Energy Systems Laboratory

International Code Compliance Calculator


City Amendments to the State Energy Code



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Can I use RESCheck to show compliance with the 2006 IECC in Texas?

No. RESCheck is a different computer software tool primarily addressing building envelope effectiveness. The 2006 version is meant to be used with the 2006 version of the IECC. The state charged Energy Systems Laboratory (ESL) with verifying stringencies between the 2000 version of the International Energy Conservation Code (IECC) with 2001 Amendments and any versions published afterward. In comparison, the 2006 residential provisions were determined to be less stringent. To address this situation, the North Central Texas Council of Governments (NCTCOG) developed a package of amendments that redefine climate zones and provide the correct insulating values for building performance according to those climate zones. The recommended amendments to the 2006 International Energy Conservation Code compensate for the differences. If a municipality adopts the 2006 IECC along with the NCTCOG amendments, they are in compliance with state law. IC3 is a software tool designed to be used with the 2006 IECC and NCTCOG amendments combined. IC3 is a “performance” based computer software tool which addresses specific performance values of construction including the envelope but also including efficiencies of equipment, different power sources, location of equipment, etc. It allows you to compare your “proposed” design to the “standard” design already simulated in the calculator. Using IC3 allows you see how much above code or below code your “proposed” construction would be.

Where is the 2006 IECC w/ NCTCOG amendments in the drop down tool?

In terms of stringency, Energy Systems Laboratory (ESL) determined that the 2006 International Energy Conservation Code (IECC) is less stringent than the 2000 IECC with the 2001 Supplement. Therefore, the laboratory worked closely with the North Central Texas Council of Governments (NCTCOG) to develop a set of amendments to the 2006 IECC. The 2006 IECC w/ NTCOG amendments is the same as the 2000 – 2001 IECC option.

I am confused. How do I know which code option to choose?

The “IECC 2000/2001” option should be used if you need to show compliance with the 2000 International Energy Conservation Code (IECC) or the 2006 IECC with the North Central Texas Council of Government Amendment package. The “IECC 2006 Houston” option should be selected only if you are trying to obtain compliance with Houston’s 15% above-code initiative. “IECC 2009” is your choice to show compliance with the 2009 IECC.

How does an IC3 User access older projects in IC3?

You can access your older projects from “My Page”. Initially, IC3 displays the last projects entered into IC3. If you need to find projects that are being stored that are older than the last ten projects, then simply click on the “Search” button (with nothing typed in the search field). This will open the “project scroll function” and the ability to scroll through all of the projects that you have access to. In version 3.10 (released in 2011), you can set the number of projects being displayed in the lower right hand corner of the screen, as well as the ability to do simple sorting of projects.

How do I use the “Texas A&M Duct Trade-Off Option” in IC3?

Recent enhancements to IC3 make it easier than ever to indicate the use of the “Texas A&M’s Duct Trade-Off option”. Simple indicate the Supply and Return values in the indicated fields on the “Insulation/Mechanical” page and the SEER value on the HVAC/DHW page. **Note – The “Duct Trade-Off Option” should not be used with the “IECC 2009” code selection.

Why won’t the software calculate an addition on the back of a house?

IC3 isn’t presently configured to do additions, only new single family residences.

IC3 allows Solar Heat Gain Coefficient and U-Factors greater than what is allowed for the climate zone where my project is located. Is this a defect with the software?

No, this is not a defect. IC3 has been developed to allow the user to enter the values for SHGC and U-factor that would comply with the State of Texas energy code requirements. It is also intended to demonstrate our interpretation of the simulated performance approach. IC3 allows the user to enter SHGC and U-Value values that may not meet the minimum for a certain area, but will allow the user to see how the entire building will perform according to the users’ input. Minimum values for SHGC and U-Value may be dictated by a jurisdiction’s currently adopted energy code, or by amendments that the jurisdiction has adopted. It is the responsibility of the jurisdiction and its inspectors and plan reviewers to ensure that current minimums are being met; both at the plan review stage and during construction/inspection stage.

How does the emissions calculator work?

Our sytem combines an allocation of power providers for the county selected, and a series of “look-ups” from the EPA’s eGrid database. The results are then applied to the energy savings and are displayed.

What does a reduction in tons of CO2 emissions mean?

The EPA’s Greenhouse Gas Equivalencies Calculator is a good start. Perform a web search on “reduction in carbon dioxide equivalent” on the EPA website also yield good explanations from a variety of sources. Comparing CO2 reductions to cars being taken off of the road is a poor example sometimes, but works for some.