The most recent blogs at Green Building Advisor

Using Sand to Store Solar Energy

Posted on April 11, 2011 by Scott Gibson in Q&A Spotlight

John Klingel's question was simple enough: what's the best way of heating up a thick bed of sand beneath a concrete slab with PEXCross-linked polyethylene. Specialized type of polyethylene plastic that is strengthened by chemical bonds formed in addition to the usual bonds in the polymerization process. PEX is used primarily as tubing for hot- and cold-water distribution and radiant-floor heating. tubing? But the underlying issue — whether a sand bed is a good idea in the first place — quickly takes center stage in this Q&A post at GreenBuildingAdvisor.

Passivhaus, Part 2: The Standards

Posted on April 11, 2011 by Christopher Briley in Green Architects' Lounge

You can also subscribe to the Green Architects' Lounge on iTunes. That way, you'll never miss a show—and it's free.

Things You Can Learn from Pete’s Energy Bill

Posted on April 10, 2011 by Tristan Roberts in Energy Solutions

It turns out you can learn a thing or two from your fuel bill—and if you get fuel delivered, your delivery ticket.
But first, how cold a winter did you think it was? Or perhaps I should say, how cold has it been so far? I’m struggling to get a fire going this morning, and out my window there is two feet of snowpack still on the ground!

Visiting Passivhaus Job Sites in Washington State

Posted on April 8, 2011 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

On March 16, 2011, I flew to Seattle for a three-day visit to Washington state. Although the main purpose of my visit was to attend the spring conference of 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. Northwest, I devoted a day and a half to visiting Passivhaus buildings and construction sites in Seattle and Olympia. With the help of my gracious hosts, Dan Whitmore and Albert Rooks, I was able to see four Passivhaus sites and a large workshop where Passivhaus wall panels were being assembled indoors.

An Affordable Disappointment

Posted on April 5, 2011 by Carl Seville, GBA Advisor in Green Communities

If you had the “pleasure” of reading my first post for this blog, you read about and saw pictures of Felton Homes, the 100-unit affordable rehab project currently underway in Macon, Georgia.

Solar Decathlon 2011: Purdue University’s INhome

Posted on April 5, 2011 by Richard Defendorf in 2011 Solar Decathlon

Like most projects heading for the 2011 Solar Decathlon in Washington, D.C., Purdue University’s INhome is designed to address regional climate conditions and cultural expectations.

ACI 2011 National Home Performance Conference Wrap-Up

Posted on April 5, 2011 by Carl Seville, GBA Advisor in Green Building Curmudgeon

The ACI National Home Performance Conference was held in San Francisco, March 28-April 1, and I attended for the fourth consecutive year. It was my second year presenting. As this was the 25th anniversary of the event, I am still very much a newbie to this crowd, but now that I know many of the major players and have earned at least a little respect in the industry, I felt pretty comfortable. As always, ACI was a major geek fest with what appeared to be hundreds of different educational sessions running from 8 a.m.

How Much Radiation Does It Take 2 Kilomockingbird?

Posted on April 4, 2011 by Tristan Roberts in Energy Solutions

What is the measure of the time between slipping on a peel and hitting the pavement?

One bananosecond.

What is the ratio of an igloo’s circumference to its diameter?

Eskimo pi.

What is the metric equivalent of 1,000 aches?

1 megahurtz.

What is the metric equivalent of 2,000 mockingbirds?

2 kilomockingbirds.

How to Keep Garage Fumes Out of the House

Posted on April 4, 2011 by Scott Gibson in Q&A Spotlight

Jack Woolfe wants to build a small, airtight house with an attached garage. The house will have an exhaust-only ventilationMechanical ventilation system in which one or more fans are used to exhaust air from a house and make-up air is supplied passively. Exhaust-only ventilation creates slight depressurization of the home; its impact on vented gas appliances should be considered. system, meaning the system will expel stale air from the house without providing a specific source for replacement air.

That's one of several options for whole-house ventilation, but Woolfe is weighing the possible risks.

Are Passivhaus Requirements Logical or Arbitrary?

Posted on April 1, 2011 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

What follows is a reconstruction of Martin Holladay’s keynote address at the 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. Northwest conference in Olympia, Washington, on March 18, 2011. The piece has been fleshed out somewhat, in light of the fact that the original time constraints no longer apply. For the most part, each paragraph corresponds to one slide of the accompanying PowerPoint presentation.

Click here to view the presentation slides

Are Passivhaus requirements logical or arbitrary?

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