Building Science

What San Antonio Can Teach You About the 2015 IECC Energy Code

Real estate or property developers in the City of San Antonio, Texas must comply with many land use regulations, building codes, and local design and construction standards; including the 2015 International Energy Conservation Code (IECC). On January 29, 2015, San Antonio became the first city in Texas to include in their building standards the International Code Council’s (ICC), 2015 IECC’s for residential and commercial buildings. The city adopted these codes to reduce energy use and costs to homeowners and businesses. In fact, the ICC reports an increase in energy efficiency of 18 percent in new homes and 26 percent in commercial buildings after implementation of the IECC 2015 standards over the previous IECC 2009 standards. By mandating the 2015 IECC, the City of San Antonio led the state in adopting the latest energy code, and advancing their goal of net zero carbon by 2030 for all new construction in the city.

The International Energy Conservation Code (IECC)

The IECC was first created by the International Code Council (ICC) in 2000. The ICiC is the main building code organization in the United States. Their purpose is to establish codes and standards for the minimum design and construction requirements for energy efficiency, for both new and renovated buildings.The IECC has separate codes for commercial buildings and low-rise residential buildings (three stories or less in height above grade). The codes and standards ensure a design, build and compliance process in the construction of safe, sustainable structures.The ICC’s ultimate goal is to reduce the burning of fossil fuels. The burning of fossil fuels releases carbon dioxide (a greenhouse gas) into the atmosphere. Increasing carbon dioxide levels are a leading cause of global warming. Global warming is causing the occurrence of more severe weather events, the sea levels to rise, and the oceans to become more acidic. Revision of the International Energy Conservation Code occurs every three years. The most recent 2015 IECC improves energy efficiency and saves building owners money.

Differences Between the Residential 2009 IECC and the Residential 2015 IECC

The changes in the residential standards of the 2015 IECC compared to the 2009 IECC improve the potential energy efficiency of buildings in southern climate zones 2,3 and 4 (all located in Texas) from between 15.9 and 23.6 percent. The Energy Rating Index (ERI) compliance path is one of the more important changes in the residential 2015 code. The ERI rates homes by location, size, and fuel use. A score of 100 is equivalent to the 2006 IECC, and a score of zero indicates net zero energy use in a building. There are several other key additions to the 2015 energy code that are designed to improve the overall energy efficiency in residential buildings:

  • The 2015 IECC requires referencing either ASTM E 779 or ASTM E 1827 standards for building envelope air leakage testing.
  • The 2015 IECC offers three options for duct insulation:
  1. Attic supply and return ducts must be at least R-8 (if ≥3-inch diameter) and R-6 (if <3-inch diameter).
  2. Everywhere else, supply and return ducts must be a least of R-6 (if ≥3-inch diameter) and R-4.2 (if <3-inch diameter)
  3. The last options specify all ducts in the attic to be R-8 and everywhere else to be R-6
  • The 2015 IECC requires inspection of the footing and foundation, the framing and rough-in, the plumbing rough-in and the mechanical rough-in.The inspection’s objective is to improve the quality of installations, particularly that of the insulation and air barrier.
  • The 2015 IECC allows vertical doors that provide access from conditioned to unconditioned spaces to meet the fenestration (building opening) requirements in Table R402.1.2.
  • The 2015 IECC mandates that open combustion air ducts that provide combustion air to open combustion fuel burning appliances must be located outside the building envelope or isolated from the inside of the envelope.

There are also a few key additions to the 2015 energy code designed to improve the overall energy efficiency in commercial buildings, for example:

  • 2015 EICC instructs hiring of third parties for HVAC, water heating, lighting and envelope
  • 2015 IECC mandates new equipment efficiencies for HVAC with additional requirements for ventilation systems and lighting
  • The 2015 IECC improves efficiency and controls for water heating
  • The 2015 IECC mandates occupancy sensors and daylighting controls for lighting

Compliance with the 2015 IECC comes down to correct installation of energy efficient products, like the Bautex Block Wall System. The Bautex Block Wall System utilizes insulated concrete blocks that meet and surpass the 2015 IECC building codes for air leakage testing. The Bautex Block Wall System provides an R-14 continuous insulation; far exceeding 2015 IECC recommendations. Bautex Blocks are manufactured in San Marcos,Texas. The Blocks stop thermal bridging and create an insulated and energy efficient building envelope that is compliant with the latest building codes.

San Antonio’s adoption of the 2015 IECC is a step forward to ensuring that the design and construction of buildings in the city will be of the highest standards of energy efficiency, safety, and durability. The City of San Antonio has published informational bulletins on the submittal requirements for the 2015 IECC energy codes for both residential and commercial construction. These bulletins provide a preview of many of the requirements that will likely be implemented in the local jurisdiction where your next project will be located.