Austin Can Reduce Energy Needs

Studies show that we can cut our projected energy with energy efficiency, renewable energy and combined heat and power, which captures wasted energy.

Citizens are urging the Public Utility Commission (PUC) to increase in the utility savings targets.


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Report by the Austin Zero Energy Homes Task Force, Oct. 2007

Final report to Austin City Council

Authorization

On August 10, 2006, the City Council passed resolution No. 20060810-060 directing the City Manager to create a task force to develop a plan for consideration by Council that by 2015 all new single-family homes be built as "Zero Energy Capable Homes."

Implementation

A task force representing local construction industry trade associations (including builders, HVAC and other trades), affordable housing providers, energy efficiency advocates, the City Resource Management Commission, the Electric Utility Commission, Texas Gas Service, and City staff was created and began meeting in September, 2006. The members of the Task Force are listed on Appendix 1.

The task force initially developed a charter laying out 3 high level deliverables. Those deliverables are:

Recommendations to council regarding proposed local amendments to the 2006 International Energy Conservation Code (IECC) for adoption as City of Austin Energy Code;
Goals for energy efficiency improvements for the IECC code cycles 2009, 2012, and 2015; and
A process and plan for passing responsibility for oversight of the project to the City of Austin Resource Management Commission.

Defining the Goal of Zero Energy Capable Homes

The Task Force defined a Zero Energy Capable Home as:

"homes that are energy efficient enough to be net zero energy homes with the addition of on-site or its equivalent, energy generation. This level of energy efficiency is approximately 65% more efficient than homes built to the City of Austin Energy Code in effect in November, 2006."

Local Amendments to the 2006 International Energy Conservation Code

Between October, 2006 and April, 2007 the task force reviewed, discussed and approved a package of local amendments to the IECC that, if approved by council, will improve overall (electric and gas) efficiency of homes built to that code by 11%. Use of electricity will be reduced by 19% and use of gas reduced by 1%. The focus of these amendments was improvement of air conditioning systems, which are the major user of energy in typical homes in the Austin area. The primary amendments are:

  • Requirement for building thermal envelope testing.
  • Requirement for installation of a radiant barrier system.
  • Requirement for testing of duct system leakage.
  • Requirement for submittal of HVAC sizing calculations.
  • Requirement for testing of air balancing of HVAC systems.
  • Requirement for system static pressure testing.
  • Revision of the restriction on electric resistance water heating.
  • Requirement for 25% of lighting to be high efficacy.

Energy savings per home are 2515 kWh of electricity and 4 therms of gas.
This will reduce energy costs for a typical home by $227.68 per year. The local amendments will increase the cost of building a home by $1,179. Thus the estimated payback period for these amendments is 5.2 years, or approximately 20% per year.
The proposed local amendments to the 2006 IECC are in Attachment 2.

Goals for Future Code Adoption Cycles

Major revisions are made to the International Energy Conservation Code (IECC) every three years. The 2006 version of the IECC is the first code adoption cycle which falls under the purview of the Task Force.

The methodology used to determine progress toward meeting the goal of Zero Energy Capable Homes was to perform computer building energy modeling on a typical new home built in Austin in 2006. This modeling has been performed on a home plan provided by a volume builder building in the City. A baseline for energy use has been established and local amendments have been modeled to determine progress made with the local amendments for 2006. The baseline is established using computer energy modeling of a typical home currently being built by a volume builder in Austin. That home is of approximately average size for a new home in Austin. The home is modeled using specifications that meet the current energy code to establish the baseline energy use. The same home plan is then modified using specifications based on the 2006 IECC with local amendments to determine energy savings. Modeling has also been done to determine the effectiveness of potential local amendments for 2009 and 2012. The table below shows baseline energy use, percent energy reduction goal for each cycle, energy use in MBTU per home for the goals, incremental MBTU (Thousand British Thermal Units) reduction for each cycle goal, and the resulting CO2 emissions per 1,000 homes under the goals.

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