The most recent blogs at Green Building Advisor

A Passivhaus Conference in Germany

Posted on May 13, 2014 by Ken Levenson in Guest Blogs

The 2014 International 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. Conference was held in Aachen, Germany, on April 25-26. Produced by the Passivhaus Institut (PHI), this annual conference offered a dizzying and inspiring array of information and networking opportunities.

A Green Building Conference in Montreal

Posted on May 9, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Although I live in the middle of nowhere, in the woods of the Northeast Kingdom of Vermont, my house is only a two-and-a-half-hour drive from the cosmopolitan city of Montreal, Quebec. A few weeks ago I made the drive north to meet a few green builders from Quebec and to attend a green building conference called Ecohabitation 2014.

Montreal is a fun city where it's easy to buy a decent baguette. The city also offers the chance to sample delicious food prepared by Quebecois born in Lebanon, Tunisia, Mexico, India, and many other countries.

Resilience as a Driver of Change

Posted on May 7, 2014 by Alex Wilson in Energy Solutions

Readers of this column have heard me argue in the past that resilience can be a motivation for taking actions that will not only make us and our families safer, but also help to mitigate climate change. Let me lay out that basic argument again.

The Great Ventilation Debate, Live at the ACI Conference

Posted on May 6, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Last week at the Affordable Comfort Conference (also known as ACI), I co-moderated a panel called The Great Ventilation Standard Debate.1 Duncan Prahl of Ibacos proposed the session and rounded up a collection of some of best building science folks in North America to be on the panel.

Do I Really Need a Concrete Basement Floor?

Posted on May 5, 2014 by Scott Gibson in Q&A Spotlight

Rob Rosen is diving into a basement remodel, a job that involves digging out and removing a concrete slab to provide more headroom so the basement can be turned into usable living space.

He'll reinforce the footing and foundation as needed, but when it comes time to build a new floor for the basement, Rosen wonders whether he can go with something other than a concrete slab.

WUFI Is Driving Me Crazy

Posted on May 2, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Is it possible to describe all of the factors that influence heat and moisture movement through a wall during a single day? Perhaps. We could start by listing the outdoor conditions, including air temperature, relative humidity, wind speed, wind direction, the angle of the sun with respect to the wall (its altitude and azimuth), the cloud thickness, the precipitation rate, and the depth of snow on the ground. Needless to say, many of these factors change from minute to minute.

Taking Action on Climate Change

Posted on May 1, 2014 by Alex Wilson in Energy Solutions

In my previous blog I described the international effort to understand climate change. The United Nations’ IPCC is leading the charge, and efforts like the Kyoto Treaty have grown out of that background work. But are we getting closer to solving the problem?

What Happens When You Put a Plastic Vapor Barrier in Your Wall?

Posted on April 30, 2014 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

A lot of people have heard advice about vapor barriers and vapor retarders. Many of them have walked away confused. A big part of the problem, I think, is that they've been told what to do — "Put it on the warm-in-winter side," or "Never use one" — but they haven't had the physics of what happens explained to them.

Moving to a New House

Posted on April 29, 2014 by Marc Rosenbaum in Guest Blogs

Jill and I got hitched on June 2, 2013, on the beach at the Gay Head Cliffs on Martha's Vineyard. We then spent the next 7 1/2 days packing up our possessions at our old house at Island CohousingDevelopment pattern in which multiple (typically 8 to 30) privately owned houses or housing units are clustered together with some commonly owned spaces, such as a common workshop, greenhouse, etc. Automobiles are typically kept to the perimeter of the community, creating a protected area within where children can play. Usually, residents are closely involved in all aspects of the development, from site selection to financing and design. in preparation to moving to our new place. We closed on the old house on June 10th. Not a recommended honeymoon.

Does a Home with an HRV Also Need Bath Fans?

Posted on April 25, 2014 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

A balanced ventilationMechanical ventilation system in which separate, balanced fans exhaust stale indoor air and bring in fresh outdoor air in equal amounts; often includes heat recovery or heat and moisture recovery (see heat-recovery ventilator and energy-recovery ventilator). system — for example, a system with 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.) — exhausts stale air from some rooms in a building, while simultaneously introducing fresh outdoor air to other rooms. The best balanced ventilation systems use dedicated ventilation ductwork. Usually, these systems pull exhaust air from damp, smelly rooms — bathrooms and laundry rooms — and introduce fresh air to the rooms where people spend most of their time — bedrooms and the living room.

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