District of Columbia Building Climate Zone
Washington, DC is a mixed humid Zone 4 planning case. State-level climate-zone pages are planning baselines; IECC climate zones are county based.
Planning baseline
- IECC climate zone: Zone 4A
- Climate type: Mixed
- Wall planning target: R-20 + R-5 continuous insulation or R-13 + R-10 continuous insulation
- Attic planning target: R-60
- Floor planning target: R-19, or R-30 in Marine 4