Musings of an Energy Nerd

The Energy Nerd's Greatest Hits

Posted on June 18, 2010 by Daniel Morrison

Martin is enjoying what may be one of his last opportunities for a family vacation; his oldest son is winding down his high school career, and will leave for college in about a year. All of us at Green Building Advisor support his strong family values and hope he has a great time vacationing on the island of Crete for the next couple of weeks.

Using Ceiling Fans To Keep Cool Without AC

Posted on June 11, 2010 by Martin Holladay, GBA Advisor

When I was a young backpacker traveling through India, Sri Lanka, and Thailand in the 1970s, I couldn’t afford air-conditioned hotels or restaurants. In these tropical conditions, I became quite accustomed to the benefits of Casablanca-style fans.

Although a fan can’t lower the temperature of the air, it can make people feel cooler. Moving air accelerates the rate at which perspiration evaporates from your skin. The evaporation process requires heat, so increased evaporation means that more heat is leaving your body.

Should Green Homes Burn Wood?

Posted on June 4, 2010 by Martin Holladay, GBA Advisor

Environmentalists often argue over the wisdom of heating homes with wood. Strong arguments can be marshaled on both sides of this debate, so I’ll do my best to represent both positions before summing up.

Housewrap in a Can: Liquid-Applied WRBs

Posted on May 28, 2010 by Martin Holladay, GBA Advisor

When it’s time to cover 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. with a water-resistive barrierSometimes also called the weather-resistive barrier, this layer of any wall assembly is the material interior to the wall cladding that forms a secondary drainage plane for liquid water that makes it past the cladding. This layer can be building paper, housewrap, or even a fluid-applied material. (WRB), most residential builders choose plastic housewrap, asphalt felt, building paperTypically referring to Grade D building paper, this product is an asphalt-impregnated kraft paper that looks a lot like a lightweight asphalt felt. The Grade D designation has come to mean that the building paper passes ASTM D779 (minimum 10-minute rating with the “boat test”) and different products are called out as “30-minute” or even “60-minute” based on D779 results. At times confused with roofing felt, roofing felts and building paper differ in two ways: felts are made of recycled-content paper, building papers of virgin paper; felts are made of a heavier stock paper; building papers a lighter stock. See also roofing felt., or rigid foam sheathing. Some commercial builders, however, choose a fifth option: a liquid-applied building wrap.

Liquid-applied WRBs come in a bucket and are applied to wall sheathing or concrete blocks with a roller or a spray rig. These products cure to form a tenacious, flexible coating that seals small cracks and penetrations.

Testing a Thirty-Year-Old Photovoltaic Module

Posted on May 21, 2010 by Martin Holladay, GBA Advisor

In 1980, after living in the woods of Vermont without electricity for five years, I bought my first photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. (PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.) module. Responding to a small ad in Mother Earth News, I sent a check to Joel Davidson, a back-to-the-land urban refugee who was facilitating a bulk purchase of PV panels. From his off-grid acreage in Pettigrew, Arkansas, Davidson was selling 33-watt Arco Solar modules for $275 each.

Many people ask, “How long do solar panels last?” To mark the 30th anniversary of my first PV module, I decided to climb up on my roof and bring it down for testing.

A Leaky Old House Becomes a Net-Zero Showcase

Posted on May 14, 2010 by Martin Holladay, GBA Advisor

Jane Bindley had a dream: to turn her 1978 ranch in central New Hampshire into a net-zero-energy house. How hard could that be?

As it turned out, pretty hard. But with help from a dedicated team of experts and a generous budget, Bindley achieved her dream.

Best Construction Details for Deep-Energy Retrofits

Posted on May 7, 2010 by Martin Holladay, GBA Advisor

A collection of experts working on deep-energy retrofits recently attended a brainstorming session to share design tips and propose topics for further research.

The conference, formally titled the “Expert Meeting for Details for Deep Energy Retrofits,” was held in Boston on March 12. The meeting was funded by the Department of Energy’s Building America program and hosted by the Building Science Corporation.

Energy-Efficiency Retrofits: Insulation or Solar Power?

Posted on April 29, 2010 by Martin Holladay, GBA Advisor

For our country to achieve the carbon emission reductions necessary to avoid a planetary catastrophe, many experts contend that almost every house in the country will need to have retrofit work that achieves deep cuts in energy use.

There’s a major stumbling block, however: deep energy retrofits are frighteningly expensive —in the range of $80,000 to $250,000 per house. With costs so high, many homeowners are asking: how long is the payback period for a deep-energy retrofit?

Building Houses and Saving Energy in Nicaragua

Posted on April 26, 2010 by Martin Holladay, GBA Advisor

There's a reason this week's blog is late: I just returned from a week in Nicaragua.

I'm posting a few photos from Central America. My next blog should appear on schedule at the end of the week.

A ‘Magic Box’ For Your Passivhaus

Posted on April 16, 2010 by Martin Holladay, GBA Advisor

By designing a tight envelope with thick insulation, Passivhaus designers work hard to whittle a home’s space heating load to a bare minimum. Many European designers strive to get the heating load so low that all space heat can be provided by raising the temperature of the ventilation air.

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