Denver IECC 2018 Energy Code Rescheck, Colorado Rescheck. The switch from IECC 2015 to 2018 is happening now for Denver’s Rescheck systems. Find out the implications here. Denver IECC 2015 rescheck, denver iecc 2018 rescheck, iecc 2018 rescheck, Rescheck 2018, colorado rescheck, boulder rescheck, littleton rescheck, garrison county rescheck, colorado springs rescheck.