The Evolution of a Pretty Good House
High-performance-home designer Michael Maines takes a detailed look at the new low-carbon edition of the grassroots building standard.
Synopsis: The Pretty Good House (PGH) building standard, conceived in 2011, involves using good design and proven building science to reach a practical level of performance. Since the PGH idea originated, we have gained a deeper understanding of the effect of carbon emissions on climate change. In this article, building science consultant Michael Maines describes the features of a PGH, and uses two concept-house examples to show how a PGH can incorporate low-carbon strategies.
Have you heard about the building standard that’s completely voluntary and has no set requirements? It’s called the Pretty Good House (PGH), and the idea is to use good design and proven building science to reach a practical level of performance in a durable, lovable, net zero energy–ready structure. The PGH was conceived in 2011 at a building science discussion group hosted by Performance Building Supply in Portland, Maine. Dan Kolbert, a builder in Portland and moderator of the discussion group, had grown frustrated with other performance-rating programs for being too restrictive, too resource-intensive, and too hard to convince clients to invest in. We brainstormed about what practical level of performance—and other features—a PGH would include. I wrote a blog post summarizing our discussion on GreenBuildingAdvisor.com (GBA), and the idea took on a life of its own. Recently, we updated the PGH concept to address the urgency of the climate crisis.
Incorporating embodied carbon
The release of the United Nations’s 2018 climate-change report highlighted the need to considerably reduce global warming emissions and also made evident the building sector’s significant contribution to the problem. Over the last eight years, many of us in the discussion group have developed a deeper understanding of high-performance building, so we decided to review our initial list of PGH attributes. Surprisingly, little had changed—a testament to the practical nature of our original ideas. The most critical addition was the carbon footprint of a house.
“Carbon footprint,” or “upfront carbon emissions,” can be defined as the sum of carbon emissions over a product’s lifetime—from the extracting of raw materials to its processing, shipping, assembly, maintenance, and eventual disposal or recycling. “Carbon emissions” is shorthand for carbon dioxide (CO2)–equivalent emissions. As a prevalent greenhouse gas, CO2 is used as a unit of measurement, meaning the effect other greenhouse gasses have on trapping heat are expressed as the equivalent in CO2. This matters because there is more CO2 (and other greenhouse gasses) in our atmosphere than there has been for at least 800,000 years. In fact, there is nearly 50% more carbon in the atmosphere now than there was at the start of the Industrial Revolution. Time is running out—if emissions continue at their current rates, temperatures will continue to rise. The U.N.’s team of scientists says we need to reduce emissions by 50% by 2030, and by 100% (net-zero carbon) by 2050. Those ambitious targets don’t guarantee a safe future, but they do improve the odds.
More about the Pretty Good House (PGH) Concept
A Pretty Good House in Maine – This home’s low energy bills speak louder than any performance certificate.
FHB Summit: Pretty Good House Insight Session – How do we get better energy efficiency in our homes, and how do we convince clients to want better energy efficiency?
Pretty Good House 2.0: Practical Low Carbon – High-performance-home designer Michael Maines presents a collection of easy-to-implement construction details for building more environmentally friendly houses.
From FineHomebuilding #291
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