The short version of energy use in New York City is a bit confused: lighting buildings at night and air-conditioning everything in sight seems wasteful, while the apartment- and transit-heavy nature of the city saves a lot of energy over the more typical American pattern of single-family homes and car transport. The long version is far more complicated and in the end can only be understood by collecting a lot of data about where our energy goes.
The city began collecting the information a few years ago. Local Law 84 of 2009 requires owners of buildings to report data on energy and water use, and the reports make for fascinating reading. The first report provided a benchmark against which future data can be measured, and subsequent reports provide the data needed to set policy. This interacts my world in an interesting manner: the data show that older buildings tend to perform better on energy use. It’s tempting to say that’s because of the manner in which they were built, but that conclusion isn’t necessarily true. It may be, for example, that newer buildings house occupants that use more energy (data centers versus offices). But regardless of the reason for the discrepancy, the fact that older buildings are performing better is yet another reason that our goal of keeping them in service makes sense.
I’ve said repeatedly – perhaps pounded into the ground – the concept that preserving old buildings saves energy. That’s obvious, I think: it takes less energy to alter or repair an existing structure than it does to demolish it, dispose of the debris, and construct a new building from new materials. But the benchmarking results show that there may be a double benefit, which is okay with me.