Let me count the ways.

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Tags: HVAC, building enclosure, heating & cooling distribution, air leakage, windows, moisture problems, health & safety

Have You Seen What's in Your Hotel Room Air Conditioner?

Posted by Allison Bailes on Wed, Sep 25, 2013

You just never know what you'll find in a hotel room. I'm a curious guy so I have to check things out, and this week I found some interesting stuff in the air conditioner of the room they gave me here in Hattiesburg. As I was sitting at the desk, I noticed that the fan looked white as the squirrel cage blades spun around. So I popped the cover off and here's what I saw.

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Tags: HVAC, indoor air quality

What Is the Best Way to Deal with Crawl Space Air?

Posted by Allison Bailes on Mon, Sep 16, 2013

If you have a home with a crawl space—or are building or buying one—you have several options on what to do with that particular foundation type. Most crawl spaces are vented to the outdoors, but over the past decade, encapsulating the crawl space (as shown below) has gained favor among builders of green and energy efficient homes. It's often seen as the best way to eliminate the moisture problems that often result from vented crawl spaces. But what do you do about the air down there?

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Tags: HVAC, insulation, crawl space, air leakage, moisture problems, ventilation