The most recent blogs at Green Building Advisor

Before I even get started, I want to point out that I am no expert on ventilation. I have learned a lot from (and rely on) many experts, including Paul Raymer, Gord Cooke, John Krigger, Joe Lstiburek, Armin Rudd, and Terry Brennan, among others. I depend on them to fuss about the details of how much ventilation a house needs.

A GBAGreenBuildingAdvisor.com reader who calls himself “Mr. Mike” is working on an 11-ft. by 14-ft. addition to his house in central New York that sits some 5 feet off the ground. The space beneath the addition is a great place to park a lawnmower, but it's also open to the cold.

My grandfather, William L. Holladay, was a refrigeration and cooling engineer. Decades ago, he wrote a pioneering, speculative article on ground-source heat pumps, “The Heat Pump: What it does, and what it may do someday.” The article appeared in the October 1948 issue of Engineering and Science Monthly. (For a basic explanation of how a heat pump works, and the difference between an air-source heat pumpHeat pump that relies on outside air as the heat source and heat sink; not as effective in cold climates as ground-source heat pumps. and a ground-source heat pump, see Heat Pumps.)

I love many things about Kansas — from the tall-grass prairies in the Flint Hills where I’ve hiked through rolling hills overlooking grazing bison to the dramatic waterfowl migrations in the Cheyenne Bottoms region in the western part of the state.

Really, the argument about whether you should vent a crawl space in a humid climate is over. Advanced Energy's research project from 2002 proved that closed crawl spaces outperform vented crawl spaces.

A quick look at the psychrometric chart below shows that the argument should never have existed in the first place. (Click the image to see an enlarged version.)

[Editor’s note: Liz Johndrow is a natural builder who specializes in the use of cob, strawbale, adobe, earthbag, and earthen plasters. During the winter months, she volunteers in Nicaragua, where she works with villagers, especially women, on construction projects in Sabana Grande, Totgalpa. What follows is a sample of Johndrow’s blog entries written from Nicaragua. You can learn more about her work at her website, Earthen Endeavors.]

Posted April 1, 2013

With the arrival of spring and new plant growth springing up all around, I’ve begun to reflect on my several years of writing this blog post, and I have come to the conclusion that far too often I have been overly critical and close-minded about many things. In addition, I have championed some theories and causes that contradicted many long-standing traditions in design, construction, and renovation. And it’s time to say I’m sorry.

Stuffy homes are unhealthy homes, while homes with plenty of fresh air are healthy. That’s been a commonly held belief for at least 200 years. In the mid-19th century, the connection between ventilation and human health was championed by sanitarians, a group of health experts who blamed the spread of bubonic plague and cholera on “miasma.”

What do you do if you’re a builder and your client (that would be me) hands you a material that no one’s ever heard of, let alone installed in this country, and asks you to insulate his house with it? A lot of smart builders would run the other way. Eli Gould, our partner in the Dummerston, Vermont farmhouse we’re renovating (really re-building), took it on as a challenge.

I was a kid a long, long time ago. Seems like it was another century ... another millennium even. Wait a minute — it was another millennium!

That was back in the day when we used to ride bicycles without helmets, apply mercury to our wounds, move seat belts out of the way (if the car even had them), and put our tongue on steel poles in the middle of winter. Of course, in Texas and Louisiana we just ended up with a bad taste in our mouth from those steel poles and wondered why people made such a big deal about it.