Do Building Codes Actually Save Energy?

According to a new paper (abstract here; pdf here) by the environmental economists Grant Jacobsen and Matthew Kotchen, the answer is yes.
The gist:

While the vast majority of states have energy codes in place, policymakers are now attempting to legislate energy codes at the federal level to help address more recent concerns about energy efficiency and climate change. Nevertheless, surprisingly little is known about whether energy codes are an effective way to reduce energy consumption in practice. This paper provides the first evaluation of an energy-code change that uses residential billing data on both electricity and natural gas, combined with data on observable characteristics of each residence. The study takes place in Gainesville, Florida, and the empirical strategy is based on comparisons between residences constructed just before and just after Florida increased the stringency of its energy code in 2002. We find that the increased stringency of the energy code is associated with a 4-percent decrease in electricity consumption and a 6-percent decrease in natural-gas consumption. The pattern of savings is consistent with reduced consumption of electricity for air-conditioning and reduced consumption of natural gas for heating. We also estimate economic costs and benefits and find that the private payback period for the average residence is 6.4 years. The social payback period, which accounts for the avoided costs of air-pollution emissions, ranges between 3.5 and 5.3 years.

Related: Jacobsen’s job-market paper was called “The Al Gore Effect: An Inconvenient Truth and Voluntary Carbon Offsets.” In summary:

This paper examines the relationship between climate change awareness and household behavior by testing whether Al Gore’s documentary An Inconvenient Truth caused an increase in the purchase of voluntary carbon offsets. I find that in the two months following the film’s release, zip codes within a 10-mile radius of a zip code where the film was shown experienced a 50 percent relative increase in the purchase of voluntary carbon offsets. During other times, offset purchasing patterns for zip codes inside the 10-mile radius were similar to the patterns of zip codes outside the 10-mile radius. There is, however, little evidence that individuals who purchased an offset due to the film renewed them again a year later.