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Residential Indoor Air Quality and Ventilation

Indoor Air Quality and Ventilation

Codes and Standards Enhancement (CASE) Report

The Statewide CASE Team 2019 Title 24, Part 6 Final CASE Report is available below. The Final CASE Report incorporates feedback received during utility-sponsored stakeholder meetings, Energy Commission Pre-Rulemaking workshops, and personal communication with stakeholders. We encourage stakeholders to email feedback on the Final CASE Report to You can also participate in the 2019 Title 24, Part 6 Standards updated by attending the Energy Commission workshops and submitting written comments to the rulemaking docket. Refer to the Pre-Rulemaking and Rulemaking Workshop Notices for instructions on how to submit comments to the Energy Commission’s docket (available here).

Final CASE Report: Residential Indoor Air Quality

Draft CASE Report: Residential Indoor Air Quality

Measure Description

The most significant proposed change to the 2016 Title 24, Part 6 Residential Standards is the adoption of the 2016 version of ASHRAE Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings. The 2016 ASHRAE Standard 62.2 version replaces the California version of ASHRAE Standard 62.2-2010 (which includes Addenda b, c, e, g, h, i, j, l, and n) that was adopted by the 2016 Title 24 Building Energy Efficiency Standards (BEES). The 2016 version includes high-rise multifamily (HRMF) buildings, which were formerly covered by the commercial ventilation standard, ASHRAE 62.1. The following impacts result from the adoption of ASHRAE 62.2-2016, as well as other proposed measures that are designed to enforce and complement the provisions of the ASHRAE ventilation standard:

  • Increases single family residential ventilation rates by an average of 51 percent for the 2,100 square foot prototype and 41 percent for the 2,700 square foot prototype (see Figure 1)
  • Moves coverage of high-rise residential from ASHRAE 62.1 to ASHRAE 62.2, which decreases HRMF building ventilation rates by approximately 30 percent, depending on unit configuration
  • Provides for fine particulate matter (PM2.5) filtration of outside air in locations with high levels of fine particulate matter (PM2.5) concentrations
  • Requires an increase to the filter efficiency requirement listed in Section 6.7 of ASHRAE 62.2-2016 of from MERV* 6 to MERV 13 to reduce indoor levels of PM2.5**
  • Requires HERS verification that kitchen hoods in all dwelling unit types are Home Ventilating Institute (HVI) certified to meet ASHRAE 62.2 requirements for air volume, and sound ratings, and that they are externally vented
  • Requires sealing of multifamily units to improve compartmentalization and verification of leakage rates
  • For HRMF, requires a make-up air source for all units, and prohibits the use of passive vents in areas of high ambient PM2.5
  • Provides for verification that central exhaust shafts and ducts in HRMF buildings are sealed to limit air leakage.
  • Limits the use of indoor air being used as combustion air for space thermal conditioning, water heating and pool heating equipment.

These measures are intended to protect public health by providing a high level of indoor air quality (IAQ) while other Title 24, Part 6 requirements call for homes to be built with improved insulation and lower air leakage.

*MERV is Minimum Efficiency Reporting Value

**Pertains to Mechanical systems that supply air to an occupiable space through ductwork exceeding 10 feet in length and through a thermal conditioning component, except evaporative coolers. It is also referenced in Title 24 Part 6 Section 150(m)12.

California Statewide Utility Codes and Standards Program

This program is funded by California utility customers and administered by Pacific Gas and Electric Company, Southern California Edison, San Diego Gas and Electric Company, Southern California Gas Company, Sacramento Municipal District, and Los Angeles Department of Water and Power in preparation for the California Energy Commission’s Codes and Standards Buildings Advocacy.