Musings of an Energy Nerd

Cut-and-Cobble Insulation

Posted on November 22, 2013 by Martin Holladay, GBA Advisor

Here at GBAGreenBuildingAdvisor.com, readers regularly ask about the best way to install rigid foam insulation between studs or rafters. A typical question might go like this: “I’d like to insulate between my studs with strips of 2-inch-thick polyisoPolyisocyanurate foam is usually sold with aluminum foil facings. With an R-value of 6 to 6.5 per inch, it is the best insulator and most expensive of the three types of rigid foam. Foil-faced polyisocyanurate is almost impermeable to water vapor; a 1-in.-thick foil-faced board has a permeance of 0.05 perm. While polyisocyanurate was formerly manufactured using HCFCs as blowing agents, U.S. manufacturers have now switched to pentane. Pentane does not damage the earth’s ozone layer, although it may contribute to smog. . I plan to cut the rigid foam pieces a little bit loose, and seal the edges of the polyiso with canned spray foam. Will this work?”

All About Embodied Energy

Posted on November 15, 2013 by Martin Holladay, GBA Advisor

What’s embodied energyEnergy that goes into making a product; includes energy required for growth, extraction, and transportation of the raw material as well as manufacture, packaging, and transportation of the finished product. Embodied energy is often used to measure ecological cost., and is there any reason to pay attention to it? Embodied energy is the energy it takes to manufacture building materials. Until recently, it was safe to advise builders that it wasn’t worth worrying about embodied energy, because the amount of energy (especially heating energy and cooling energy) used to operate a building over the building’s lifetime dwarfed the relatively small amount of energy embodied in the building materials.

Can Solar Power Solve the Coal Problem?

Posted on November 8, 2013 by Martin Holladay, GBA Advisor

I recently read a New York Times article on the coal problem. In the future, the article notes, we won’t be able to burn coal at our current rate, so there is an obvious need to make a transition to alternative sources of energy. According to the Times article, the most likely replacement for coal is solar energy.

Monitoring Moisture Levels in Double-Stud Walls

Posted on November 1, 2013 by Martin Holladay, GBA Advisor

Most wood-framed buildings have no insulation on the exterior side of the 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. . That means that the wall sheathing gets cold and wet during the winter.

Low-Road Buildings Are Homeowner-Friendly

Posted on October 25, 2013 by Martin Holladay, GBA Advisor

There are at least two recognizable camps in the green building community. The older camp includes hippies, owner/builders, and those in the natural building movement. These builders prefer to scrounge materials from the woods or demolition sites rather than purchase new materials from a lumberyard. Their homes might be made of adobe, logs, or straw bales.

Martin’s Energy Quiz — Third Edition

Posted on October 18, 2013 by Martin Holladay, GBA Advisor

GBAGreenBuildingAdvisor.com published an energy quiz in 2009, and another one in 2011. It looks like we're overdue for another installment.

Answers are provided at the bottom of this column; don't peek until you've finished the quiz.

1. True or false: In freezing climates, a drainback solar hot water system circulates ordinary water (without any antifreeze) through its solar collectors.
(a) True.
(b) False.

All About Radon

Posted on October 11, 2013 by Martin Holladay, GBA Advisor

Several colorless, odorless gases can injure your health. For example, carbon monoxide can kill you in minutes. RadonColorless, odorless, short-lived radioactive gas that can seep into homes and result in lung cancer risk. Radon and its decay products emit cancer-causing alpha, beta, and gamma particles. takes longer — usually decades — to kill you, and (fortunately) death is less certain.

A Backyard Test of Peel-and-Stick Flashings

Posted on October 4, 2013 by Martin Holladay, GBA Advisor

More than 12 years ago, I wrote an article on peel-and-stick window flashing. The article, “Choosing Flexible Flashings,” appeared in the June 2001 issue of The Journal of Light Construction (JLC).

Fixing a Wet Basement

Posted on September 27, 2013 by Martin Holladay, GBA Advisor

A hundred years ago, homes had cellars, not basements. The typical cellar has stone-and-mortar walls and a dirt floor. Such a cellar is cool and humid, so it's the perfect place to store carrots and potatoes. If a cellar floor got wet during the spring thaw, no one cared. After all, it’s not as if anyone was playing ping pong down there.

Air Sealing an Attic

Posted on September 20, 2013 by Martin Holladay, GBA Advisor

If you want to improve the energy performance of an older house, one of the first steps is to plug your attic air leaks. Although many GBAGreenBuildingAdvisor.com articles address aspects of attic air sealing, no single article provides an overview of the topic. This article is an attempt to provide that missing overview.

I’ll try to explain how you can seal air leaks in a conventional vented, unconditioned attic. If your house has cathedral ceilings — that is, insulated sloped roof assemblies — the air sealing tips in this article don’t apply to your house.

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