The most recent blogs at Green Building Advisor

The Science of Global Warming Is Older Than Quantum Mechanics

Posted on March 6, 2013 by Allison A. Bailes III, PhD in Building Science

I'm new to global warming. I didn't hear about it until 1983. Even thirty years ago, the science behind the greenhouse effect and global warming was well known. French Physicist and mathematician Joseph Fourier is generally credited with being the first to hypothesize that the earth is warmed by its atmosphere and even that we humans can change the climate. That goes all the way back to 1827.

Is R-Value Dead as a Dodo?

Posted on March 5, 2013 by Erik North in Guest Blogs

Once upon a time, house insulation meant an extra sweater — and stop your damn complaining. Men were men, women were women, and cats and dogs were cats and dogs, I assume. Houses included features to produce and retain heat, of course — things like double back-plaster walls and central chimneys. But until the 20th century, insulation barely existed in any formal sense.

Finished Foundation and Floor Framing Uh-Ohs

Posted on March 4, 2013 by Roger Normand in Guest Blogs

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the 24th article in a series that will follow their project from planning through construction.]

All About Rainscreens

Posted on March 1, 2013 by Martin Holladay in Musings of an Energy Nerd

UPDATED on December 20, 2016 with new product information

Twenty years ago, very few residential builders knew what a rainscreenConstruction detail appropriate for all but the driest climates to prevent moisture entry and to extend the life of siding and sheathing materials; most commonly produced by installing thin strapping to hold the siding away from the sheathing by a quarter-inch to three-quarters of an inch. was. These days, however, it’s no longer unusual to see siding being installed on vertical furring strips or a plastic drainage mat. As rainscreens become more common, mainstream builders are beginning to ask, “What’s a rainscreen? How do I know if I need one?”

This article will pull together information to answer the most common questions about rainscreen gaps between siding and sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. .

How to Choose the Right Mechanical System

Posted on February 28, 2013 by Christopher Briley in Green Architects' Lounge

With any house, there are so many variables that influence the decision to choose one particular mechanical system over another: climate, house size, cost, local availability and cost of fuels and materials, and the lifestyle and preferences of the occupants. There is no “one-size-fits-all” system that we can reliably prescribe for all projects. Phil and I sat down over a good winter cocktail to share our views, anecdotes, battle scars, and wisdom on this important subject.

Will Natural Gas Be Our Domestic Energy Savior?

Posted on February 27, 2013 by Alex Wilson in Energy Solutions

In many parts of the country and for many applications, natural gas is considered a panacea to our energy challenges.

Should the Paper Facing of Batt Insulation Face the Inside or Outside?

Posted on February 27, 2013 by Allison A. Bailes III, PhD in Building Science

If you install fiberglass batt insulationInsulation, usually of fiberglass or mineral wool and often faced with paper, typically installed between studs in walls and between joists in ceiling cavities. Correct installation is crucial to performance. * with a kraft paper vapor retarder in a home, which way do you face the vapor retarder? To the inside of the home or the outside of the home? For many building science questions, the answer is, “It depends.” For this one, however, the answer is clear.

SPOILER ALERT: The answer is in the next paragraph — so if you'd rather wait and find out when you see the movie in the theater, don't read any further.

Good Ducts, Bad Ducts

Posted on February 26, 2013 by Carl Seville in Green Building Curmudgeon

Whether they actually do it or not, I think almost everyone involved in high performance buildings recognizes that the best place to put our ducts is inside conditioned spaceInsulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort. . Most builders in my area haven’t made the change, and with the exception of the occasional house with an insulated basement, they still put most air handlers and ducts in the attic.

Choosing the Right Wall Assembly (2013)

Posted on February 25, 2013 by Scott Gibson in Q&A Spotlight

Michael Roland is designing a new house and trying to choose the right wall assembly. It’s down to a choice between a double-stud wallConstruction system in which two layers of studs are used to provide a thicker-than-normal wall system so that a lot of insulation can be installed; the two walls are often separated by several inches to reduce thermal bridging through the studs and to provide additional space for insulation. filled with fluffy insulation, or a single wall wrapped in a layer of rigid foam insulation.

Ductless Minisplit Performance During Cold Weather

Posted on February 22, 2013 by Marc Rosenbaum in Guest Blogs

I tried an experiment this week during our cold snap. We've kept the door closed to the first floor ell (bedroom and bath) and let it run cold, because the Fujitsu wasn't sized to heat that space too. I opened the door early in the cold snap, and let the heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump. go, leaving it set on 70°F. What I found was that overnight the main space went to 66°F, and the upstairs and back bedroom were 3° to 4°F lower.

My calculated heat loss in these conditions is about 24,000 BTUBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. /hour, and the heat pump is rated at about 17,000 BTU/hour at about 10°F. You'd think it would not be able to keep up.

Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!