(CS3.2) Conservation and Carbon: The Campus Context

Higher education campuses are a unique sub-set of building owners: they own large portfolios of buildings that vary in size, age, and program, and very often including buildings of historic significance; they pay to operate and maintain their buildings and therefore have a vested interest in both energy efficiency and long-term durability. Many campuses across North America are also modeling leadership in environmental stewardship and climate mitigation, committing to drastic reductions in carbon emissions.

One key part of many campus decarbonization strategies is to convert the existing district energy systems from natural gas to low-carbon electricity. This often means converting the existing hot water/steam system (180F/80C) supplied by natural gas boilers to a lower temperature heating water system (100-120F/40-50C) supplied by electric heat pumps. And as the lower temperature water distribution is most effectively implemented when it is matched to a reasonable heating demand, this change in heating system triggers the need for building envelope thermal performance upgrades.

This conversion of heating system fuel source from natural gas to electricity coupled with building envelope thermal performance upgrades is a typical deep energy retrofit strategy. Deep energy retrofits are retrofits of existing buildings where efficiency measures are implemented to achieve a reduction in energy consumption of 50% or more (compared to the pre-retrofit performance). Deep energy retrofits are also characterized by efficiency measures that are integrated and interdependent, going "deeper" than typical no-cost/low-cost measures such as upgrading to energy-efficient lighting or seeking marginal improvements in efficiencies at the time of equipment replacement.

Deep energy retrofits can be challenging for buildings with historic significance because, for the reasons described above, they nearly always necessitate interventions involving the building enclosure. While the building enclosure may have previously been "off limits" for energy efficiency measures in some buildings due to concerns about the risk of damaging the heritage fabric, the choice not to improve the performance - unless clearly justified - is increasingly recognized as contributing to a different type of risk: a climate risk. In this context, conservation practitioners must work closely with energy analysts, building scientists, and other project team members to holistically weigh the risks and benefits of proposed efficiency measures for deep energy retrofits of historic buildings.

This presentation highlights short case studies from several deep energy retrofit projects of buildings of heritage significance on university and college campuses across North America, including the Red River College (Winnipeg), University of Toronto, University of Windsor, McGill University, Yale University, and Harvard University. Projects are in various stages of completion; some are recently completed while others are still in progress.