State facts
Idaho: homes, climate zones and who licenses the work
Idaho has 795,000 housing units. 39% were built before 1980, and the median year built is 1991. 72.1% of occupied homes are lived in by their owners.
How old the homes are
Idaho 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 Idaho.
How homes are heated
How homes in Idaho are heated
Main heating fuel, share of about 713,000 occupied homes
- Utility gas 51.6%
- Electricity 35.2%
- Wood 5.4%
- Propane or other tank gas 5.3%
- Fuel oil or kerosene 1.2%
- Other fuel 0.7%
- No fuel used 0.4%
- Solar energy 0.2%
- 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 Idaho's residents divide among them, by the county they live in.
| IECC 2021 zone | Share of residents | Counties |
|---|---|---|
| 5B | 71.6% | 22 |
| 6B | 28.4% | 22 |
ENERGY STAR rates windows, doors and skylights for four climate zones of its own. All of Idaho falls in the Northern zone.
By NOAA's 1991–2020 climate normals, counties here average 143 days a year with a low of 32°F or colder, weighted by where people live. The range runs from 106 days in the mildest county to 242 in the coldest.
Flood risk and flood insurance
0.5% of residential structures in Idaho carry a National Flood Insurance Program policy: 3,768 policies, in FEMA's count as of August 3, 2026.
In FEMA's National Risk Index, none of Idaho's 44 counties rates high or very high for riverine flooding, coastal flooding or hurricanes.
Fire ants and termites
No county in Idaho is inside the federal imported fire ant quarantine.
Who licenses the work in Idaho
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 Individuals who apply pesticides for others hold a Professional Applicator license; since the 2024 rule update, structural and household pest work falls under the Industrial, Institutional, and Structural Pest Control – Non Commodity (IP) category, which replaced the General Pest Control (GP) and Structural Destroying Pest (SP) categories. Agency: Idaho State Department of Agriculture. Look up a license. Who to call about pest control.
- Heating and cooling HVAC contractors, journeymen and apprentices are licensed or registered by the state under Title 54, Chapter 50 of Idaho Code. Agency: Idaho Division of Occupational and Professional Licenses, Heating, Ventilation and Air Conditioning (HVAC) Board. Look up a license. Who to call about heating and cooling.
- Window replacement and other home improvement Contractors must register (not license) with the state for construction jobs over $2,000 in materials and labor unless exempt. Agency: Idaho Division of Occupational and Professional Licenses, Idaho Contractors Board. Look up a license. Who to call about window replacement.
- Mold remediation No statewide license. The state does not regulate mold work; the Department of Health and Welfare says no Idaho law requires mold inspections or sets cleanup standards. 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
- Idaho State Department of Agriculture agri.idaho.gov agri.idaho.gov
- Idaho Division of Occupational and Professional Licenses, Heating, Ventilation and Air Conditioning (HVAC) Board dopl.idaho.gov dopl.idaho.gov
- Idaho Division of Occupational and Professional Licenses, Idaho Contractors Board dopl.idaho.gov dopl.idaho.gov
- healthandwelfare.idaho.gov healthandwelfare.idaho.gov healthandwelfare.idaho.gov
- epa.gov epa.gov epa.gov