Nonresidential HVAC Controls

Measure Description

VAV Deadband Airflow

This measure incorporates changes to the variable air volume (VAV) deadband operation that aligns with recent changes in ASHRAE’s Standard 90.1 (2019). The new standards would save energy and simplify compliance by removing a 20 percent airflow requirement for deadband airflow operation and instead only require airflow requirements meet Section 120.1 (c)3. The proposed code changes would remove the existing prescriptive requirements in Section 140.4 and impact both new and existing buildings which utilize VAV HVAC systems.

Expand Economizer Requirements

This measure would modify the existing prescriptive requirements for economizers by including economizers on smaller capacity units with corresponding requirements for fault detection diagnostics (FDD). Economizers are a proven measure in California and save energy by taking advantage of the mild California climate to increasing the amount of free cooling. The proposed code changes would modify existing prescriptive sections to Section 140.4 for applicable nonresidential HVAC equipment.

Dedicated Outdoor Air Systems (DOAS)

Dedicated outdoor air systems (DOAS) have high potential to reduce HVAC energy usage in nonresidential buildings and are also a key solution for all-electric buildings. They are used in a majority of California nonresidential net zero energy projects. Also, DOAS are become increasingly popular in California and nationwide because they offer more flexibility for designers and building owners. Title 24, Part 6 does not currently have a clear definition or prescriptive requirements for DOAS. The proposed code changes would generate cost-effective energy savings, help protect consumers, and support state goals to move towards carbon neutral buildings. The proposed code changes would add a prescriptive section to Section 140.4 specifically for all nonresidential DOAS.

Exhaust Air Heat Recovery

This measure would implement new requirements for exhaust air heat recovery for systems that meet criteria of outdoor air fraction, climate zone, design flow rate, and hours of operation. The requirements are designed based on similar requirements from Section 6.5.6 of ASHRAE Standard 90.1 (2019) which has included requirements for Exhaust Air Heat Recovery since 2004. The requirements partially align with standard 90.1 but have been updated to be applicable for California’s climates and the state of the market.

Submeasures Moved to Future Code Cycles

The Statewide CASE Team is no longer pursuing the proposed changes listed below as it was determined that they did not meet the Energy Commission’s requirements for market readiness, technical feasibility, cost-effectiveness, or enforceability at the time they were considered.

Guest Room Controls

This measure proposes to require ventilation to be shut off to the guest room within 5 minutes of all occupants leaving the room, and require temperature setpoints of at least 60°F for heating and 80°F for cooling for unrented and unoccupied guest rooms. These requirements would align Title 24 Part 6 with the guest room ventilation control requirements in ASHRAE Standard 90.1 (2016) and guestroom purge requirements of 189.1 (2017).

To support ongoing research and future code cycle consideration, additional information on nonresidential thermal bridging can be submitted to the Statewide CASE Team through info@title24stakeholders.com. Materials that the Statewide CASE Team developed when investigating this code change for the 2022 code cycle will be moved to the Future Code Cycles section of this website. Follow this link to find materials on guest room controls.

Relevant Documents

Measure proposals, supporting documents, and other outside references will be made public as they become available.

CASE Reports

• Draft CASE Report Now Available

Round Two Utility-Sponsored Stakeholder Meeting Materials

• Nonresidential HVAC Controls Submeasure Summary (Updated 4/10/2020)
• Presentation – April 14 – Nonresidential and Single Family Part 2
• Notes – April 14 – Nonresidential and Single Family Part 2

Round One Utility-Sponsored Stakeholder Meeting Materials

Submeasure Summaries

• Nonresidential HVAC Controls Submeasure Summary (Updated 4/10/2020)
• Updated Economizer Requirements Submeasure Summary 9-27-2019
• Nonresidential HVAC VAV Minimum Airflow Submeasure Summary 9-6-2019
• Nonresidential HVAC Dedicated Outside Air Systems Submeasure Summary 9-12-2019

Utility-Sponsored Stakeholder Meeting Presentations

• Presentation – Oct. 15 – Nonresidential HVAC Part 1 Utility-Sponsored Stakeholder Meeting
• Presentation – Nov 5th – Nonresidential HVAC and Envelope Part 2 Utility-Sponsored Stakeholder Meeting

Utility-Sponsored Stakeholder Meeting Notes

• Notes – Oct. 15 – Nonresidential HVAC Part 1 Utility-Sponsored Stakeholder Meeting
• Notes – Nov 5th – Nonresidential HVAC and Envelope Part 2