The most recent blogs at Green Building Advisor

Drainwater Heat Recovery Can Lower Your HERS Score

Posted on November 4, 2016 by user-756436 in Musings of an Energy Nerd

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%.

Savings from Building Energy Codes Are a Big Deal

Posted on November 3, 2016 by Anonymous in Guest Blogs

By LAUREN URBANEK

How much energy do building codes save over time? That’s the question that a new report released last week from the Department of Energy (DOEUnited States Department of Energy.) aims to answer — and the answers show the results can be mammoth, both in terms of consumers' utility bill savings and avoided carbon emissions.

Landfills Have a Huge Greenhouse Gas Problem

Posted on November 2, 2016 by EricaGies in Guest Blogs

We take out our trash and feel lighter and cleaner. But at the landfill, the food and yard waste that trash contains is decomposing and releasing methane, a greenhouse gas that’s 28 times more potent than carbon dioxide. Landfill gas also contributes to smog, worsening health problems like asthma.

Can an Urban River Be Restored?

Posted on November 1, 2016 by Anonymous in Guest Blogs

By JIM ROBBINS

In its natural state, before it was channeled and lined with concrete, the 51-mile-long Los Angeles River was often little more than a trickle for nine months of the year. During the rainy season, however, the small braided stream would turn into a powerful, churning river. It behaved like a dropped firehose, wildly lashing the Los Angeles valley, scouring gravel and soil across a seven-mile-wide floodplain, and carving a new course with every deluge. When the waters receded, a mosaic of fertile marshes, ponds, and other wetlands remained.

Wolfe Island Passive: Windows, Doors, and Utilities

Posted on October 31, 2016 by DMWood in Guest Blogs

Editor's note: David and Kayo Murakami Wood are building what they hope will be Ontario's first certified 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. on Wolfe Island, the largest of the Thousand Islands on the St. Lawrence River. They are documenting their work at their blog, Wolfe Island Passive House. For a list of earlier posts in this series, see the sidebar below.

States are Amending, then Adopting, the 2015 IECC

Posted on October 28, 2016 by user-756436 in Musings of an Energy Nerd

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.

Off-Grid in Canada: Architecture and Interior Design

Posted on October 27, 2016 by Craig_Anderson in Guest Blogs

This is the last in a series of posts by Craig Anderson describing the off-the-grid house he built with his wife France-Pascale Ménard near Low, Québec. Craig writes about the "Seven Hills Project" in a blog called Sunshine Saved. For a list of Craig's previous posts, see the list of "Blogs by Craig Anderson" in the sidebar below.

High Humidity in Spray Foam Attics

Posted on October 26, 2016 by ab3 in Building Science

I recently investigated an attic with spray foam insulation where we observed an interesting humidity pattern. We placed data loggers near the ridge and floor of the attic as well as in the living space and outdoors.

The graph at below shows dew point data for the four locations. The really interesting part is the big difference in dew point between the highest and lowest points in the attic, shown by the red and green curves in the graph.

Junk Science and the Heat-Island Effect

Posted on October 25, 2016 by StuartKaplow in Guest Blogs

Among the most interesting exhibitors at the GreenBuild International Conference and Expo, an event held in early October in Los Angeles, may have been the Asphalt Pavement Alliance, a group that challenged what we thought we knew about the urban heat-island effect with peer-reviewed research from Arizona State University (ASU).

Is a Ground-Source Heat Pump the Right Choice?

Posted on October 24, 2016 by ScottG in Q&A Spotlight

Ben Rush likes the idea of a ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures., despite their reputation for higher cost than other heating and cooling alternatives.

A ground-source heat pump (GSHPs) requires heat-exchange tubing buried in the ground or inserted in a well or pond. The excavation required to bury the lines (or drill an extra well or two) helps to make GSHPs more expensive than air-source units. In addition, the equipment itself tends to be more costly. In all, GSHPs suffer a significant disadvantage when it comes to cost.

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