Musings of an Energy Nerd

Martin’s Energy Quiz

Posted on December 18, 2009 by Martin Holladay

This week’s blog is an energy efficiency and building science quiz. Remember, using Google for research is cheating. Answers are at the bottom of the page.

1. During the winter, a home inspector climbs into an attic and notices that the underside of the roof sheathing is covered with frost and the rafters have stains indicating mold. The most likely cause of these problems is:
a. A roof leak
b. Insufficient insulation on the attic floor
c. Air leakage paths between the wet basement and the attic.
d. Bats or squirrels.

Windows That Perform Better Than Walls

Posted on December 11, 2009 by Martin Holladay

UPDATED on March 18, 2015

The common perception that windows are “energy holes” is a bad rap. Since today’s high-solar-gain triple-glazed windows gather more heat than they lose, good windows perform better than an insulated wall. After all, a wall can only lose energy, while windows can gain energy during the day to balance energy lost at night.

Roofing and Siding Jobs Are Energy-Retrofit Opportunities

Posted on December 4, 2009 by Martin Holladay

Unlike governments in Germany and the U.K., the U.S. government hasn’t yet enacted an energy policy aimed at addressing global climate change. As a result, prices for carbon-based fuels in the U.S. are far lower than in most European countries.

If Americans continue along our current energy path, wrenching climate change is almost inevitable. That’s why many energy experts advise Americans to prepare for the eventual implementation of steep carbon taxes on heating fuel and electricity.

One prominent environmental organization, the Union of Concerned Scientists, has called for an 80% reduction in U.S. greenhouse gas emissions by 2050, and two states (California and New Jersey) have adopted that target as a state goal. The 2030 Challenge, a program endorsed by the American Institute of Architects, sets a goal of implementing energy retrofits designed to reduce energy use by 50% at 1.5 million U.S. homes annually between now and 2030.

It's unclear whether the U.S. will be able to meet these challenging targets. But attaining the targets would require almost every U.S. home to under a deep-energy retrofit. In most cases, the work would require walls and roofs to be covered with a thick layer of exterior insulation.

The logical time to do this work is when siding or roofing is replaced.

Houses Versus Cars

Posted on November 27, 2009 by Martin Holladay

You’re striving to minimize your carbon footprintAmount of carbon dioxide and other greenhouse gases that a person, community, industry, or other entity contributes to the atmosphere through energy use, transportation, and other means. , and your house is energy efficient. Through diligent conservation efforts, you’ve greatly reduced the amount of natural gas and electricity required to run your home.

Bravo! But how does your residential energy budget compare to your transportation energy budget? You may be happy to brag about your low utility bills — but if you’re anything like me, you’re probably a little ashamed of your gasoline budget.

Resisting the Allure of Small Wind Turbines

Posted on November 20, 2009 by Martin Holladay

Wind turbines have a hypnotic allure. The Siren call of carbon-neutral electricity has led many environmentalists to dream of owning a backyard wind turbine.

Unfortunately, small wind turbines, unlike utility-scale wind turbines, are rarely cost-effective, even when installed at a good site. Installed at an average site, a wind turbine is little more than an expensive toy.

Backyard Wind Turbines

Posted on November 20, 2009 by Martin Holladay

Manufacturers of small wind turbines are enjoying a boom. Fascinated by the idea of generating their own electricity, many rural homeowners have invested thousands of dollars — sometimes tens of thousands of dollars — in a backyard wind generator.

Ten Ways to Improve a New Home

Posted on November 13, 2009 by Martin Holladay

Buying an inefficient refrigerator is an expensive mistake. But at least the solution is simple: you can always buy a new refrigerator.

If you build an inefficient house, however, you may have an unfixable problem on your hands. Some newly built homes are so poorly designed, sited, and built that it would be cheaper to demolish them and start again than to correct all their flaws.

Heating a Tight, Well-Insulated House

Posted on November 6, 2009 by Martin Holladay

UPDATED on March 2, 2017 with information on the Dettson furnace rated at 15,000 BtuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. /h.

If you build a small, tight, well-insulated home — in other words, a green home — it won’t need much heat. Since typical residential furnaces and boilers are rated at 40,000 to 80,000 Btuh, they are seriously oversized for a superinsulated home, which may have a heating design load as low as 10,000 to 15,000 Btuh.

Deciphering the Tax Credits

Posted on October 30, 2009 by Martin Holladay

The energy-efficiency tax credits and renewable-energy tax credits are better than tax deductions. The allowable credits aren’t just deductible expenses; they represent dollars subtracted directly from your tax bill. While the tax credit program includes illogical rules, the available tax credits can be significant.

If you want to claim a tax credit on your 2009 income tax return for energy-efficiency improvements to your home, you should get the improvements installed before the end of the year. There’s really no need to rush, however, since the tax credits will remain available until the end of 2010 — or, in some cases, 2016.

Passivhaus Crosses the Atlantic

Posted on October 23, 2009 by Martin Holladay

Last weekend I attended the Fourth Annual North American Passive House Conference in Champaign-Urbana, Ill. The conference offered a great opportunity to learn more about the Passivhaus standard and to discuss low-energy buildings with an experienced group of architects, engineers, and builders.

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