Energy savings of retrofitting residential buildings with variable air volume systems across different climates

Residential buildings account for 20% of total energy consumption in the United States, with single family detached houses accounting for 77% of residential site energy consumption. A multizone variable air volume (VAV) system can save energy by directing conditioned air to different occupied zones in the home as needed. While multizone VAV systems in single family houses have been economically inaccessible in the past, recent technological developments in building automation controls and the Internet of Things (IoT) can enable homeowners to retrofit their existing HVAC systems into VAV systems, warranting further investigation into the energy savings potential of such systems. Past residential VAV system research mostly involved simulations and measurements of singular case study houses over short periods of time. In this study, representative energy models of two different house sizes, with estimates of individual room sizes, were developed to expand on those case studies and examine energy savings for single family homes across seven US climate zones over an entire year. Average size house models report 24%-42% source energy savings while large house size models report 18%-35% source energy savings, with houses in cooling dominant climate saving relatively more. Annual energy cost savings range from 24% to 42% for average size house models and 18%-35% for large size house models. These results indicate greater energy savings potential for single family homeowners considering VAV retrofits in cooling climates and areas with higher cost of electricity. Projected present value of energy cost savings over a typical home ownership period similarly yielded favorability for houses in cooling dominant climates, but were impacted by energy price changes over time. Future research should focus on the payback analyses of single family VAV system implementations and its sensitivity to occupant behavior. The details of the representative energy models, with estimates of room sizes and occupancy schedules, are provided for future studies that focus on multizone energy saving strategies.