Smart Ventilation Retrofit Demonstration Project

Indoor Air quality (IAQ) concerns from mechanical ventilation have increased, particularly as construction trends move towards tighter envelopes to increase efficiency. Yet there is a tension between providing ventilation to ensure good IAQ and reducing the energy and demand impacts of this ventilation.  This project investigates “smart ventilation” systems that have sensors to track pollutants and automate ventilation systems to address IAQ. Smart ventilation systems include apps that provide the user with an app-based interface, tracking and logging IAQ, along with run time presented on an easy-to-understand graphic display. Customers can use this feedback to improve the air quality in their home. Smart ventilation is a promising, emerging technology that can provide good IAQ with minimal energy and demand impacts.  To achieve the project objectives, the team installed smart ventilation systems in 17 multifamily dwelling units and collected and compared IAQ and fan energy data for the existing ventilation strategy and the smart ventilation system. They then conducted energy simulations to compare energy use for fan and space conditioning under baseline conditions and smart ventilation system fan operation. Last, the team collected resident feedback on the operation and performance of the smart ventilation system through a survey and evaluated the readiness, use cases, and site requirements for using smart ventilation systems. The results show that smart ventilation systems can maintain acceptable IAQ while reducing ventilation runtime compared to continuously operating systems, provided the underlying ventilation infrastructure is properly designed and functioning. Energy modeling indicated that intermittent, pollutant-based ventilation control can provide substantial energy savings compared to continuously operating ventilation, particularly in climate zones with significant heating or cooling loads. Estimated annual savings ranged from 800 to 1,400 kilowatt-hours per dwelling in cooler or hotter climates and from 450 to 600 kilowatt-hours in milder regions. This research project demonstrated the technical feasibility and energy-saving potential of smart ventilation systems in residential buildings, especially where ventilation systems are capable of maintaining acceptable IAQ. However, successful implementation requires ensuring sufficient ventilation airflow, providing user education, and accounting for climate-specific performance. The team recommends evaluating and correcting ventilation design and airflow issues before retrofitting smart ventilation systems and providing additional user guidance to improve understanding and response to IAQ indicators.  The California Statewide Utilities could consider developing a programmatic offering for smart ventilation systems, but more research is needed to refine energy savings from this measure. In addition, a programmatic offering should require verification of the ventilation system’s airflow rate before installing a smart ventilation system to ensure adequate air flow, as well as testing or manufacturer documentation showing that the smart system reliably operates the ventilation during times when pollutant levels are high.