Buildings Energy & Emissions Water

Green Rehab Experiment: Engaging Tenants Toward Net Zero Energy

Believe it or not, buildings use an estimated 40% of all energy consumed in the United States. That’s a big contributor of greenhouse gas emissions, and although we can now construct extremely energy efficient buildings like the Bullitt Center in Seattle, we still need to worry about all of the existing ones that were built decades before energy efficiency was strongly considered in building design. Luckily, that’s where Washington University’s Green Rehab Experiment comes in, where a century-old apartment building north of the University City Loop has been retrofitted with highly efficient systems, making its energy efficiency performance significantly better than many new “green” buildings.

The Green Rehab Experiment is a multi-year interdisciplinary project aimed at studying renovation strategies in two previously identical apartment buildings owned by WashU’s off-campus housing affiliate Quadrangle Housing. The control building was retrofitted according to standard specifications, while next door, the experimental unit received thicker insulation, more efficient heating and cooling, and a number of other tweaks that, with the addition of a rooftop solar array, translated to a 74% reduction in carbon emissions compared to the control.

One important question involves determining whether the experimental building can reach a state of Net Zero Energy, where it annually consumes only as much energy as it produces. An array of solar panels on the roof has been producing electricity for over a year, but during that period the building has consumed more energy than the solar panels produced. Instead of increasing the size of the solar array, project members are focused on finding ways to lower the building’s already lean energy consumption even further.

This semester, a team of students enrolled in the Sustainability Exchange is examining whether engaging the apartment’s occupants in energy-saving habits can drastically reduce the building’s overall consumption. Measures may include meeting and surveying occupants and distributing user manuals that describe the apartment’s energy-saving features. The effectiveness of these strategies will be measured by analyzing data from energy meters that record electricity use from a number of sources in each apartment unit. The students hope to have preliminary answers to present at the Sustainability Exchange poster symposium in December.

Lessons learned from the Green Rehab Experiment aim to provide direction not only to Quadrangle Housing’s $100 million multi-year effort to renovate 850 living units but also to other similar housing stock in St. Louis and across the United States.

This article was written by Colin Keating, a Green Rehab Program Associate.