Musings of an Energy Nerd

A Caribbean Island Transitions to PV

Posted on December 16, 2016 by Martin Holladay

Most of the electricity generated in the U.S. comes from power plants that burn coal or natural gas. Although an increasing percentage of our electricity comes from 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.) arrays and wind turbines, there are two problems with these renewable energy sources. First, electricity generated by PV arrays or wind turbines is still somewhat more expensive than electricity generated by fossil fuel plants (although the cost of solar and wind continue to drop).

Green Building in the Trump Era

Posted on December 9, 2016 by Martin Holladay

Most green building advocates are concerned about global climate change. So what are we to make of the election of Donald Trump?

Well, there is bad news and good news.

The bad news is that Trump is ignorant about basic economic facts relevant to the energy industry and is disdainful of scientific consensus. There’s more bad news:

  • Trump believes that climate change is a hoax;
  • Trump has promised to withdraw from (or, as he puts it, to “cancel”) the Paris Climate Agreement;
  • Trump has ridiculed supporters of renewable energy;
  • Worries About Trapping Moisture

    Posted on December 2, 2016 by Martin Holladay

    A significant number of questions posted by readers on the site are variations of, “Will this wall detail (or roof detail) trap moisture?”

    When I entered “trap moisture” into the GBA search box, I got 182 results. The search terms “trapping moisture” yielded another 104 results. Clearly, there is a high level of concern around the issue.

    Cold Floors and Warm Ceilings

    Posted on November 25, 2016 by Martin Holladay

    During the winter, the air near your floor is cold, while the air near your ceiling is hot. Similarly, during the summer, the air conditioner keeps your first floor comfortable, while the rooms on the second floor are unbearably hot. What’s going on?

    The usual answer is, “Heat rises.” But that explanation isn’t quite accurate. (It’s true that hot air rises by convection. But heat travels in all directions, including sideways and downward, by conductionMovement of heat through a material as kinetic energy is transferred from molecule to molecule; the handle of an iron skillet on the stove gets hot due to heat conduction. R-value is a measure of resistance to conductive heat flow. and radiation.)

    Drywall Finishing Tips for Owner-Builders

    Posted on November 18, 2016 by Martin Holladay

    Plenty of owner-builders are happy to hang drywall. When it comes to taping and finishing, however, most feel less confident. Some just shrug their shoulders and announce, “I’m going to hire a contractor to do the drywall.”

    Spreading drywall mud is like frosting a cake. You need to have the right touch, and the right touch takes experience. The first time you frost a cake, you’re going to damage the surface of the cake and get cake crumbs mixed with the frosting. You need to take a deep breath, slow down, and adjust the pressure on your knife.

    All About Doors

    Posted on November 11, 2016 by Martin Holladay

    Almost every house has at least two exterior doors. A bad exterior door is ugly, leaky, made from materials that injure the planet, and has a low R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. . A good door is attractive, doesn’t leak air, is manufactured with materials that are harvested or produced in a sustainable way, and has a decent R-value.

    Drainwater Heat Recovery Can Lower Your HERS Score

    Posted on November 4, 2016 by Martin Holladay

    Drainwater heat recovery (DHR) devices have been around for more than twenty years. By now, over 60,000 of the units have been installed in North America. When one of these devices is installed in a typical single-family home, it can reduce the amount of energy used for domestic hot water by 15% to 22%.

    States are Amending, then Adopting, the 2015 IECC

    Posted on October 28, 2016 by Martin Holladay

    In the U.S., the system for writing, adopting, and enforcing building codes is peculiar. Lots of people are confused about building codes.

    Anyone interested in understanding building codes in the U.S. needs to start by learning a few basic facts:

    • The U.S. doesn’t have a national building code. Building codes vary from state to state, and in some cases from city to city.

    Ventilation Failures and Vocabulary Lessons

    Posted on October 21, 2016 by Martin Holladay

    During the last week of September, I attended the annual conference sponsored by the Energy and Environmental Building Alliance (EEBA). This year’s conference was held in Frisco, Texas.

    EEBA was founded in Minnesota in 1982; the original name of the organization was the Energy Efficient Building Association. Thirty-four years later, EEBA is still going strong.

    A Superinsulated House from 1984

    Posted on October 14, 2016 by Martin Holladay

    Were the techniques of superinsulation well understood in the early 1980s? The answer depends on who you talk to. Back then, in most areas of the country, residential builders were slapping together leaky homes insulated with thin fiberglass batts. Yet even 35 years ago, a small subset of builders had already adopted superinsulation techniques. In the early 1980s, anyone who was interested in the topic had access to in-depth information on superinsulation details.

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