The 2018 IECC, adopted by Texas, offers multiple compliance pathways for new residential buildings. Each method ensures homes meet or exceed energy efficiency standards while allowing flexibility in design and construction.
✅ Key Takeaways:
– Blower door testing is required statewide.
– Duct leakage testing is required if ducts are outside conditioned space.
– ASHRAE 62.2 ventilation requirements apply to all new homes.
Texas builders can choose from four approved pathways for IECC compliance:
1. Prescriptive Pathway (Simplest Option)
✔ Follow the IECC’s prescribed insulation, window, and system efficiency requirements.
✔ No additional energy modeling is required.
👉 Best for: Builders who want a straightforward checklist approach.
2. Total UA Alternative (REScheck Software)
✔ Allows trade-offs between insulation and window performance.
✔ The UA (U-factor x Area) of the proposed design must be ≤ the baseline home.
✔ Requires REScheck software analysis for approval.
👉 Best for: Builders needing flexibility in insulation and window choices.
3. Simulated Performance Path (Energy Modeling Required)
✔ Allows trade-offs between building envelope and mechanical systems.
✔ The home’s modeled energy use must be ≤ the baseline home’s energy use.
✔ Approved software includes:
– REM/Rate
– EnergyGauge USA
– Ekotrope
– IC3 (Texas A&M)
👉 Best for: Builders who want to offset lower insulation levels with higher HVAC efficiency.
4. Energy Rating Index (ERI) Path (HERS Score Required)
✔ The ERI score must be below Texas climate zone thresholds:
| Climate Zone | Max ERI Score |
|---|---|
| Zone 2 (Southern TX) | 59 |
| Zone 3 (Central TX) | 57 |
| Zone 4 (Northern TX) | 55 |
✔ Requires testing by a RESNET-certified HERS Rater.
✔ High-efficiency lighting and appliances can be used for compliance.
👉 Best for: Builders participating in energy efficiency programs like Energy Star Homes.
Mandatory Requirements for All Compliance Pathways
Regardless of which compliance pathway is chosen, all homes must meet these mandatory provisions:
✅ Blower Door Testing to verify air leakage (≤5 ACH50 in Zones 2 & 3, ≤3 ACH50 in Zone 4).
✅ Duct Leakage Testing (if ducts are outside the conditioned space).
✅ Mechanical Ventilation per ASHRAE 62.2 (if ACH50 is below 5).
✅ Setback Thermostats for all heating/cooling systems.
✅ Proper HVAC Sizing based on ACCA Manual J.
✅ High-Efficacy Lighting (at least 90% LED, CFL, or high-efficiency fixtures).
✅ Energy Certificate posted in the electrical panel, listing insulation, window U-factors, and HVAC efficiency.
📞 888-213-3975 – Local Energy Audits – Schedule blower door, duct leakage, or ERI testing today!
