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.