Science & Technology

It may be time to reconsider the energy efficiency exemption of historic buildings

It may be time to reconsider the energy efficiency exemption of historic buildings

Anna Gasha
|January 18, 2022

Despite years of rhetoric, old buildings are not always eco-friendly. According to a recent analysis, for example, the Federal Reserve Bank of New York in 1919 exceeded its 2024 emission target, while the 1920 US Stock Exchange building is still present. (Photo: Beyond my ken When R Majoji).

It is now well established that the construction industry and the building environment contribute significantly to greenhouse gas emissions and energy consumption. for example, 70 percent Of the greenhouse gas emissions in New York, it comes from buildings. Nevertheless, despite the fact that many municipalities have adopted stricter energy code requirements in recent years, US historic buildings continue to be exempt from energy performance and environmental impact.

This situation has been largely unproblematic since the exemptions of these energy laws for historic buildings began in the 1970s. Since then, conservationists have claimed that older buildings are on average more energy efficient, but there isn’t much data to support this claim.

Our team led by a professor at Columbia University Erica AvramiThinks it may be time to reconsider the exemption of these default energy codes for historic buildings.and Recent research, We try to straighten the record: Despite years of conservationist rhetoric, old buildings no Always eco-friendly.In fact, the energy code exemption Historic monuments Cities like New York are in a more difficult position today as they begin to force greenhouse gas emissions to combat the climate crisis —Without it Exemption from historical status.

Quantifying the problem: New York City as an example

In recent years, more data sources on building energy usage have become available, allowing us to analyze how “green” an old building really is. Many cities and states carry out energy audits and benchmarking programs, and owners of both non-historical and historic buildings are obliged to disclose energy performance indicators for properties above the specified square foot. I have. New York City is one of the municipalities that has implemented such policies since 2009. Ground method 84 Since it was expanded Ground method 133 In 2016.

Using this reported 2018 benchmark data, in our study, the conclusions of the 1977 study of office buildings of various ages in New York City underpin the claim that older buildings are more environmentally friendly. However, in reality it is controversial. Not only did this early study examine a fairly limited sample to draw these conclusions, but their findings are based on a comparison of average energy consumption over different decades of construction. The average is an inadequate measure of energy performance because it cannot show the volatility and extent of energy consumption data and produces a single misleading value that characterizes the performance of a building over a particular time period. The 2018 benchmark data provided more data points than previous surveys and created a more robust overview of existing building stock. This more recent dataset shows that the range of energy consumption in older office buildings has increased over time. In short, these conclusions cast doubt on the generalization that older buildings have inherently better energy performance.

30 Rock Building and Empire State Building

The 1930 building, now known as the 30 Rockefeller Plaza, exceeds its 2024 emission target. The 1929 Empire State Building has achieved that goal. (Photo: Library of Congress)

Is it too late to adapt?

This more accurate understanding that not all old buildings are more environmentally friendly and, in fact, the energy consumption of some older buildings is very high raises an urgent problem. Are historic buildings ready to face a climate crisis?

The long-standing exemption from the energy code of historic buildings suggests that the answer is a bit difficult. The code revisions, which take place every few years, generally make the requirements more stringent at each iteration to improve energy performance by taking into account previously unavailable technologies and methods. Most existing buildings respond to these changes, and their owners respond accordingly through refurbishment, a selection of cleaner energy options, and other means. This series of regular updates makes each change a little bit more manageable.

In contrast, historic buildings did not have to keep up with changes in energy code requirements through such cumulative updates. This stagnation makes it difficult to imagine what would happen if a historic building were suddenly constrained to the same energy requirements as other buildings. They save decades of energy to catch up, incur significant costs and complex refurbishment projects. The enormous amount of tax exemption illustrates the seriousness of this challenge. In the case of New York, analysis shows that about one-third of Manhattan’s building floor space is exempt from historical status-based energy codes.

Recent New York City legislation limiting greenhouse gas emissions from buildings has broken the pattern of exempting historic buildings. Ground method 97, Within 2019 in the city Climate Mobilization LawSpecifies the emission limits that buildings above the threshold square foot must meet by 2024. Some of the affected buildings have designated historical assets. Exemption. This provision requires many owners to face a steep energy efficiency “learning curve” if these historic buildings meet the limitations of Land Method 97. Benchmark data gives a glimpse of future issues. Based on the values ​​reported in 2018, about a quarter of the designated historic assets covered by Land Method 97 exceed emission limits.

Distribution and concentration of historic building areas affected by the Greenhouse Gas Act by the census zone.

Distribution and concentration of historic building areas affected by the Greenhouse Gas Act by the census zone. Source: Avrami et al. 2021

Extensive challenges

Although our study focused on New York City as a case study, greening historic buildings, which have long been exempt from energy law, is a national issue.

To assess how widespread such exemptions were, we also looked at building codes used throughout the United States. Checking the state’s energy code shows that in all 50 states and the District of Columbia, buildings registered or eligible for National Register of Historic Places are considered “historic” and exempt. I did. Some state-level codes grant exemptions to buildings designated in state and local historic registries, further expanding the number of buildings that can circumvent energy code provisions.

Given the ubiquity of tax exemptions, the pressing challenge of retroactive greening of historic buildings cannot be denied. Reassessing the relationship between the historic building environment and the climate crisis is more important than ever. These challenges need to be faced not only by conservationists, but also in close collaboration with climate scientists and others familiar with the fight against the climate crisis. Partnerships and lasting and meaningful conversations.

Anna Gasha is a PhD student in Historical Conservation. Jennifer Most and Shreya Ghoshall are also co-authors of this study.

It may be time to reconsider the energy efficiency exemption of historic buildings It may be time to reconsider the energy efficiency exemption of historic buildings

Back to top button