Musings of an Energy Nerd

Spray Foam Jobs With Lingering Odor Problems

Posted on September 2, 2011 by Martin Holladay, GBA Advisor

Should spray polyurethane foam be installed in an occupied house? Hundreds of spray foam contractors around the country are happy to answer “Yes!” In almost all cases, these jobs end successfully: the spray foam improves the home’s thermal performance and the homeowner is happy.

Installing Mineral Wool Insulation Over Exterior Wall Sheathing

Posted on August 26, 2011 by Martin Holladay, GBA Advisor

A subset of green builders have always been grumpy about foam. Such builders look at rigid foam panels and spray foam as suspect products: they are made from petroleum, laced with mysterious chemicals, and impermeable to vapor flow.

A Bold Attempt to Slay R-Value

Posted on August 19, 2011 by Martin Holladay, GBA Advisor

R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. is the poor stepchild of building science metrics. Although it is often essential for builders, designers, and engineers to know a material’s R-value, this useful metric is regularly abused, derided, and ridiculed for its shortcomings. “R-value doesn’t measure assembly effects: thermal bridges, air movement, 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. , moisture content — all of which can all affect thermal properties,” explained Chris Schumacher, an engineer and researcher at Building Science Corporation, at a summer symposium in 2009. “R-value doesn’t do a good job describing the entire system.”

Insulating Old Brick Buildings

Posted on August 12, 2011 by Martin Holladay, GBA Advisor

UPDATED March 19, 2015

Older buildings with load-bearing brick walls are common in many northern U.S. cities. While these thick (muti-wythe) brick walls were often plastered on the interior, they were rarely insulated.

Utility-Scale Wind Turbines

Posted on August 5, 2011 by Martin Holladay, GBA Advisor

I live in Wheelock, Vermont, a town with 598 residents. Our town is so small that we have neither a post office nor a zip code. To get my mail, I have to travel two miles to the post office in Sheffield, our larger neighbor. (Sheffield has a population of 704.)

There’s a $90 million construction project underway in Sheffield this summer. In its entire 200-year history, the sleepy town has never seen anything like this.

Straw-Bale Walls

Posted on July 29, 2011 by Martin Holladay, GBA Advisor

Do you want to build your home out of natural materials? If so, you can build your walls with adobe, cob, cordwood, rammed earth, or wattle-and-daub. Although all of these walls have a long history, their thermal performance is poor. If you want a well-insulated wall, one natural material is the clear winner: straw bales.

A 23-inch-thick straw-bale wall has an R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of about R-33. Moreover, since virtually all straw-bale walls are plastered on both sides, these walls are relatively airtight.

All About Larsen Trusses

Posted on July 22, 2011 by Martin Holladay, GBA Advisor

A Larsen truss is a type of wall truss used to build a thick wall — thick enough to provide room for above-average amounts of insulation. It was developed in 1981 by John Larsen, a builder in Edmonton, Alberta.

In honor of the 30th anniversary of the Larsen truss, the time has come for a definitive article on the invention. This report includes an interview with the inventor of the Larsen truss, a history of its use, and a discussion of its advantages and disadvantages.

Job Sites in Maine, Part Three

Posted on July 15, 2011 by Martin Holladay, GBA Advisor

To end my three-part report on my trip to Maine, I’ll describe my visits to two new energy-efficient homes — an elegant home in Freeport, and a compact 1,000-square-foot home in Bath.

The Freeport home was designed by architect Chris Briley and built by Dan Kolbert. Since the owners of the home haven’t moved in yet, the rooms are still empty of furniture.

An ‘Insulating’ Paint Salesman Is Tripped Up By His Own Product

Posted on July 8, 2011 by Martin Holladay, GBA Advisor

There is no such thing as “insulating” paint, as I noted in an earlier blog. However, that fact hasn’t stopped paint dealers from promoting these worthless high-priced coatings to gullible customers.

More Job Site Visits in Maine

Posted on July 1, 2011 by Martin Holladay, GBA Advisor

On my second day in Maine, I toured seven energy-efficient buildings in various stages of construction. In last week’s blog, I reported on my visit to Richard Renner’s office and Jesse Thompson’s house. This blog picks up the story with a report on my visit to three sites: an ongoing deep-energy retrofit project, a new home in Falmouth, and an unusual co-housing project.

If you're the type of reader who prefers pictures to words, you're in luck: this week's blog is loaded with photos.

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