According to the Department of Energy, Michigan will be the fifth state to adopt the 2015 International Energy Conservation Code (IECC), with "amendments, deletions, and additions deemed necessary for use in Michigan." For now, this only affects new residential construction and significant renovations, without requiring unaltered building systems to comply. Michigan's new energy code requires less than 4 ACH and <4% duct leakage per 100 sf. of conditioned space with testing, "conducted by an approved third party."
As expected a RESNET HERS® Index will be accepted to show compliance. The minimum Energy Rating Index scores are:
Click here to download a copy of "Part 10 - Michigan Energy Code."