This article has been reposted from PNNL’s January 2017 Energy and Environment Research Highlight.

During cold winter months, many Americans wrestle with the urge to splurge and head south for warmer weather. The allure of the tropics is difficult to resist, and unbeknownst to many, their destination of choice will soon require special considerations when it comes to energy savings.

In December, members of Hawaii’s energy community—including Hawaii Energy and the Blue Planet Foundation—testified during the State Energy Conservation Code Public Hearing in support of adopting the 2015 International Energy Conservation Code (IECC).

The state currently enforces the IECC of 2006, but one big change in the 2015 code has Hawaii considering an update—the addition of a tropical climate zone with tropic-specific codes. Areas covered under the newly identified zone include Hawaii, Guam, Puerto Rico, American Samoa, U.S. Virgin Islands, and islands between the Tropic of Cancer and the Tropic of Capricorn.

A February 2016 report by building energy code researchers at PNNL was cited as a driver for Hawaii considering 2015 IECC adoption. PNNL researchers, funded by DOE’s Building Technologies Office, found that adoption of 2015 IECC would lead to about 21 percent energy cost savings for residential buildings—including single-family houses, townhouses, and apartment buildings with three stories or less—in the state. "When translated into dollars, the billions in savings plainly illustrate the enormous benefit of the proposed amendments," the Blue Planet Foundation said in its testimony.

Climate-Catered Codes

Tropic-specific additions to the 2015 code include requirements for insulation, ventilation, ceiling fans, and air sealing. There is also an optional—and simplified—compliance path for semi-conditioned residential buildings that match criteria defined in the new code.

Hawaii’s energy savings from the 2015 code relative to the 2006 code were uncovered by state-specific energy analysis. PNNL’s residential codes research team simulated and analyzed energy usage and savings using a set of PNNL-developed prototype building models and DOE’s EnergyPlus™ software.

In July 2015, the Hawaii State Building Code Council unanimously approved adopting the 2015 code. With the public hearing complete, next steps to adoption include review by the Small Business Regulatory Review Board, then approval from Gov. David Ige's and the Office of the Lieutenant Governor.