Central Panhandle: energy calcs & Manual J.
From Cape San Blas’s 86°F to Holmes County’s 94°F.
The Central Panhandle spans Florida's widest range of cooling design limits: 86°F in Gulf County, from Cape San Blas, up to 94°F in Holmes. Heating limits run from 40°F on the coast to 30°F inland. All six counties are climate zone 2A, and Bay County issued 1,685 single-family permits in 2025, most in the group.
- Counties
- 6 countiesBay, Gulf, Calhoun, Jackson, Holmes and Washington
- Departments
- Each county’s ownSeveral cities run their own · what we publish
- Code edition
- FBC Energy Conservation, 8th Ed. (2023)9th Ed. (2026) scheduled for Dec 31, 2026 · what changes
- Price
- $195 · $445 · $595Energy calc from · full package · sealed. Same in all 67 counties · price list
- Ready by
- 2–3 business daysExpedited: within 24 business hours, +$150. Clock starts when complete plans pass intake (3:00 PM ET cutoff) · how it works
Bay, Gulf, Calhoun, Jackson, Holmes and Washington
Per-county table6 counties · zone, design °F, permits, housing
| County · stations | Zone | Design °F | Permits | Median built | Single-family | Mobile | Electric heat |
|---|---|---|---|---|---|---|---|
| BayPanama City Bay County (ASHRAE) · Tyndall AFB (ASHRAE) | 2A | 91° / 36° | 1,685 #25 | 1993 | 51.0% | 10.0% | 87.4% |
| GulfCape San Blas (Manual J) | 2A | 86° / 40° | 302 #40 | 1995 | 65.9% | 17.9% | 81.8% |
| WashingtonPanama City Bay County (ASHRAE) · Marianna Municipal (ASHRAE) | 2A | 91° / 30° | 223 #43 | 1990 | 57.5% | 36.7% | 88.3% |
| JacksonMarianna Municipal (ASHRAE) | 2A | 93° / 30° | 96 #51 | 1983 | 65.4% | 27.7% | 90.9% |
| HolmesCairns AAF, AL (ASHRAE) | 2A | 94° / 30° | 12 #66 | 1983 | 59.0% | 36.0% | 90.8% |
| CalhounMarianna Municipal (ASHRAE) | 2A | 93° / 30° | 4 #67 | 1986 | 59.3% | 34.3% | 88.1% |
What it means for sizing
2 paragraphs · design temperatures, housing stock, equipment
Gulf County's 86°F cooling limit, from Cape San Blas, is the lowest assigned to any Florida county; Holmes, using an Alabama station, reaches 94°F.2 Bay draws on Panama City and Tyndall (91°F, 36°F), Calhoun and Jackson on Marianna (93°F, 30°F), and Washington splits between Panama City and Marianna (91°F, 30°F).2 All six are zone 2A.1
Bay dominates construction, with 1,685 one-unit permits in 2025; Calhoun issued 4.3 Inland counties have old housing, with Jackson and Holmes medians of 1983 and about 45% of units pre-1980.4 An eight-degree spread in cooling design within one region is, in our view, a good reason never to reuse a Panama City Manual J for a Marianna house.
Worked example
1,900 sq ft house in Bay County → 25,130 Btu/h, 2.09 tons · illustrative
Illustrative · not a Manual J
A 1,900 sq ft block home at Bay's 91°F and 36°F limits; Bay's rooms median is 5.0.4 Rerun it at Holmes's 94°F and 30°F and both lines grow.
| House | new single-storey block home, Panama City area |
|---|---|
| Conditioned area | 1,900 sq ft, 1 storey, 9 ft ceilings |
| Bedrooms / occupants | 3 / 4 |
| Glazing | 14% of floor area (266 sq ft), U 0.32, SHGC 0.25 |
| Walls / ceiling | R-7.8 walls, R-38 ceiling under a vented attic |
| Air leakage | 5 ACH50 |
| Ducts | in the attic, 8% gain allowance |
| Outdoor design | 91°F cooling / 36°F heating (Bay County, sourced) |
| Indoor design | 75°F cooling / 70°F heating |
| Design grains difference | 45 gr/lb (assumption) |
Illustrative only. A simplified block-load estimate with the inputs shown, not an ACCA Manual J, and not for permitting. A real calc goes room by room with your plans, orientation and equipment data.
Building departments
How we publish department checklists
Every county here has its own building department, and several cities run their own. We publish a department's checklist, contacts and quirks only after reading them on its official page, and each county here gets its own page once that's done. Until then, check with the county building department before you submit. Ordering works statewide today.
Central Panhandle questions
3 answers · Why is Gulf County's cooling design temperature so low?
Why is Gulf County's cooling design temperature so low?
Gulf County's 86°F limit comes from the Cape San Blas station, which RESNET assigns to the whole county; a coastal peninsula site runs cooler than inland airports. It's the lowest cooling limit for any Florida county. A house inland near Wewahitchka still uses 86°F under that table.
What design temperatures apply in Marianna?
Jackson County uses the Marianna Municipal station: 93°F at 1% cooling and 30°F at 99% heating. Calhoun County takes the same values. At 30°F, size heat-pump backup heat from capacity at the design temperature rather than from the rated output.
Is the Central Panhandle in climate zone 1 or 2?
All six counties, Bay, Gulf, Calhoun, Jackson, Holmes and Washington, are climate zone 2A, marked warm-humid, in Table R301.1 of the 8th Edition energy code. Zone 1A is limited to seven South Florida counties, so Panhandle energy forms use zone 2 prescriptive baselines.
Nearby and related
Price
One statewide price in all 67 counties. Building departments decide what they accept; we don’t guarantee approval. Revisions for plan-review comments on the same design are free.
Sources
4 primary references · numbered to match the citations
- 012023 Florida Building Code, Energy Conservation (8th Ed.), Table R301.1, climate zones by countyup.codes
- 02RESNET / ENERGY STAR, Appendix A: HVAC Design Temperature Limits by State and County (v4, 2019)resnet.us
- 03U.S. Census Bureau, Building Permits Survey, 2025 annual county data (new privately-owned 1-unit housing units)www2.census.gov
- 04U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates (B25001, B25003, B25018, B25024, B25034, B25035, B25040), via Census Reportercensusreporter.org