The zero-carbon train has left the station for housing and is the future for the industry, Sam Rashkin, the founder of Retooling the U.S. Housing Industry, told listeners as part of a recent webinar hosted by Buildxact. Rashkin said getting to zero carbon is a journey and there are “various steps on the path that are viable and fair choices for builders.”
Energy codes have become more rigorous over time, including a 40% increase in rigor over the past 10 to 15 years, and many states are adopting codes that are targeting zero carbon. Rashkin said average HERS scores are becoming lower and lower, and state policies are making major commitments to become carbon free in the near-term future, underlying the importance and value of zero-carbon building. While zero-carbon homes can deliver higher performance, Rashkin said they are not without their risks as well.
“If you look at the homes built in the mid-'70s, they were pretty inefficient, and, of course, we wanted to go toward high-performance enclosures. They [offer] lower bills, more comfort, and more safety,” Rashkin said. “But I’m transparent, you’ve got to know there’s greater risk. As we increase the performance of the enclosure, we are taking on substantially greater risks of moisture, comfort, and indoor air quality. It doesn’t mean we don’t do high-performance enclosures, it means we do them and we manage the risk.”
Throughout his presentation during the “How to design and build all-electric homes in a smart, profitable way” webinar, Rashkin outlined basic and simple building blocks to help builders get to zero carbon “efficiently, effectively, and with the best results,” such as moving HVAC systems from the attic, using thin triple low-E windows to maximize efficiency, or using insulated foundation forms that combat thermal bypass problems between. The first step is to start with the high-performance enclosure and optimize energy, air leakage, moisture control, and vapor control.
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