The most recent blogs at Green Building Advisor

For years, the English-language website of the Passivhaus Institut in Germany provided this definition: “A 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. is a building in which a comfortable interior climate can be maintained without active heating and cooling systems. The house heats and cools itself, hence ‘passive.’”

Wait a second. Spring has barely sprung, and you’re saying we need to start thinking about energy audits already? What’s up with that?

There are several reasons why now is a good time not only to focus on energy auditing and weatherization work — not only for your clients, but also for your own home.

Amy Musser has a PhD in Architectural Engineering and, like me, used to be a college professor. Her husband, Matthew Vande, is an architect with an MS in Architectural Engineering. He is also a treehugger (see the black and white photo below). Together, they founded Vandemusser Design, a firm that provides green design, certification, and consulting.

In 2006, when we bought our house in Mamaroneck, New York, it was all about location: views on Mamaroneck Harbor, a south-facing orientation, proximity to the train station and the village’s main shopping street, and the ability to have a decent sailboat moored in deep water across the street and winterized at the shipyard next door.

Christopher Solar had a simple plan for an addition to his Ottawa home. The one-room structure would have a shed-style roof with a cathedral ceiling and vertical board siding. Solar liked a wall assembly he'd read about at GreenBuildingAdvisor, which consists of exterior foam, batt or blown insulation in the stud cavities and airtight drywall on the interior. An interior polyethylene vapor retarder never entered the picture.

And that's where his story gets complicated.

What’s the deal with thermal massHeavy, high-heat-capacity material that can absorb and store a significant amount of heat; used in passive solar heating to keep the house warm at night. ? Since manufacturers of materials that incorporate concrete often exaggerate the benefits of thermal mass, it’s easy to get cynical and conclude that the buzz around thermal mass is all hype. But in many climates, it’s actually useful to have a lot of thermal mass inside your house. Just keep in mind that thermal mass may not be as beneficial as its boosters pretend.

In my blog last week, I provided a little background on Tedd Benson and his evolution that ledLight-emitting diode. Illumination technology that produces light by running electrical current through a semiconductor diode. LED lamps are much longer lasting and much more energy efficient than incandescent lamps; unlike fluorescent lamps, LED lamps do not contain mercury and can be readily dimmed. him to found Unity Homes. This week, I’ll describe some of the features that set Unity Homes apart from both standard home construction and other panelized and manufactured home production.

One of the fundamental principles of building science is that buildings must be suited to their climate. When they're not, problems can ensue. Maybe it's just that they're not as efficient as they should be. Maybe it's worse.

Home energy audits in cold, northern climates are very different from those in hot climates. Different regions of the country have different types of housing stock, and there are regional variations in insulation methods and mechanical systems. In older houses, the type of weatherization work that has been performed varies greatly from region to region.

So the issues and energy priorities of northern houses are different from those of southern houses.

Construction projects are becoming more complex, with increasing levels of regulations, more product choices, and higher performance expectations. And there are so many more ways of getting bombarded with information — e-mail, text, voice-mail — that we get swept up into survival mode of responding to the bits of info as it comes along.

But the danger of this multi-tasking is that it doesn’t really work: you lose sight of the big picture (only seeing one piece of the elephant), and there is really no one who has a handle on the whole situation.