Musings of an Energy Nerd

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.

Visiting Energy-Smart Designers and Builders in Maine

Posted on June 24, 2011 by Martin Holladay, GBA Advisor

I recently spent a couple of days in Maine, where I visited with an active group of energy-conscious architects and builders. My tour of seven job sites facing Casco Bay in the Atlantic Northeast nicely balanced my tour of several job sites facing the Puget Sound in the Pacific Northwest in March.

Helping People With Multiple Chemical Sensitivity

Posted on June 17, 2011 by Martin Holladay, GBA Advisor

If you are a designer or builder specializing in green building, it’s only a matter of time before you are approached by a client who suffers from multiple chemical sensitivity. A typical request might go like this: “Many ordinary building materials can make me sick. I’m looking for someone to design (or build) me a house without any toxic chemicals.”

What’s the best way to respond to such a potential customer? To answer this question, let’s turn first to the medical experts.

How Is a Home’s HERS Index Calculated?

Posted on June 10, 2011 by Martin Holladay, GBA Advisor

Anyone involved with the Energy Star HomesA U.S. Environmental Protection Agency (EPA) program to promote the construction of new homes that are at least 15% more energy-efficient than homes that minimally comply with the 2004 International Residential Code. Energy Star Home requirements vary by climate. program has probably heard of the HERSIndex or scoring system for energy efficiency established by the Residential Energy Services Network (RESNET) that compares a given home to a Home Energy Rating System (HERS) Reference Home based on the 2006 International Energy Conservation Code. A home matching the reference home has a HERS Index of 100. The lower a home’s HERS Index, the more energy efficient it is. A typical existing home has a HERS Index of 130; a net zero energy home has a HERS Index of 0. Older versions of the HERS index were based on a scale that was largely just the opposite in structure--a HERS rating of 100 represented a net zero energy home, while the reference home had a score of 80. There are issues that complicate converting old to new or new to old scores, but the basic formula is: New HERS index = (100 - Old HERS score) * 5. Index, a method of scoring the energy efficiency of a new or existing home. A Web page maintained by the state of Arkansas, for example, explains that the “EPA requires a house qualifying for Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. to be built with best practices, tight ducts, and at least 15% more energy efficient than code as shown by a HERS Index score of 85 or less as determined by a HERS Rater.”

New Air Sealing Requirements in the 2009 International Residential Code

Posted on June 3, 2011 by Martin Holladay, GBA Advisor

One of the most cost-effective ways of lowering residential energy costs is to reduce a home’s air leakage rate, so it makes sense for energy codes to ratchet up air-sealing requirements. The latest (2009) version of the International Residential Code does exactly that.

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