The most recent blogs at Green Building Advisor

Three Types of Heating and Cooling Loads

Posted on January 14, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

What is it about the number three? You've got the Three Musketeers, the Three Little Pigs, and the Three Stooges. Then there's three strikes (what every pitcher wants), three branches of government (executive, legislative, and judicial), and the three kinds of people (those who can do math and those who can't). And let's not forget three on a match, three wise men, and threepeats.

Today we'll look at another big three: the three types of heating and cooling loads. Do you know what they are already?

An Off-Grid Solar Community

Posted on January 12, 2015 by Ajahn Sona in Guest Blogs

Birken Forest Monastery is a retreat center in the mountains of British Columbia. It's located at an elevation of 4,000 feet at Latitude 51, and experiences about 9,000 heating degree days (Fahrenheit) per year. The buildings are about 15 years old.

We are off the grid. The nearest electricity line is 4 miles away, and it would cost about $200,000 to bring grid power in. (Then, of course, we would still have to pay for the electricity.) So off-grid it is, and will remain.

Building a Foam-Free House

Posted on January 9, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Many green builders want to build a foam-free house — that is, a house without any rigid foam insulation or spray foam insulation.

How Replacing a Furnace Can Make You Less Comfortable

Posted on January 7, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Let's say your trusty old furnace is at the end of its life. You've got to buy a new one, so you call your HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. company and they rush over to make sure you don't freeze during the next cold snap. They go and take a look at your furnace and find its capacity. They come back and tell you that you have a furnace rated for 60,000 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. per hour and then talk to you about some of the options.

Interior Paint and a Back Porch for the Potwine Passivhaus

Posted on January 6, 2015 by Alexi Arango in Guest Blogs

As they set out to build a single-family PassivhausA 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. on Potwine Lane in Amherst, Massachusetts, Alexi Arango and LeeAnn Kim asked themselves, “Is it possible to live without burning fossil fuels?” One measure of success would be meeting their goal of 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. performance. This is the twelfth blog in a series.

Choosing a New Wood Stove

Posted on January 5, 2015 by Scott Gibson in Q&A Spotlight

Patricia Appelbaum is in the market for a new wood-burning stove, one without a catalytic element, to provide mostly supplemental heat for her 1,600-square-foot home. There are a lot of models to choose from, and that's part of the problem.

Redefining Passivhaus

Posted on January 2, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

In January 2012, 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), announced that her organization would develop a new passive house standard for North America — a standard that differed from the Passivhaus standard developed in Darmstadt, Germany.

The Potwine Passivhaus Gets Insulation and Drywall

Posted on December 30, 2014 by Alexi Arango in Guest Blogs

As they set out to build a single-family PassivhausA 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. on Potwine Lane in Amherst, Massachusetts, Alexi Arango and LeeAnn Kim asked themselves, “Is it possible to live without burning fossil fuels?” One measure of success would be meeting their goal of 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. performance. This is the eleventh blog in a series.

Passive House is Looking for a Few Good Men (and Women)

Posted on December 29, 2014 by Carl Seville, GBA Advisor in Green Building Curmudgeon

I make no claim to being an expert on 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., but ignorance has never stopped me from expressing my opinion before. Among the major complaints about the Passive House standard is that it has inflexible energy use requirements, and the European-designed program does not effectively address the wide range of U.S. climate zones. This inflexibility often leads those who pursue this certification to install enormous quantities of insulation, particularly under slabs, which raises a variety of questions and concerns about the usefulness of this practice.

Solar Thermal Is Really, Really Dead

Posted on December 26, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Back in early 2012, in an article called “Solar Thermal Is Dead,” I announced that “it’s now cheaper to heat water with a 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. array than solar thermal collectors.”

Now that almost three years have passed, it’s worth revisiting the topic. In the years since that article was written, the cost to install a photovoltaic (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.) system has dropped significantly. Moreover, I’ve come across monitoring data that allow for a more accurate estimate of the amount of electricity needed to heat water with electric resistance elements or a heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump..

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