The most recent blogs at Green Building Advisor


Posted on January 22, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

After investigating various ventilation options, many residential designers conclude that they want either a heat-recovery ventilator (HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. ) or an energy-recovery ventilator (ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV.). They often remain confused, however, about which of the two devices to choose.

Every tight home needs a mechanical ventilation system.

Does Building Green Cost More?

Posted on January 21, 2010 by Daniel Morrison in Green Building Blog

As you know, I posted a survey the other day asking for feedback from folks who use Green Building Advisor. At the end of the survey I asked a couple of open-ended questions in order to get some comments. While not nearly enough of you have filled out the survey (if you don't vote, you can't complain), a couple of good comments came in. Thanks for filling out the survey and sharing your thoughts with us.

One comment, I think, can make a good conversation starter.

Can a Kitchen Downdraft Fan Be Connected To an HRV?

Posted on January 21, 2010 by Daniel Morrison in Q&A Spotlight

Powerful kitchen exhaust fans do a good job of removing cooking odors and smoke. They also have the potential to depressurize a house, causing water heaters to backdraft and pulling ashes out of the fireplace and onto the hearth.

Help Us Get Better

Posted on January 20, 2010 by Daniel Morrison in Green Building Blog

Today we're one year old!

Thanks to all of you who have registered for Green Building Advisor, and to those who have signed up for PRO membership — thanks for paying our salaries.

To help us better understand who you are, what you want, and how we can help you more effectively, please take a few minutes to fill out this short survey.

The link takes you to, a web-based survey service, so don't be alarmed that you're leaving Green Building Advisor.

Thank you very much for your help,

Innovative Financing for Energy Improvements

Posted on January 19, 2010 by Alex Wilson in Energy Solutions

One of the greatest challenges to energy improvements is the financing needed to make those improvements. Conventional home improvement and business loans have such short terms (usually less than ten years) that the interest costs are often greater than the energy savings—making such loans hard to afford for most families and businesses. Also, it’s hard to justify putting money into a house if you’re not sure how long you’ll be there.

GREEN BUILDING TIP: Design for Efficient Lighting

Posted on January 18, 2010 by Daniel Morrison in Green Building Blog

A mix of lighting sources allows you to use the type of light you need: task lighting for reading, food preparation and other activities — where strong, concentrated light is helpful — or ambient lighting where more general illumination is better. Not all lights have to be on all the time, and natural light can be a significant contributor when floor plans are designed accordingly.

Steve’s Garage

Posted on January 17, 2010 by michael maines in Building Science

Once a month in Portland, Maine, a group of builders, carpenters, architects, engineers, energy auditors, insulation contractors, and other fans of building science get together for, to quote the invitation, “an informal discussion for building professionals to ask, learn, debate, knock around, support, agonize over, ridicule, flog and answer the challenges and concepts of the best building practices.”

Home Dashboards Help to Reduce Energy Use

Posted on January 15, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

In recent years, the technology of our cars has advanced at a more rapid rate than the technology of our homes. A new car’s dashboard has gauges that display all kinds of information, including the amount of fuel in the car’s tank, the oil pressure, the electrical system voltage, and sometimes the tire pressure. Many new cars even have a real-time fuel-efficiency gauge that displays miles per gallon.

When Will We Reach Beautiful Simplicity in Green Building?

Posted on January 15, 2010 by Carl Seville, GBA Advisor in Green Building Curmudgeon

Sometimes the complexity of building science makes me a little crazy. The worst manifestation of this is when I make recommendations to clients or building pros at meetings or in seminars. Rarely is there a single, clear-cut solution to most problems. “It depends” is usually the right answer. It depends on the climate. It depends on the materials used. It depends on existing conditions. It depends on so many things that the average person slips quickly into MEGO mode (My Eyes Glaze Over).

Can Spray Foam Rot Your Roof?

Posted on January 14, 2010 by Daniel Morrison in Q&A Spotlight

Ice dams are a familiar problem in New England and other parts of the country where winters are long and cold. Snow on under-insulated and under-ventilated roofs melts, pools and refreezes to form a dam. Water backs up under the shingles and much to the horror of homeowners often finds its way inside the building.

Spray foam polyurethane insulation is supposed to be a hedge against that problem. By forming an effective seal around rafters, and offering respectable R-values, foam should be blocking the migration of cold air into the roof where it can condense into water.

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