The most recent blogs at Green Building Advisor

How to Install Rigid Foam On Top of Roof Sheathing

Posted on April 3, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

A roof over a vented, unconditioned attic does not need to include any insulation. However, most cathedral ceilings and low-slope (flat) roofs are insulated roof assemblies: with this kind of roof, the insulation follows the slope of the roof.

Insulated roof assemblies can be vented or unvented. There are lots of different ways to insulate this type of roof, but one of the best methods calls for the installation of rigid foam insulation above the roof sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. .

Lawns Gone Wild

Posted on April 2, 2015 by Lance Hosey in Guest Blogs

Because environmental challenges are so complicated, potential solutions are rarely as simple as they seem.

For example, the market for electric vehicles (EVs) is growing rapidly, outpacing hybrids, although the supply is nowhere near the million EVs that President Obama called for in his 2011 State of the Union address (which might be why he didn't mention the topic this year).

California’s Mistake Puts Spray Foam Insulation on the Bad List

Posted on April 1, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Last summer I learned about the state of California's efforts to create more healthful buildings and working conditions. In 2008, they passed the California Green Chemistry Initiative with the intent of reducing state residents' exposure to toxic chemicals.

Breathe Easy With Balanced Ventilation

Posted on March 31, 2015 by Sean Groom in Green Building Blog

Houses need fresh air. Without ventilation, the quality of indoor air can rapidly become worse than that of the outside air; that holds true even in urban areas. Common contaminants include gases, odors, and moisture, and these can stem from utility rooms, garages, basements, bathrooms, and kitchens.

Reflections on BuildingEnergy 2015

Posted on March 31, 2015 by Marc Rosenbaum in Guest Blogs

For 36 years, my professional community has been the Northeast Sustainable Energy Association (NESEANorth East Sustainable Energy Association. A regional membership organization promoting sustainable energy solutions. NESEA is committed to advancing three core elements: sustainable solutions, proven results and cutting-edge development in the field. States included in this region stretch from Maine to Maryland. www.nesea.org). In early March we gathered once again in Boston for the BuildingEnergy conference. It was one of the best ever.

I go to BuildingEnergy to get my mind twisted out of my ordinary fixed ideas and to learn new ways to think. This year was a bumper crop.

How Would You Insulate My New House?

Posted on March 30, 2015 by Scott Gibson in Q&A Spotlight

Nik Fiorito is grappling with the same issues every owner/builder eventually confronts: What's the best way of insulating a new house? Only in Fiorito's case, it gets a little more complicated.

First, he's building in Climate Zone 7, forty minutes north of the U.S.-Canadian border, on a hilltop where the temperature averaged 3 below zero F (-19.6 degrees C.) this past February. He's also considering a fully off-grid 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.) system plus 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. for both heat and domestic hot water.

Exploiting the Elements of Passive Design

Posted on March 30, 2015 by James Tuer in Green Building Blog

Every site has a story to tell, and the right house can help to tell that story. Located on the western coast of Bowen Island in British Columbia, this house is a good example. My clients, a professor of East Asian archaeology and a researcher from Kyoto, Japan, had worked the land for years, cultivating extensive gardens of ornamental plants from around the world. When they approached me to design a house for the property, they had only two requests: The home must fit the site, and it should have minimal impact on the landscape. The rest of the design was left in my hands.

Walls With Interior Rigid Foam

Posted on March 27, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

There are two main ways of reducing thermal bridgingHeat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall, because of thermal bridging through the steel. through studs: you can build a double-stud wallConstruction system in which two layers of studs are used to provide a thicker-than-normal wall system so that a lot of insulation can be installed; the two walls are often separated by several inches to reduce thermal bridging through the studs and to provide additional space for insulation., or you can install a continuous layer of rigid insulation on one side of the wall.

Most builders who install a continuous layer of rigid insulation use rigid foam (polyisocyanurate, expanded polystyrene, or extruded polystyrene); a small minority of builders use semi-rigid panels of mineral wool.

Builders who install rigid foam on the walls of a new building usually install the foam on the exterior side of the wall. There are several reasons for this:

Insulating With Damp-Spray Cellulose

Posted on March 26, 2015 by Leroy Anthony in Green Building Blog

Insulating any building can be a challenge, but the nonprofit energy-efficiency and weatherization company I work for, Community Environmental Center, frequently insulates old houses being rebuilt for residential group homes and elderly housing in New York City. These skilled-care buildings, like the one shown in these photos, are crammed with pipes, ducts, and wires, so they’re tough to insulate. They’re also located in dense urban neighborhoods that can be busy and loud.

Water Heaters Get an Efficiency Makeover

Posted on March 26, 2015 by Marianne DiMascio in Guest Blogs

From the rustic 1850s pump shower to the 1920s Humphrey automatic to today’s modern units, water heaters have made great strides in performance and efficiency. On April 16, water heaters will take the next great stride when manufacturers must comply with new Department of Energy (DOEUnited States Department of Energy.) efficiency standards.

The most common water heaters manufactured on and after this date will get a modest boost in efficiency, while units over 55 gallons will shift to next-generation technology, cutting utility bills by one-fourth to one-half depending on the technology.

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