State facts
District of Columbia: homes, climate zones and who licenses the work
The District of Columbia has 361,000 housing units. 69% were built before 1980, and the median year built is 1958. 41.5% of occupied homes are lived in by their owners.
How old the homes are
District of Columbia 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 the District of Columbia.
How homes are heated
How homes in the District of Columbia are heated
Main heating fuel, share of about 324,000 occupied homes
- Utility gas 47.9%
- Electricity 46.9%
- No fuel used 2.0%
- Propane or other tank gas 1.1%
- Fuel oil or kerosene 0.9%
- Other fuel 0.7%
- Solar energy 0.3%
- Coal or coke <0.1%
- Wood <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. The District of Columbia is in zone 4A.
ENERGY STAR rates windows, doors and skylights for four climate zones of its own. All of the District of Columbia falls in the North-Central zone.
By NOAA's 1991–2020 climate normals, the District of Columbia averages 84 days a year with a low of 32°F or colder.
Flood risk and flood insurance
1.1% of residential structures in the District of Columbia carry a National Flood Insurance Program policy: 1,443 policies, in FEMA's count as of August 3, 2026.
FEMA's National Risk Index rates the District of Columbia high or very high for riverine flooding and hurricanes.
Fire ants and termites
The District of Columbia is not inside the federal imported fire ant quarantine.
Who licenses the work in District of Columbia
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 Every business that advertises or does pest control in the District must be licensed: the company holds a Pesticide Operator's License and its applicators are certified by DOEE and hold Certified Pesticide Applicator licenses. Agency: District of Columbia Department of Energy and Environment. Look up a license. Who to call about pest control.
- Heating and cooling Refrigeration and air conditioning mechanics are licensed by the District's Board of Industrial Trades. Agency: District of Columbia Department of Licensing and Consumer Protection, Board of Industrial Trades. Look up a license. Who to call about heating and cooling.
- Window replacement and other home improvement Home improvement contractors hold a Basic Business License in the Home Improvement Contractor category, which requires insurance, a criminal history report and a $25,000 surety bond. Agency: District of Columbia Department of Licensing and Consumer Protection. Look up a license. Who to call about window replacement.
- Mold remediation Mold assessors and mold remediators must hold a DOEE license, which requires passing a DOEE-approved exam and is valid for two years. Agency: District of Columbia Department of Energy and Environment. Look up a license. 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
- District of Columbia Department of Energy and Environment doee.dc.gov doee.dc.gov
- District of Columbia Department of Energy and Environment doee.dc.gov doee.dc.gov
- District of Columbia Department of Licensing and Consumer Protection, Board of Industrial Trades dlcp.dc.gov dlcp.dc.gov
- District of Columbia Department of Licensing and Consumer Protection dlcp.dc.gov dlcp.dc.gov
- District of Columbia Department of Energy and Environment doee.dc.gov doee.dc.gov
- District of Columbia Department of Energy and Environment doee.dc.gov doee.dc.gov
- epa.gov epa.gov epa.gov