This project investigated the potential of using smart ventilation technology to reduce ventilation-related energy use, while maintaining indoor air quality, in new high-performance California homes. Evaluation criteria included annual ventilation-related energy, peak energy and time-of-use savings, and the indoor air quality relative to a minimally code-compliant ventilation system. The project’s simulation approach used CONTAM’s air flow and contaminant transport model, combined with the EnergyPlus building loads model, to investigate the ventilation, indoor air quality, and energy dynamics in homes. The project investigated house types representing the default California Building Energy Efficiency Standards-compliant homes for four varying California climate zones. Single-zone ventilation approaches showed that controls that vary ventilation depending on outdoor temperatures have the ability to consistently save half of ventilation-related energy without compromising long-term indoor air quality. Because this work included contaminants, such as formaldehyde, from building materials and furnishings, focusing ventilation on occupied times did not save much energy unless additional measures were taken — such as one-hour pre-occupancy ventilation. Multizone ventilation approaches showed little potential for additional energy improvements, with indoor air quality impacts dependent on the particular contaminant of interest. Controls that directly sensed contaminants and controlled them to acceptable levels showed that the very low limit in California for formaldehyde resulted in continuous ventilation operation with no energy savings but substantial reductions in contaminants. In summary, these advanced smart ventilation controls have shown the potential to reduce energy use by at least half for a broad range of both new and existing California homes in varying climates using controls that are simple and inexpensive to implement and that little is to be gained from zoned ventilation or direct contaminant control.
Author(s)
Iain Walker, Brennan Less, Spencer Dutton, David Lorenzetti, Mike Sohn
