Musings of an Energy Nerd

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.

Calculating the Global Warming Impact of Insulation

Posted on May 27, 2011 by Martin Holladay, GBA Advisor

In June 2010, Alex Wilson published a ground-breaking article, “Avoiding the Global Warming Impact of Insulation,” in Environmental Building News. In the article, Wilson examined the implications of the fact that the HFC blowing agents used to make extruded polystyrene (XPSExtruded polystyrene. Highly insulating, water-resistant rigid foam insulation that is widely used above and below grade, such as on exterior walls and underneath concrete floor slabs. In North America, XPS is made with ozone-depleting HCFC-142b. XPS has higher density and R-value and lower vapor permeability than EPS rigid insulation.) and most types of closed-cell spray polyurethane foam have a much greater global warming impact than CO2.

Nailing Window Flanges Through Foam

Posted on May 20, 2011 by Martin Holladay, GBA Advisor

Over 30 years ago, when builders first began installing rigid foam wall 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. , they had to figure out their own methods of fastening flanged windows. In 1982, when I sheathed my house with 1-inch-thick EPSExpanded polystyrene. Type of rigid foam insulation that, unlike extruded polystyrene (XPS), does not contain ozone-depleting HCFCs. EPS frequently has a high recycled content. Its vapor permeability is higher and its R-value lower than XPS insulation. EPS insulation is classified by type: Type I is lowest in density and strength and Type X is highest., I installed “picture frames” of 1-inch lumber around each window rough opening. As it turned out, Joe Lstiburek was also building a foam-sheathed house in 1982, but he used a different approach.

Building an Unvented Crawl Space

Posted on May 13, 2011 by Martin Holladay, GBA Advisor

Residential foundations vary widely from one corner of the U.S. to another. Builders in some regions love basements, while builders in other regions swear by slabs on grade. Although most builders have a theory to explain these regional preferences, the main reason for these variations is habit, not logic. In areas of the country where basements are rare, there usually aren’t any technical barriers to building basements; and up north, where basements rule, it’s perfectly possible to build on a slab.

Alternatives to Clothes Dryers

Posted on May 6, 2011 by Martin Holladay, GBA Advisor

UPDATED on 9/17/2012 with new information on dehumidifiers for clothes-drying rooms.

In an American home with a relatively new refrigerator, the clothes dryer usually uses more energy than any other home appliance. An electric clothes dryer draws between 4,000 and 6,000 watts, and costs about 60 cents an hour — about $158 per year, on average — to operate. While a gas dryer may only draw 400 watts of electricity, it also consumes a significant amount of natural gas or propane to dry each load of laundry.

Can ‘Passive House’ Be Trademarked?

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

UPDATED on 4/3/2012

Can the phrase “passive house” be trademarked? If the answer is yes, has any organization claimed the trademark yet?

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