Musings of an Energy Nerd

Just Two Minisplits Heat and Cool the Whole House

Posted on August 17, 2012 by Martin Holladay, GBA Advisor

Carter Scott was one of the first builders bold enough to build a cold-climate home heated by only two ductless minisplit units (one in the downstairs living room, and one in the upstairs hallway). Skeptics predicted that the unheated bedrooms would be cold and uncomfortable. Yet Scott was confident that the home’s excellent thermal envelope — with high-R walls, triple-glazed windows, and low levels of air leakage — would keep the homeowners comfortable even when the bedroom doors were closed.

Living Without Electricity Bills

Posted on August 10, 2012 by Martin Holladay, GBA Advisor

Chuck Reiss, a builder in northwest Vermont, had a bold plan in 2007: he wanted to build a cluster of six superinsulated homes on a 24-arce site in Hinesburg. Reiss planned to install a roof-mounted 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. array on each house, with the goal of making the homes net-zero energyProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines., or close to it.

A New Passivhaus Standard for North America

Posted on August 3, 2012 by Martin Holladay, GBA Advisor

Katrin Klingenberg, the founder of the Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. Institute U.S. (PHIUS), caused a minor earthquake earlier this year when she suggested that the existing Passivhaus standard didn’t make sense in North America.

Do Foil-Faced Building Products Block Cell Phone Reception?

Posted on July 27, 2012 by Martin Holladay, GBA Advisor

It’s increasingly common for builders to install rigid foam on exterior walls and roofs. And among green builders, polyisocyanurate foam — a type of foam that often comes with foil facing — is generally perceived as the most environmentally friendly foam available.

Alaskan Glaciers Are Rapidly Melting

Posted on July 20, 2012 by Martin Holladay, GBA Advisor

I recently returned from a two-week family vacation trip to Alaska. This was my first trip to Alaska; of course, two weeks is a very brief time to visit such a vast state. We were able to spend some time in Fairbanks, Denali National Park, Anchorage, and Seward. We also spent several days fishing along the Salcha River and at Lower Paradise Lake on the Kenai Peninsula.

The Connection Between Obesity and Climate Change

Posted on July 13, 2012 by Martin Holladay, GBA Advisor

Positive feedback loops that reinforce global warming are scary. Here’s an example of such a feedback loop: warmer temperatures melt Arctic sea ice earlier in the spring and reduce the size of the summer ice pack. Since the dark ocean has less reflectance than ice, a smaller ice pack means that more solar radiation is absorbed by the ocean every summer, further warming the planet.

New Green Building Products — July 2012

Posted on July 6, 2012 by Martin Holladay, GBA Advisor

Once again, the “in” box on my desk is beginning to fill up with a stack of brochures describing interesting new products.

I've selected four products to review in this latest roundup: an insert panel to improve the thermal performance of insulated concrete forms (ICFs); a new wall system for manufactured stone veneer; and two new water-resistive barriers (WRBs).

How to Insulate a Basement Wall

Posted on June 29, 2012 by Martin Holladay, GBA Advisor

Here at GBAGreenBuildingAdvisor.com, we regularly receive questions from readers about the best way to insulate a basement wall. Since these questions pop up frequently, it’s time to pull together as much information as possible on this topic.

In this article, I’ll try to explain everything you always wanted to know about insulating basement walls.

Understanding Energy Units

Posted on June 22, 2012 by Martin Holladay, GBA Advisor

If you’ve ever been confused by the difference between 500 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. and 500 Btu/h, you probably can use a handy cheat sheet to explain energy units. As a guide through the thorny thickets of energy, power, and the units used to measure them, I’ve assembled some questions and attempted to answer them.

Joe Lstiburek Discusses Basement Insulation and Vapor Retarders

Posted on June 15, 2012 by Martin Holladay, GBA Advisor

Dr. Joseph Lstiburek needs little introduction. The well-known Canadian engineer is a principal of the Building Science Corporation in Massachusetts. He’s also a regular GBA podcaster and Fine Homebuilding author.

On Wednesday, June 6th, I attended an all-day building science class presented by Dr. Joe in Westford, Massachusetts. As usual, his presentation combined salty language, corny jokes, light-hearted insults, and rock-solid building science information.

Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!

Syndicate content