The most recent blogs at Green Building Advisor

Greenbuild Expo 2010 Recap

Posted on November 24, 2010 by Carl Seville, GBA Advisor in Green Building Curmudgeon

Another Greenbuild Expo is in the books, and based on the Twitter traffic (hashtag #greenbuild), people can’t stop talking about it, so I suppose it’s my turn to chime in. According to the USGBC, attendance was up slightly from last year. The show floor was huge, as always, although the arrangement did not feel crowded or even that big to traverse.

Does Spot Ventilation Work in an Ultra-Tight House?

Posted on November 22, 2010 by Scott Gibson in Q&A Spotlight

UPDATED: 12/9/10 with expert opinions from David White and Marc Rosenbaum

Frank O's new house is tight — very tight. Tests by an energy auditor measured 0.13 air changes per hour at 50 pascals of depressurizationSituation that occurs within a house when the indoor air pressure is lower than that outdoors. Exhaust fans, including bath and kitchen fans, or a clothes dryer can cause depressurization, and it may in turn cause back drafting as well as increased levels of radon within the home. (ACH50), meaning the house beats the very stringent airtightness target of the 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. standard.

Frank O has installed 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. ) to provide fresh air as well as fans for spot ventilation and a range hood fan rated at 189 cubic feet per minute (cfm).

Sounds perfect. So what's the problem?

Makeup Air for Range Hoods

Posted on November 19, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Most homes have several exhaust appliances. These typically include a bathroom fan (40-200 cfm), a clothes dryer (100-225 cfm), and perhaps a power-vented water heater (50 cfm), a wood stove (30-50 cfm), or a central vacuum cleaning system (100-200 cfm). But the most powerful exhaust appliance in most homes is the kitchen range-hood fan (100-1,200 cfm).

Green Building Priority #1 – Reduce Energy Use

Posted on November 17, 2010 by Alex Wilson in Energy Solutions

Energy consumption carries with it numerous environment impacts. Most importantly, burning fossil fuels (coal, natural gas, to oil) to heat homes or generate electricity emits the greenhouse gas carbon dioxide, which is the leading cause of global climate change. Debate about whether climate change is real has long since ended in most scientific circles and is now relegated to the radical blogosphere and pseudo news outlets. The vast preponderance of evidence supports the contention that greenhouse gases being emitted into the atmosphere are trapping heat and warming the globe.

Will Certified Green Homes Ever Serve Middle America?

Posted on November 17, 2010 by Michael Strong, LEED Associate, CGP in Business Advisor

Custom high-performance certified green homes? Been there, done that.

Ground-Source Heat Pumps, Part 2: Rules of Thumb

Posted on November 16, 2010 by Christopher Briley in Green Architects' Lounge

In Part One of this episode from the Green Architects' Lounge, we only scratched the surface. Now it's time to really dig in and decide if 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. system is right for you, and if so, to start planning for it.

In Part Two of the podcast, we discuss:

  • A tale of two houses: Chris shares a story of two houses—one a success, and one that had to abandon using a ground-source heat pump
  • Rule of thumb for flow: 3 gal. per minute per ton of heating/cooling
  • Integrated Pest Management: Get to Know Mike Potter and Bill Quarles

    Posted on November 15, 2010 by Peter Yost in Green Communities

    Each word in the phrase “integrated pest management” (IPM) is important. It means a thoughtful, systems-approach to mediate contact between people and unwanted critters—bugs, usually, but sometimes small mammals as well. We call them pests, but we really don’t care if they do their job within an ecosystem; we just don’t want them in our homes or on us.

    IPM during construction

    How to Finish Exterior Foundation Insulation

    Posted on November 15, 2010 by Scott Gibson in Q&A Spotlight

    Energy gurus and building codes routinely recommend these days that foundation walls be insulated. One way of accomplishing that is by adding a layer of rigid foam insulation on the outside of the foundation.

    And that's exactly what William Poole is planning to do.

    Most of the rigid foam insulation will be underground and out of sight. But what do you do with that stretch of exposed insulation above grade?

    To Install Stucco Right, Include an Air Gap

    Posted on November 12, 2010 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

    In many areas of the country, hundreds of stucco-clad homes have suffered wall rot. Although building scientists are still researching the causes of wall rot behind stucco, it’s clear that all of these walls got wet and were unable to dry.

    The Green Countertop Dilemma

    Posted on November 11, 2010 by Ann Edminster, GBA Advisor in Green Building Blog

    During a recent visit to Eco6Design in Half Moon Bay, California, I was drooling over all the fabulous “eco” options for countertops. Serious eye candy! Vetrazzo, Fireclay Tile, Stone Age, IceStone, Fuez. I was itching to go home, rip out my pale-avocado-tile-with-black-grout counters and start afresh.

    Register for a free account and join the conversation


    Get a free account and join the conversation!
    Become a GBA PRO!