As the year 2030 gets closer and closer, significant industry discussion has focused on aligning energy codes and standards to drive efficient new construction. Yet, it is estimated that almost 75% of the building stock in the United States is over twenty years old, a time before energy codes were used more consistently across the country. It is estimated that 3% of our existing building stock will need to be deeply energy retrofitted every year, in order to meet 2030 greenhouse gas emission reduction goals.
Interestingly, members of the historic preservation community have been driving change to improve the energy efficiency of existing buildings. In 2017, ASHRAE will be releasing Guideline 34P, a reference document focused on energy efficiency in historic buildings. Current energy standards generally exempt historic buildings from having to meet provisions. There is now a movement to reverse these exemptions and instead have the buildings most representative of our history be at the forefront for how to best renovate buildings of all types and vintages. The National Trust for Historic Preservation and Preservation Green Lab released a study showing the embodied energy benefits of building reuse.
So which characteristics of historic preservation align with sustainability?
- A significant number of historic buildings were designed for passive lighting and ventilation strategies, without spatial allocation for modern building systems. This has triggered significant demand for creative solutions that focus first on heating and cooling load reduction, followed by the use of systems that utilize refrigerant or water for conditioning energy delivery instead of air.
- Building science has been brought into historic buildings for several decades, due to concern over the impact of energy efficiency measures on mass masonry walls. This research has benefited the entire building industry. Analysis tools and technologies now are utilized across all building types.
- The desire to preserve heritage properties aligns with the broader goals of environmental stewardship. If climate change is not addressed, the effort the community has made to preserve our history will be lost to disruptive global change.
Addressing the efficiency of all our buildings is the best way the honor the legacy of the modern preservation movement.