EETD researchers have contributed a series of findings to the new Alternative Calculation Method (ACM) used in Title 24, California's building code. The ACM, the primary design method for new homes, allows designers trade-offs to achieve levels of energy efficiency in flexible ways.
The research shows that lower duct efficiency defaults provide incentives within the standard for designers to provide a more efficient duct system. As a result of LBNL research that measured duct-sealant longevity, the new ACM does not allow thermal distribution credit if duct tape is used as the primary sealant.
An important barrier to increased duct or envelope tightness levels had been the concern that indoor air quality could be compromised at the expense of energy efficiency. To assure minimum ventilation rates in buildings, Division researchers worked with the California Energy Commission to incorporate ASHRAE Standard 62-89 (Ventilation for Acceptable Indoor Air Quality) into the code in an energy-efficient manner.