Musings of an Energy Nerd

Who Can Perform My Load Calculations?

Posted on March 24, 2017 by Martin Holladay

To design a residential heating or cooling system, the first step is to perform a load calculation. (A load calculation determines the size of a building’s heating loadRate at which heat must be added to a space to maintain a desired temperature. See cooling load. on one of the coldest nights of the year and the size of a building’s cooling load on one of the hottest afternoons of the year.) It’s important to know the size of these loads to determine the size of the required heating and cooling equipment.

Installing Closed-Cell Spray Foam Between Studs is a Waste

Posted on March 17, 2017 by Martin Holladay

Open-cell spray foam has an R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of about R-3.7 per inch, while closed-cell spray foam has an R-value that may be as high as R-6.5 per inch. If you want to install spray foam in a stud wall, and price is no object, then it would seem to make sense to specify closed-cell spray foam, right?

Not necessarily.

A Visit to a LEED Platinum Office Building

Posted on March 10, 2017 by Martin Holladay

While I’ve designed a few single-family homes, I’m well aware that designing a high-rise office building is a whole ’nother kettle of fish. The challenge is far greater — at least an order-of-magnitude greater — requiring an experienced team that includes architects, structural engineers, mechanical engineers, and energy consultants.

Three Superinsulated Houses in Vermont

Posted on March 3, 2017 by Martin Holladay

Efficiency Vermont, a nonprofit agency that provides financial incentives for energy-efficiency improvements by homeowners, builders, and businesses in Vermont, has developed a certification program for new homes called the High Performance Certification.

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.

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