Musings of an Energy Nerd

Zero-Energy Construction is ‘Set to Explode’

Posted on February 24, 2017 by Martin Holladay

California regulators have established an ambitious policy goal: Beginning in 2020, all new homes in the state must be designed for net-zero-energy operation. (GBAGreenBuildingAdvisor.com has published at least four news stories on California's net-zero target: here, here, here, and here.)

Comparing Carpentry Tools to Surgical Tools

Posted on February 17, 2017 by Martin Holladay

Two hundred years ago, a ship's carpenter had many duties. In addition to repairing the ship, a carpenter would be called on to perform emergency amputations. Why? He was the one who had the saws.

Modern surgeons still require saws, as well as drills, chisels, scrapers, and grinders. As a lighthearted exercise that has almost nothing to do with green building, I recently got the idea to compare surgical tools with carpentry tools.

Full disclosure: This blog is for fun. It is completely empty of any building science.

GBA Prime Sneak Peek: Fine Homebuilding Editors Interview Martin Holladay

Posted on February 10, 2017 by Martin Holladay

My fellow editors at Fine Homebuilding — Justin Fink, Rob Yagid, and Brian Pontolilo — have been hosting a weekly podcast for several months. They recently invited me to join them in a sound studio at the Fine Homebuilding office to record a conversation on a variety of building science topics.

This week, I'm taking a break from my usual blog-writing schedule, substituting a two-part podcast recording. Click on one of the green triangles to start listening.

Bill Rose’s Building Science To-Do List

Posted on February 3, 2017 by Martin Holladay

William Rose is fun to listen to. The author of a landmark book, Water in Buildings, Rose is a research architect at the University of Illinois at Urbana-Champaign and a widely respected building scientist.

Rose’s speaking style is discursive, meandering, hesitant, and occasionally poetic. He shares historical anecdotes that sometimes seem only remotely relevant to his topic. Eventually, however, he sews together a patchwork quilt with a unified theme.

In Search of a DIY Guide to Rooftop PV

Posted on January 27, 2017 by Martin Holladay

Most new grid-tied 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.) systems are installed by solar contractors. Here’s what usually happens: the homeowners call up a few local solar companies; representatives come to the house to make a site assessment; the homeowners choose the contractor whose quote sounds reasonable and sign a contract for the work. The homeowners don’t even have to put up a ladder; all they have to do is sign a check.

Slow Progress on New Blowing Agents for Polyiso

Posted on January 20, 2017 by Martin Holladay

R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. tests by the National Roofing Contractors Association and the Building Science Corporation have revealed that the thermal performance of polyisocyanurate is greatly reduced at cold temperatures. While the R-value of polyiso at a mean temperature of 75°F might be about R-5.7 per inch, the effective R-value of the polyiso drops to about R-4.8 per inch at a mean temperature of 25°F.

Building Science Information for Builders

Posted on January 13, 2017 by Martin Holladay

Jacob Deva Racusin, a Vermont builder and educator, has just written a book called Essential Building Science. The book aims to provide builders — especially so-called “natural builders” — with a basic understanding of the ways that heat and moisture flows affect residential buildings. (The book is available from New Society Publishers for $34.95.)

Windwashing in Exterior Mineral Wool

Posted on January 6, 2017 by Martin Holladay

Fibrous insulation materials like mineral wool do not stop air flow. Unlike rigid foam (which is a pretty good air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both., as long as the seams between panels are taped), mineral wool can only slow down air flow, not stop it.

So what happens when builders install mineral wool insulation on the exterior side of 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. ? Is the thermal performance of the mineral wool degraded by wind?

R-Value Scammers Sued By the FTC

Posted on December 30, 2016 by Martin Holladay

Here at GBAGreenBuildingAdvisor.com, we received our first inquiry concerning Insultex housewrap on July 31, 2015, when Marcus Sheffer questioned the validity of Insultex’s R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. claims.

Insultex is a plastic housewrap distributed by Innovative Designs of Pittsburgh, Pennsylvania. The company offers two versions of its housewrap, at a price that is from two to nine times higher than the price of ordinary housewrap. One version is 1 mm (0.0384 inch) thick; according to Innovative Designs, this product has an R-rating of R-3. That’s R-78 per inch.

Songs for Christmas 2016

Posted on December 23, 2016 by Martin Holladay

Donald Trump’s Song

Oh, the weather outside is frightful,
But the new AC is delightful,
I’ll tell you what I’ve always felt:
Let it melt! Let it melt! Let it melt!

Polar bears these days are thinking
That the ice cap seems to be shrinking,
I’ll tell you what I’ve always felt:
Let it melt! Let it melt! Let it melt!

The heat shows no signs of stopping,
And the corn in the fields is popping,
I’ll tell you what I’ve always felt:
Let it melt! Let it melt! Let it melt!

We expect a most wild ride,
Because it’s so hot outside,

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