Ventilation Requirements in Texas
The 2018 IECC, adopted in Texas, mandates that all new homes must include a continuously operating mechanical ventilation system to maintain indoor air quality.
✔ Ventilation systems must provide fresh air intake and stale air exhaust.
✔ Must operate continuously or cycle at least once every four hours.
✔ Manual override control is required for all systems.
These systems must be designed according to ASHRAE 62.2 (2007 version), which sets minimum ventilation rates for indoor air quality.
| Home Size (sq. ft.) | Required Ventilation Rate (CFM) |
|---|---|
| 1,000 – 1,500 sq. ft. | 45 CFM |
| 1,500 – 2,500 sq. ft. | 60 CFM |
| 2,500 – 3,500 sq. ft | 75 CFM |
| 3,500+ sq. ft. | 90 CFM |
Ventilation rates vary based on occupancy and design. Use ASHRAE 62.2 for precise calculations.
Ventilation System Types Approved in Texas
1. Exhaust-Only Ventilation
🚫 Not recommended for humid Texas climates.
✔ Uses a fan to pull stale air out, relying on natural air leaks for fresh air intake.
✔ Typically implemented using bathroom or kitchen exhaust fans with timers.
🔴 Potential Issues in Texas:
– Pulls in humid outdoor air, increasing moisture risks.
– May create negative pressure, pulling in unfiltered air from attics/crawlspaces.
2. Supply-Only Ventilation
✔ Brings in fresh air via a dedicated fan or connected to the HVAC return duct.
✔ Can be integrated into an air handler to filter and condition incoming air.
✅ Recommended for Texas homes when paired with an outdoor air intake damper to prevent over-ventilation.
✔ Uses both supply and exhaust fans to maintain neutral air pressure
✔ Typically uses Heat Recovery Ventilators (HRVs) or Energy Recovery Ventilators (ERVs).
✔ ERVs help control humidity, making them ideal for hot and humid Texas summers.
✅ Best choice for energy-efficient homes and high-performance buildings.
Texas Compliance Pathways for Ventilation
Texas allows compliance through:
1. Prescriptive Path – Install a system that meets ASHRAE 62.2 rates.
2. Performance Path – Use whole-house energy modeling to show compliance.
3. HERS Index Path – Achieve a HERS rating that meets Texas requirements, including ventilation verification.
📞 888-213-3975 – Local Energy Audits – Schedule an airflow and mechanical ventilation compliance test today!
The ventilation requirements in the 2018 IRC/EICC are based on the details in the 2007 version of ASHRAE standard 62.2.
This standard was used by many low-income energy efficiency programs and voluntary green building programs, as well as the ENERGY STAR New Homes program.
Learn more about this standard in a video course at our YouTube Channel:
