The Northwest Energy Efficiency Alliance (NEEA) contracted with Industrial Economics, Incorporated (IEc) and Resource Refocus to conduct a residential code compliance evaluation in Idaho that examined new construction single family homes built under the International Energy Conservation Code (IECC) 2018 with Idaho amendments. The evaluation looked at whole-home and measure-level compliance with the code, opportunities to increase compliance with the code, and primary space and water heating fuel selection.
From May 2023 to December 2023, IEc collected permit data on 140 homes and conducted on-site audits at 164 homes. Energy modeling analysis conducted by Resource Refocus indicates that 97.8% of homes built under IECC 2018 with Idaho amendments comply with the code and that external wall insulation has the lowest rate of compliance and the highest potential for energy savings if non-compliant homes were brought to code-minimum levels. The study also found that a large majority of homes built under IECC 2018 with Idaho amendments have gas primary space and water heating.