The most recent blogs at Green Building Advisor

High-Performance and Net-Zero Homes — Part 5

Posted on April 2, 2012 by Ann Edminster, GBA Advisor in Green Building Blog

In the prior installment in this blog series, I proposed a rationale for the adoption of integrated project delivery (IPD) and promised to follow with suggestions regarding its implementation, along with some resources.

Energy Modeling Isn’t Very Accurate

Posted on March 30, 2012 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Energy consultants and auditors use energy modeling software for a variety of purposes, including rating the performance of an existing house, calculating the effect of energy retrofit measures, estimating the energy use of a new home, and determining the size of new heating and cooling equipment. According to most experts, the time and expense spent on energy modeling is an excellent investment, because it leads to better decisions than those made by contractors who use rules of thumb.

Window Performance 2 — the Magic of Low-e Coatings

Posted on March 29, 2012 by Alex Wilson in Energy Solutions

Last week I wrote about the early strategies window manufacturers employed to improve energy performance: adding extra layers of glass and increasing the thickness of the airspace between the layers of glass. This week we'll look at a more revolutionary change to window design that appeared in the 1980s: low-emissivityAmount of heat radiation emitted from a particular body or material. Emissivity is expressed in a fraction or ratio, with the lowest values indicating low emissivity and the highest indicating the high emissivity of flat black surfaces. coatings.

A Real Chainsaw Retrofit

Posted on March 28, 2012 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

When workers need to insulate the walls and roof of an existing building with exterior rigid foam, it often makes sense to cut off the roof overhangs first. With the eaves and rakes removed, wrapping the building in rigid foam is a snap. The missing roof overhangs can later be rebuilt by scabbing the necessary framing on the outside of the foam.

A Green Builder’s 21st Century Alphabet

Posted on March 28, 2012 by Carl Seville, GBA Advisor in Green Building Curmudgeon

One of my favorite things to hear from a design or building professional is that they are “LEED Certified.” This is only slightly less amusing than when they refer to LEEDS certification. In the case of the former, only buildings can be certified (although some people are certifiable); people are accredited, as in LEED AP, or accredited professional.

A Net-Zero-Energy Home in Rural Tennessee

Posted on March 27, 2012 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

On my thousand-mile quality assurance road trip last week, I visited a house that was designed to produce more energy than it uses, making it a net zeroProducing 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. Calculating net-zero energy can be difficult, particularly in grid-tied renewable energy systems, because of transmission losses in power lines and other considerations. energy home. You can take any house all the way to net zero just by giving it enough on-site power production (photovoltaics, wind, hydropower...), but that's not the most effective way to achieve the goal of net zero energy use. First, you want to make the house really efficient, and that's what these folks did.

Should I Turn Down Radiant-Floor Heat at Night?

Posted on March 26, 2012 by Scott Gibson in Q&A Spotlight

Does it pay to turn down the heat at night when you have a radiant-floor heating system? David Meiland and a heating contractor are having trouble seeing eye to eye on that question.

Meiland says the house they're discussing is a slab-on-grade with R-10 insulation below and PEXCross-linked polyethylene. Specialized type of polyethylene plastic that is strengthened by chemical bonds formed in addition to the usual bonds in the polymerization process. PEX is used primarily as tubing for hot- and cold-water distribution and radiant-floor heating. tubing cast into the slab. In another part of the house, the floor is framed, with PEX installed below in tandem with aluminum plates that help distribute the heat. The boiler is a 30-kW electric model with an outdoor reset.

Solar Thermal is Dead

Posted on March 23, 2012 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

In the northern half of the U.S. — and even much of the South — installing a residential solar hot water system doesn’t make any sense. It’s time to rethink traditional advice about installing a solar hot water system, because it’s now cheaper to heat water with a photovoltaic (PV) array than solar thermal collectors.

In short, unless you’re building a laundromat or college dorm, solar thermal is dead.

The Revolution in Window Performance — Part 1

Posted on March 22, 2012 by Alex Wilson in Energy Solutions

I've been working for the past couple weeks on a report on windows — the latest in BuildingGreen's series of special reports on green building (the last one covering insulation). This focus has reminded me just how much we expect of our windows and what an amazing job they do.

Evolving Opinions on Green Building

Posted on March 21, 2012 by Carl Seville, GBA Advisor in Green Building Curmudgeon

I still remember using spray foam insulation in my early green renovation projects – it was almost magic! It sealed and insulated in one shot. It made it easy to finish attics and avoid most of the problems with fiberglass batts that were the common insulation on our jobs.

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