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Maryland: homes, climate zones and who licenses the work

Maryland has 2.6 million housing units. 51.2% were built before 1980, and the median year built is 1979. 67.6% of occupied homes are lived in by their owners.

How old the homes are

Maryland housing units, by year built

Layers drawn to scale

Maryland housing units by year built 51.2% of Maryland housing units were built before 1980 and 48.8% in 1980 or later. 2020 or later: 1.4%; 2010–2019: 8.1%; 2000–2009: 11.5%; 1990–1999: 13.1%; 1980–1989: 14.8%; 1970–1979: 13.5%; 1960–1969: 11.5%; 1950–1959: 10.5%; 1940–1949: 5.0%; 1939 or earlier: 10.7%. Before 1980 51.2% 1980 or later 48.8% 2020 or later 1.4% 2010–2019 8.1% 2000–2009 11.5% 1990–1999 13.1% 1980–1989 14.8% 1970–1979 13.5% 1960–1969 11.5% 1950–1959 10.5% 1940–1949 5.0% 1939 or earlier 10.7%
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 Maryland.

How homes are heated

How homes in Maryland are heated

Main heating fuel, share of 2.4 million occupied homes

  • Electricity 44.1%
  • Utility gas 43.1%
  • Fuel oil or kerosene 6.6%
  • Propane or other tank gas 3.8%
  • Wood 1.0%
  • No fuel used 0.6%
  • Other fuel 0.5%
  • Solar energy 0.4%
  • 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 Maryland's residents divide among them, by the county they live in.

IECC 2021 zoneShare of residentsCounties
4A98.4%22
5A1.6%2

ENERGY STAR rates windows, doors and skylights for four climate zones of its own. Maryland spans 2: North-Central (98.4% of residents), Northern (1.6% of residents).

By NOAA's 1991–2020 climate normals, counties here average 87 days a year with a low of 32°F or colder, weighted by where people live. The range runs from 52 days in the mildest county to 160 in the coldest.

Flood risk and flood insurance

1.7% of residential structures in Maryland carry a National Flood Insurance Program policy: 33,232 policies, in FEMA's count as of August 3, 2026.

In FEMA's National Risk Index, 4 of 24 counties rate high or very high for riverine flooding; 3 of 24 counties rate high or very high for coastal flooding.

Fire ants and termites

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

Who licenses the work in Maryland

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. Maryland Department of Agriculture, Pesticide Regulation Section mgaleg.maryland.gov mgaleg.maryland.gov
  11. Maryland Department of Agriculture, Pesticide Regulation Section onestop.md.gov onestop.md.gov
  12. Maryland Department of Agriculture, Pesticide Regulation Section npic.orst.edu npic.orst.edu
  13. Maryland Board of Heating, Ventilation, Air Conditioning and Refrigeration Contractors (Maryland Department of Labor) labor.maryland.gov labor.maryland.gov
  14. Maryland Home Improvement Commission (Maryland Department of Labor) labor.maryland.gov labor.maryland.gov
  15. Maryland Home Improvement Commission (Maryland Department of Labor) labor.maryland.gov labor.maryland.gov
  16. labor.maryland.gov labor.maryland.gov labor.maryland.gov
  17. epa.gov epa.gov epa.gov