Energy audits also use thermography to discover air leakages. This is done by assigning an estimated R-value to a building's envelope. Thermographs of the envelope are then taken and analyzed to determine the relative temperature differences (hot vs. cold) of an envelope's features. Significant temperature differences indicate leakage points. Common leakage points are around window and door frames, hollow wall cavities, attic spaces, and other holes cut into the envelope. After being identified, leakage points are properly insulated and sealed
Occupant satisfaction is an overlooked, but equally important metric. To measure satisfaction, a survey, with questions relating to each of the aforementioned category, was issued. lf over 20% of responses to questions about a specific category indicated dissatisfaction, we revisited our approach to that category.
Money saved by following our model was put towards the installation of additional, passive energy saving features in each building, which further reduced HVAC demands and their consequent costs.
Dunbar High School, which is recognized as The "Greenest School in the World", is a notable case study. It earned the U.S. Green Building Council's (USGBC) highest distinction, LEED Platinum certification.
Dunbar scored 91 out of a possible 110 points possible for LEED, making it the highest- scoring newly constructed K-12 school in the world. Dunbar's new campus raises the bar for sustainable building design and environmental stewardship.
Notable enhancements include:
► 482 kW photovoltaic array(provided through Washington, DC's first power purchase agreement) that generates enough energy on a sunny summer day to power all classroom lights for eight hour.
► Washington, DC's largest ground-source heat pump, or "geothermal" system below Dunbar's athletic field, with wells extending 460 feet deep
► The reopening of O Street as 6,152 square feet of rain gardens able to handle a 1.2-inch storm event
► Pervasive natural light resulting from proper orientation and shading of the building.
► Two 20,000 gallon cisterns and low-flow fixtures help save over 1,400,000 gallons of potable water/year.
► Enhanced acoustics that help create a high-performance learning environment
10 months after opening, Dunbar's engineer, architect, facilities manager, head administrator, and owner met to discuss operational procedure, schedule, and HVAC temperature set points. Decisions generated by this meeting reduced Dunbar's energy consumption by 40%in the summer and by 20% in the fall, ultimately saving the school an estimated 550,000 in yearly utility costs. The diagram illustrates Dunbar's HVAC usage before and after the meeting.