Building Science

Enterprise Green Communities and Passive House

Posted on October 7, 2015 by Allison A. Bailes III, PhD, GBA Advisor

The best green building program you've never heard of is probably Enterprise Green Communities. Everyone knows about 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. , of course. Regional programs, such as EarthCraft House and Minnesota GreenStar, also have name recognition in their areas. But unless you've been involved with Enterprise Green Communities, you may not have even heard of it. The recent release of their new program criteria means that it's time for that lack of name recognition to change.

The Department of Energy Chooses a Definition for Net Zero

Posted on September 30, 2015 by Allison A. Bailes III, PhD, GBA Advisor

A few weeks ago, I wrote about whether homes that produce as much energy as they use should be called net zero energy or zero net energy homes. Several readers offered up another choice: zero energy homes.

How to Become a Building Enclosure Control Freak

Posted on September 23, 2015 by Allison A. Bailes III, PhD, GBA Advisor

Frank Lloyd Wright was a control freak. This was a guy who not only designed houses but also all of the trim details and even the furniture.

The Science of Air Flow in Flex Duct

Posted on September 16, 2015 by Allison A. Bailes III, PhD, GBA Advisor

Sagging flex duct is bad for air flow. We all know it. We all talk about it. It turns out there's research data to prove it, too. Texas A&M did a study a few years ago to look at the pressure drop that occurs for different levels of compression. If you're not familiar with this study, the results may astound you.

A Few Pressure Testing Tips and Tricks

Posted on September 9, 2015 by Allison A. Bailes III, PhD, GBA Advisor

A typical BPI Building Analyst spends four to five days in a class learning how to do blower door testing, along with all the other stuff they need to know. HERSIndex or scoring system for energy efficiency established by the Residential Energy Services Network (RESNET) that compares a given home to a Home Energy Rating System (HERS) Reference Home based on the 2006 International Energy Conservation Code. A home matching the reference home has a HERS Index of 100. The lower a home’s HERS Index, the more energy efficient it is. A typical existing home has a HERS Index of 130; a net zero energy home has a HERS Index of 0. Older versions of the HERS index were based on a scale that was largely just the opposite in structure--a HERS rating of 100 represented a net zero energy home, while the reference home had a score of 80. There are issues that complicate converting old to new or new to old scores, but the basic formula is: New HERS index = (100 - Old HERS score) * 5. raters get all that, too, but also have to learn how to do duct leakage testing. Then there’s that whole big bunch of people who have gone through one or two day intensive blower door and duct leakage training for energy code compliance. When they’re done with the training, how do they figure out how to do pressure testing in the real world?

Ten Essential Steps to a Pretty Good House

Posted on September 2, 2015 by Allison A. Bailes III, PhD, GBA Advisor

My friends up in Maine came up with the concept of the Pretty Good House a few years ago, and I love the idea! Not everyone can or wants to build a LEED Platinum, Living Building Challenge, Passive House. But a lot of architects, builders, and home buyers would like to design, build, and live in houses that are better than the barely legal, code-minimum houses that populate the market.

The Best Way to Keep Your Attic Cooler is to Change Your Roof Color

Posted on August 26, 2015 by Allison A. Bailes III, PhD, GBA Advisor

The most contentious issue I’ve written about since I started blogging isn’t bad Manual Js. Nor is it endorsing government intervention by raising efficiency standards or improving energy codes. Incredibly, it’s not even whether or not naked people need building science. Nope.

How to Move Air Quietly Through a Duct System

Posted on August 19, 2015 by Allison A. Bailes III, PhD, GBA Advisor

At my first Building Science Summer Camp in 2011, David Hill gave a great presentation on some of the big problems with duct systems. (In case you weren’t reading this blog back then, I got myself invited with my 2010 article called I Don't Need No Stinkin' Building Science Summer Camp.)

Must the Three Pigs Die?

Posted on August 12, 2015 by Allison A. Bailes III, PhD, GBA Advisor

Building Science Summer Camp was last week. That means I was in Massachusetts with 500 of my closest friends, staying up too late, talking building science out the wazoo, and attending some great presentations from leaders in the world of building science.

Relative Humidity Doesn’t Tell You How Humid the Air Is

Posted on August 5, 2015 by Allison A. Bailes III, PhD, GBA Advisor

There's a problem with relative humidity. I hear it a lot when I talk to people about moisture problems. A client with high humidity in his home recently told me he didn't understand how it could be more humid inside his home than it was outdoors. The indoor relative humidity (RH) was 60% while it was only 50% outdoors. Do you see the problem?

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