Zone 2A covers 239 counties in 7 states, home to about 42,105,522 people (FEMA NRI population). ENERGY STAR’s target for an uninsulated attic here is R49; with 3–4 inches already in place, add to R38.
Insulation targets for zone 2A
| Where | Guidance |
|---|
| Attic, uninsulated | R49 |
| Attic, 3–4 inches already | R38 |
| Floor over unheated space | R13 |
| Walls | No added exterior sheathing listed for zones 1–2; insulate empty wall cavities when siding is off. |
| Basement or crawlspace walls | No basement or crawlspace wall value listed for zones 1–2. |
Homeowner retrofit guidance, not your local code. Your jurisdiction may enforce an older or amended IECC; ask the building department before a permit job.
What it means for upkeep
Most zone 2A counties fall in the hot-humid Building America region. Long cooling season, heavy humidity and the Atlantic hurricane season set the calendar: drains, dehumidifying and storm prep.
The “A” (moist) regime means humidity drives much of the care: drains, dehumidifying and keeping crawlspaces and basements dry.
See this month’s tasks for the hot-humid region.
Largest counties in zone 2A
Harris County, TX4,726,200Dallas County, TX2,607,218Tarrant County, TX2,106,939Bexar County, TX2,007,298Hillsborough County, FL1,458,282Orange County, FL1,428,790Travis County, TX1,285,769Duval County, FL994,675Pinellas County, FL958,822Fort Bend County, TX822,581Lee County, FL759,922Polk County, FL721,918Montgomery County, TX620,016Williamson County, TX608,015Brevard County, FL606,067Pasco County, FL561,566Volusia County, FL551,829Seminole County, FL470,586East Baton Rouge Parish, LA456,512Jefferson Parish, LA440,590Sarasota County, FL433,908Mobile County, AL414,514Manatee County, FL399,485Osceola County, FL387,795Orleans Parish, LA383,606Lake County, FL383,042Marion County, FL375,566Collier County, FL375,443Brazoria County, TX371,474Bell County, TX369,846Nueces County, TX352,623Galveston County, TX350,477St. Lucie County, FL328,876Escambia County, FL321,367Chatham County, GA293,520Leon County, FL292,157Alachua County, FL277,984St. Johns County, FL273,175St. Tammany Parish, LA263,870McLennan County, TX260,302Jefferson County, TX256,386Lafayette Parish, LA241,618Hays County, TX240,800Brazos County, TX233,555Baldwin County, AL231,365Clay County, FL218,078Calcasieu Parish, LA216,652Okaloosa County, FL211,293Harrison County, MS208,275Hernando County, FL194,448Ellis County, TX192,122Santa Rosa County, FL187,714Charlotte County, FL186,734Beaufort County, SC186,606Johnson County, TX179,719Bay County, FL174,869Guadalupe County, TX172,522Comal County, TX161,300Martin County, FL158,246 States in this zone: Texas (81), Florida (63), Georgia (41), Louisiana (37), Alabama (9), Mississippi (6), South Carolina (2).