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Arizona: homes, climate zones and who licenses the work

Arizona has 3.2 million housing units. 29.3% were built before 1980, and the median year built is 1992. 67.4% of occupied homes are lived in by their owners.

How old the homes are

Arizona housing units, by year built

Layers drawn to scale

Arizona housing units by year built 29.3% of Arizona housing units were built before 1980 and 70.7% in 1980 or later. 2020 or later: 2.8%; 2010–2019: 11.6%; 2000–2009: 22.4%; 1990–1999: 17.4%; 1980–1989: 16.5%; 1970–1979: 15.2%; 1960–1969: 6.3%; 1950–1959: 4.9%; 1940–1949: 1.5%; 1939 or earlier: 1.4%. Before 1980 29.3% 1980 or later 70.7% 2020 or later 2.8% 2010–2019 11.6% 2000–2009 22.4% 1990–1999 17.4% 1980–1989 16.5% 1970–1979 15.2% 1960–1969 6.3% 1950–1959 4.9% 1940–1949 1.5% 1939 or earlier 1.4%
Source: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, tables B25034, B25035 and B25003; heating fuel below from B25040.

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 Arizona.

How homes are heated

How homes in Arizona are heated

Main heating fuel, share of 2.9 million occupied homes

  • Electricity 59.9%
  • Utility gas 33.3%
  • Propane or other tank gas 2.8%
  • Wood 1.6%
  • Solar energy 1.0%
  • No fuel used 1.0%
  • Other fuel 0.3%
  • Fuel oil or kerosene 0.1%
  • Coal or coke <0.1%
Source: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates, table B25040 (occupied housing units).

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 Arizona's residents divide among them, by the county they live in.

IECC 2021 zoneShare of residentsCounties
2B85.5%5
3B6%5
5B4.4%3
4B4.1%2

ENERGY STAR rates windows, doors and skylights for four climate zones of its own. Arizona spans 4: Southern (85.5% of residents), South-Central (6% of residents), Northern (4.4% of residents), North-Central (4.1% of residents).

By NOAA's 1991–2020 climate normals, counties here average 28 days a year with a low of 32°F or colder, weighted by where people live. The range runs from 7 days in the mildest county to 172 in the coldest.

Flood risk and flood insurance

0.7% of residential structures in Arizona carry a National Flood Insurance Program policy: 17,476 policies, in FEMA's count as of August 3, 2026.

In FEMA's National Risk Index, 7 of 15 counties rate high or very high for riverine flooding.

Fire ants and termites

No county in Arizona is inside the federal imported fire ant quarantine.

Who licenses the work in Arizona

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.

Checked 2026-09-29. Licensing rules change; the agency's own page is the authority.

Sources

  1. U.S. Census Bureau American Community Survey 2020–2024 5-year estimates, tables B25034, B25035, B25040 and B25003 data.census.gov
  2. Pacific Northwest National Laboratory Guide to Determining Climate Zone by County: Building America and IECC 2021 Updates basc.pnnl.gov
  3. U.S. Department of Energy Prototype Building Models (climate zones 1–8 and moisture regimes A, B, C) energycodes.gov
  4. ENERGY STAR Climate zones by county for windows, doors and skylights energystar.gov
  5. NOAA National Centers for Environmental Information U.S. Climate Normals 1991–2020, annual and seasonal ncei.noaa.gov
  6. Federal Emergency Management Agency OpenFEMA NFIP Residential Penetration Rates (as of 2026-08-03) fema.gov
  7. Federal Emergency Management Agency National Risk Index, county ratings fema.gov
  8. USDA Animal and Plant Health Inspection Service Imported fire ant quarantine map aphis.usda.gov
  9. Electronic Code of Federal Regulations 7 CFR part 301, subpart P, Imported Fire Ant ecfr.gov
  10. Arizona Department of Agriculture, Pest Management Division agriculture.az.gov agriculture.az.gov
  11. Arizona Department of Agriculture, Pest Management Division azleg.gov azleg.gov
  12. Arizona Department of Agriculture, Pest Management Division azleg.gov azleg.gov
  13. Arizona Department of Agriculture, Pest Management Division azleg.gov azleg.gov
  14. Arizona Department of Agriculture, Pest Management Division azleg.gov azleg.gov
  15. Arizona Registrar of Contractors roc.az.gov roc.az.gov
  16. Arizona Registrar of Contractors azleg.gov azleg.gov
  17. Arizona Registrar of Contractors azleg.gov azleg.gov
  18. Arizona Registrar of Contractors azleg.gov azleg.gov
  19. epa.gov epa.gov epa.gov