Performance Contracting
Located in the Loudoun County Historic District, Aldie Elementary School was the first school built in the town of Aldie and currently serves 110 students in Loudoun County Public Schools (LCPS). Built in 1928 with additions in 1950 and 1965, the school is a designated historic building, and, as a result, exterior modifications required review and approval from the Loudoun County Historic District Review Committee. The brick building includes classrooms, cafeteria/multipurpose space, kitchen, library, and administrative areas.
Due to the COVID-19 pandemic, LCPS needed to renovate the school to provide outside air ventilation at levels meeting ASHRAE 62.1 standards, as well as modernizing the building energy and envelope systems. Starting in September 2020, CMTA Energy Solutions developed and designed an energy savings performance contract (ESPC) project to include a full HVAC renovation, LED lighting, water efficiency upgrades, and building envelope improvements—all constructed over the summer of 2021 without disrupting the educational school year. As a result, the project transformed this 16,299-square-foot school from the district’s highest energy consumer per square foot to one of LCPS’ most efficient schools.
Working closely with LCPS staff, CMTA Energy Solutions evaluated multiple HVAC options, selecting a ground source heat pump (GSHP) solution with a dedicated outdoor air system (DOAS) as the most suitable, cost-effective, and efficient HVAC system. As the first GSHP system installed at an LCPS facility, it is an all-electric, energy-efficient solution that preserves and enhances Aldie Elementary School’s historical characteristics. Due to the project’s success, LCPS is currently constructing GSHP systems at two additional schools designed to become zero-energy facilities post-construction, further reducing the district’s carbon footprint.
The historic building also needed several improvements to tighten the existing envelope, reducing energy loss due to infiltration and improving occupant comfort. Pre-renovation, the suspended ceiling was the only separation between classroom spaces and the uninsulated attic, causing occupant discomfort. Therefore, the design team added R30 attic insulation with a vapor barrier sealed at the perimeter walls. The historic wooden windows were also fully refurbished, including the addition of weather-stripping for all the sashes and the caulking of interior and exterior frames. Interior storm windows with low-E glass were installed to reduce heat gain/loss. These improvements not only decreased energy consumption, but they also improved occupant comfort by making the spaces more uniform in temperature, eliminating cold drafts and hot spots from the windows and attic during the heating and cooling seasons.
The renovation project reduced the building’s EUI from 137.4 kBTU/SF/yr to 40.5 kBTU/SF/yr, a staggering 70% savings in energy use. The drastic savings are a result of the envelope improvements, efficient equipment installed, and optimization strategies implemented for operating the new system.
