The most recent blogs at Green Building Advisor

Wolfe Island Passive: Heat Recovery Ventilation

Posted on March 27, 2017 by David Murakami Wood in Green Building Blog

Editor's note: David and Kayo Murakami Wood are building what they hope will be Ontario's first certified 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. on Wolfe Island, the largest of the Thousand Islands on the St. Lawrence River. They are documenting their work at their blog, Wolfe Island Passive House. For a list of earlier posts in this series, see the sidebar below.

Who Can Perform My Load Calculations?

Posted on March 24, 2017 by Martin Holladay in Musings of an Energy Nerd

To design a residential heating or cooling system, the first step is to perform a load calculation. (A load calculation determines the size of a building’s heating loadRate at which heat must be added to a space to maintain a desired temperature. See cooling load. on one of the coldest nights of the year and the size of a building’s cooling load on one of the hottest afternoons of the year.) It’s important to know the size of these loads to determine the size of the required heating and cooling equipment.

Choosing and Installing Windows in the ProHOME

Posted on March 23, 2017 by Mike Guertin in Guest Blogs

Editor's note: This post originally was published as part of the ProHOME series at Fine Homebuilding magazine. Sean Groom, a former editor at FHB, leads it off with a discussion of how these windows were chosen, and FHB editorial advisor and builder Mike Guertin picks it up with instructions on how to install the windows correctly.

Is There Lead in the Water of Your Green Building?

Posted on March 22, 2017 by Stuart Kaplow in Guest Blogs

Worries about lead leaching from pipes and faucets into drinking water are not new. But the broad growth of "green" buildings, including schools, that use water conservation strategies has the potential to lower the quality of drinking water in their plumbing systems.

To reduce water consumption, the latest version of LEEDLeadership in Energy and Environmental Design. LEED for Homes is the residential green building program from the United States Green Building Council (USGBC). While this program is primarily designed for and applicable to new home projects, major gut rehabs can qualify. (LEED v4 New Construction) requires that indoor water use be reduced by 20%, and offers additional credits for reducing water use even further. But the consequences of that reduced water flow have ledLight-emitting diode. Illumination technology that produces light by running electrical current through a semiconductor diode. LED lamps are much longer lasting and much more energy efficient than incandescent lamps; unlike fluorescent lamps, LED lamps do not contain mercury and can be readily dimmed. to concerns about water quality in green schools across the country.

Energy Predictions vs. Energy Performance

Posted on March 21, 2017 by Kent Earle in Guest Blogs

Editor's note: Kent Earle and his wife, Darcie, documented construction of their superinsulated house on the Canadian prairies in a blog called Blue Heron EcoHaus. GBAGreenBuildingAdvisor.com published a number of those posts in a series that wrapped up last year. Recently, Kent wrote to say he has been monitoring energy use at the house and offered this followup.

Is This SIP Roof In Trouble?

Posted on March 20, 2017 by Scott Gibson in Q&A Spotlight

Matt Melton lives in central Washington state in a 3-year-old house with a roof made of structural insulated panels (SIPs) that are 12 1/4 inches thick. The pitch of the roof is very low, only 1/2 inch-in-12, and the metal roofing has been applied directly over the SIPs with no air channel beneath the roofing for ventilation.

Installing Closed-Cell Spray Foam Between Studs is a Waste

Posted on March 17, 2017 by Martin Holladay in Musings of an Energy Nerd

Open-cell spray foam has an R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of about R-3.7 per inch, while closed-cell spray foam has an R-value that may be as high as R-6.5 per inch. If you want to install spray foam in a stud wall, and price is no object, then it would seem to make sense to specify closed-cell spray foam, right?

Not necessarily.

Pete’s Puzzle: Fanciful Fuel

Posted on March 16, 2017 by Peter Yost in Building Science

A new client called me, saying that his insulation contractor urged him to contact me about some moisture problems in the home before they actually embarked on a major energy upgrade. (That was gratifying.) The home was actually moved many years ago off of a failing rubble foundation to a new concrete masonry unit (CMUConcrete masonry unit. Precast concrete block used to build walls. CMUs have hollow cores that can be filled with concrete onsite for additional reinforcement. The use of stronger, more lightweight types of concrete such as autoclaved aerated concrete (AAC) is becoming increasingly popular in CMU manufacture. ) foundation on a different site.

Image #2 (bottom of page) shows the home from the front. Image #3 shows the bare CMU on the above-grade portion of CMU foundation.

But it is Image #1 (right) that is the real puzzle. Here are the puzzle pieces:

Does a Bigger Volume Mean More Heating and Cooling Load?

Posted on March 15, 2017 by Allison A. Bailes III, PhD in Building Science

What happens to the heating and cooling loads when you encapsulate an attic? With the insulation and air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both. at the ceiling below the attic, you're excluding the attic space. That volume of air up there isn't involved in the conditioning of the home. But when you move the enclosure to the roofline (usually by installing spray foam insulation beneath the roof deck), now the attic's volume is included in the conditioned spaceInsulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort. .

Occasionally I hear people say the loads will be higher because of the extra volume. Does having more air inside really increase the loads?

My Net Zero Conundrum

Posted on March 14, 2017 by Anonymous in Guest Blogs

By JEAN CARROON

Why would we want an individual building to be its own energy plant? This has never made sense to me. The scale seems inefficient and the potential of many existing urban buildings for net-zero energyProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines. (NZE) is limited. But many people I admire seem besotted by NZE. What am I missing?

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