The most recent blogs at Green Building Advisor

Walls and Windows for the Orenco Passivhaus

Posted on July 23, 2015 by Mike Steffen in Guest Blogs

This is Part 3 of a blog series describing construction of the Orchards at Orenco project in Oregon. The first installment was titled The Largest Passivhaus Building in the U.S.

How Much Will Shading Your Air Conditioner Improve Its Efficiency?

Posted on July 22, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

I got a question this weekend that's often asked — and, I'm sure, wondered about — by homeowners: "Will my household AC system run more efficiently (perhaps cycle on/off fewer times, or the compressor won't have to run as long when it cycles on) by shading the compressor?"

I've written about the outdoor unit of air conditioners and heat pumps a few times, but I've never tackled this question directly. Let's change that now.

An Inside Look at the New PHIUS Standard

Posted on July 21, 2015 by Katrin Klingenberg in Guest Blogs

Since 2012, 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. Institute U.S. has worked on delivering a standard that would make it easier and more practical for professionals to deliver ambitious, performance-based, energy-efficient designs. PHIUS also sought to make a standard that would be useful in wider policy proposals.

In the process, PHIUS addressed climate-specific and economic issues that had surfaced while applying the European Passivhaus criteria to buildings across North America’s varied climate zones.

Why Are Houses Built This Way?

Posted on July 20, 2015 by Scott Gibson in Q&A Spotlight

Readers of GreenBuildingAdvisor's Q&A forum, and the bi-monthly Q&A Spotlights, are probably used to thorough parsings of seemingly small details in high-performance construction. But GBAGreenBuildingAdvisor.com reader Peter L. brings our attention to an elemental question: Are we still in the dark ages of residential building?

Saving Energy With an Evaporative Cooler

Posted on July 17, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Evaporative coolers are appliances used to cool indoor air. Evaporative coolers use much less energy than air conditioners, but they can’t cool indoor air effectively in all weather conditions.

Ventilation Doesn’t Happen in a Vacuum

Posted on July 16, 2015 by Reid Baldwin in Guest Blogs

Forced ventilation is about exchanging indoor air for outdoor air, which can be accomplished by pulling air in (supply ventilation), pushing air out (exhaust ventilation) or both (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). ). It is well known that these forced ventilation options impact which air gets exchanged, but each type should result in the same amount of additional air exchange, right?

Could a Bare-Bones Energy Code Work?

Posted on July 15, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Energy codes have all kinds of requirements. You have to have certain R-values in walls, floors, and ceilings. Your windows have to have the right U-values and solar heat gainIncrease in the amount of heat in a space, including heat transferred from outside (in the form of solar radiation) and heat generated within by people, lights, mechanical systems, and other sources. See heat loss. coefficients. The infiltration rate and duct leakage have to be measured and come in below a threshold for your climate zone. And then there are the different pathways for compliance: prescriptive, UA tradeoffs, performance, or HERS Index.

EPA Looks at Fracking Risks to Water

Posted on July 14, 2015 by Mark Brownstein in Guest Blogs

The Environmental Protection Agency (EPA) recently released its long-awaited draft report on impacts associated with hydraulic fracturing on drinking water, completing the most extensive scientific review of published data to date.

Windows and Floors at a Pretty Good House in Maine

Posted on July 13, 2015 by stephen sheehy in Guest Blogs

This is Part 5 of a blog series describing the construction of Stephen Sheehy’s house in Maine. The first installment was titled Pretty Good, Not So Big Maine House.

Installing Windows In a Foam-Sheathed Wall

Posted on July 10, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Every now and then, a GBAGreenBuildingAdvisor.com reader posts the question, “How do you install windows in a wall with exterior rigid foam?”

The answer to the question is surprisingly complicated. The best method will depend on several factors, including the answers to these questions:

  • Are the windows innies or outies?
  • What type of water-resistive barrierSometimes also called the weather-resistive barrier, this layer of any wall assembly is the material interior to the wall cladding that forms a secondary drainage plane for liquid water that makes it past the cladding. This layer can be building paper, housewrap, or even a fluid-applied material. (WRB) does the wall have: Zip 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. , housewrap, or rigid foam?
  • How thick is the rigid foam? (For more information on this question, see Calculating the Minimum Thickness of Rigid Foam Sheathing.)
Register for a free account and join the conversation


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