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.