Towards Net-Zero Energy Consumption with Near Net-Zero Initial Cost: A Case Study from Georgia, USA

Abstract

This research presents a case study of a single-family home in Georgia, United States, that achieves near net-zero energy costs for the heating, ventilation, and air conditioning (HVAC) system with near-zero additional capital investment. Building information modeling (BIM), energy analysis, and practical common construction practices were integrated to trade-off between design and construction alternatives to achieve these results. An accelerated number of publications addressed net-zero energy buildings (NZEB). Much of this research addresses means and methods to make buildings produce as much energy as they consume (net-zero site or building energy) or make buildings produce energy and sell it to offset the buildings’ energy bills (net-zero cost). However, NZEBs still constitute a small fraction of the building industry, which is mainly due to higher initial costs, significant deviations from common construction practices, or altering common building operations and comfort levels. In this research, a practical approach for achieving NZEB was tested and used in constructing a single-family home. BIM software that generates annual energy consumption with every design alternative was used during the design and construction phases of this home. The BIM model was also used to generate building materials quantities to estimate the initial construction cost. In this case study, the initial construction cost of the selected design was less than that of comparable homes in the same area. The post-occupancy evaluation showed that the annual energy consumption related to heating and cooling was 72% less than that of comparable homes in the same area. Energy consumption related to hot water consumption was 21% less, and energy consumption for lighting was reduced by 22%. In conclusion, general design guidelines and lessons learned are established to help the residential building industry adopt energy-efficient design and construction approaches to reduce energy consumption in homes without increasing the listed prices of homes.