State facts
Michigan: homes, climate zones and who licenses the work
Michigan has 4.6 million housing units. 62.1% were built before 1980, and the median year built is 1972. 73.2% of occupied homes are lived in by their owners.
How old the homes are
Michigan housing units, by year built
Layers drawn to scale
Age changes what applies to a house. In general, anyone paid to do work that disturbs painted surfaces in a home built before 1978 must be certified in lead-safe work practices under the EPA's Renovation, Repair and Painting Rule, which the EPA administers directly in Michigan.
How homes are heated
How homes in Michigan are heated
Main heating fuel, share of 4.1 million occupied homes
- Utility gas 74.9%
- Electricity 12.1%
- Propane or other tank gas 8.7%
- Wood 2.2%
- Fuel oil or kerosene 0.8%
- Other fuel 0.8%
- No fuel used 0.5%
- Solar energy <0.1%
- Coal or coke <0.1%
Climate and building zones
The 2021 International Energy Conservation Code assigns every county a climate zone from 1 to 8 and a moisture regime: A for moist, B for dry, C for marine. Zones 7 and 8 have no letter. Here is how Michigan's residents divide among them, by the county they live in.
| IECC 2021 zone | Share of residents | Counties |
|---|---|---|
| 5A | 88.7% | 37 |
| 6A | 10.6% | 44 |
| 7 | 0.7% | 2 |
ENERGY STAR rates windows, doors and skylights for four climate zones of its own. All of Michigan falls in the Northern zone.
By NOAA's 1991–2020 climate normals, counties here average 141 days a year with a low of 32°F or colder, weighted by where people live. The range runs from 108 days in the mildest county to 203 in the coldest.
- SEER2 Requirements by State: What a New AC Must Meet
- What Size AC Do I Need? How a Load Calculation Answers It
- Do Heat Pumps Work in Cold Weather? What to Check Before Buying
- No Heat in Winter: How to Stay Safe Until the Furnace Is Fixed
- Ice Dams: Why They Leak Into Ceilings and How to Stop Them
- Crawl Space Moisture: Vented vs. Sealed Crawl Spaces
- Condensation on the Inside of Windows: Causes and Fixes
Flood risk and flood insurance
0.4% of residential structures in Michigan carry a National Flood Insurance Program policy: 16,036 policies, in FEMA's count as of August 3, 2026.
In FEMA's National Risk Index, 4 of 83 counties rate high or very high for riverine flooding.
Fire ants and termites
No county in Michigan is inside the federal imported fire ant quarantine.
Who licenses the work in Michigan
Before anyone starts work, check the license with the agency below. Where the state does not license a trade, cities and counties may; ask the one where the house is.
- Pest control Firms that apply pesticides for hire hold a pesticide application business license, and the applicators who work for them must be certified applicators or registered technicians in the business's license categories, including structural wood-destroying pest work. Agency: Michigan Department of Agriculture and Rural Development, Pesticide and Plant Pest Management Division. Look up a license. Who to call about pest control.
- Heating and cooling Mechanical contractors hold a state license in specific work classifications, such as limited or unlimited refrigeration and air conditioning service, and must pass an exam for each classification. Agency: Michigan Department of Licensing and Regulatory Affairs, Bureau of Construction Codes. Look up a license. Who to call about heating and cooling.
- Window replacement and other home improvement People who repair, alter or improve a residential structure for pay are licensed as residential builders or as maintenance and alteration contractors in specific trades (such as carpentry, siding, and screens and storm sash). Agency: Michigan Department of Licensing and Regulatory Affairs, Bureau of Construction Codes. Look up a license. Who to call about window replacement.
- Mold remediation No statewide license. The State of Michigan does not certify mold remediators or mold testing companies. Who to call about water damage and mold.
Checked 2026-09-29. Licensing rules change; the agency's own page is the authority.
Sources
- U.S. Census Bureau American Community Survey 2020–2024 5-year estimates, tables B25034, B25035, B25040 and B25003 data.census.gov
- Pacific Northwest National Laboratory Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates basc.pnnl.gov
- U.S. Department of Energy Prototype Building Models (climate zones 1–8 and moisture regimes A, B, C) energycodes.gov
- ENERGY STAR Climate zones by county for windows, doors and skylights energystar.gov
- NOAA National Centers for Environmental Information U.S. Climate Normals 1991–2020, annual and seasonal ncei.noaa.gov
- Federal Emergency Management Agency OpenFEMA NFIP Residential Penetration Rates (as of 2026-08-03) fema.gov
- Federal Emergency Management Agency National Risk Index, county ratings fema.gov
- USDA Animal and Plant Health Inspection Service Imported fire ant quarantine map aphis.usda.gov
- Electronic Code of Federal Regulations 7 CFR part 301, subpart P, Imported Fire Ant ecfr.gov
- Michigan Department of Agriculture and Rural Development, Pesticide and Plant Pest Management Division michigan.gov michigan.gov
- Michigan Department of Agriculture and Rural Development, Pesticide and Plant Pest Management Division michigan.gov michigan.gov
- Michigan Department of Agriculture and Rural Development, Pesticide and Plant Pest Management Division npic.orst.edu npic.orst.edu
- Michigan Department of Licensing and Regulatory Affairs, Bureau of Construction Codes michigan.gov michigan.gov
- Michigan Department of Licensing and Regulatory Affairs, Bureau of Construction Codes michigan.gov michigan.gov
- Michigan Department of Licensing and Regulatory Affairs, Bureau of Construction Codes michigan.gov michigan.gov
- Michigan Department of Licensing and Regulatory Affairs, Bureau of Construction Codes michigan.gov michigan.gov
- michigan.gov michigan.gov michigan.gov
- epa.gov epa.gov epa.gov