The 2009 and 2012 International Energy Conservation Codes (IECC) yield positive benefits for Missouri homeowners. Moving to either the 2009 or 2012 IECC from the 2006 IECC is cost effective over a 30-year life cycle. On average, Missouri homeowners will save $2,229 over 30 years under the 2009 IECC, with savings still higher at $7,826 with the 2012 IECC. After accounting for upfront costs and additional costs financed in the mortgage, homeowners should see net positive cash flows (i.e., cumulative savings exceeding cumulative cash outlays) in 1 year for both the 2009 and 2012 IECC. Average annual energy savings are $143 for the 2009 IECC and $507 for the 2012 IECC.