Big Bend: energy calcs & Manual J.
29°F heating design: Florida’s capital region sizes for winter too.
Leon, Gadsden, Jefferson, Wakulla and Liberty counties all use Tallahassee's design limits, 94°F cooling and 29°F heating, a 65-degree swing that makes heating a full design load. Franklin, on the coast, uses Apalachicola's gentler 91°F and 36°F. All six are climate zone 2A, so the energy form baselines match the peninsula's.
- Counties
- 6 countiesLeon, Gadsden, Jefferson, Wakulla, Liberty and Franklin
- 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
Leon, Gadsden, Jefferson, Wakulla, Liberty and Franklin
Per-county table6 counties · zone, design °F, permits, housing
| County · stations | Zone | Design °F | Permits | Median built | Single-family | Mobile | Electric heat |
|---|---|---|---|---|---|---|---|
| LeonTallahassee Regional Airport (Manual J) · Tallahassee Municipalcip (ASHRAE) | 2A | 94° / 29° | 617 #37 | 1989 | 48.7% | 6.9% | 86.8% |
| WakullaTallahassee Regional Airport (Manual J) · Tallahassee Municipalcip (ASHRAE) | 2A | 94° / 29° | 518 #38 | 1998 | 66.6% | 27.3% | 91.9% |
| FranklinApalachicola Municipal (ASHRAE) | 2A | 91° / 36° | 112 #48 | 1988 | 69.2% | 14.9% | 90.7% |
| JeffersonTallahassee Regional Airport (Manual J) · Tallahassee Municipalcip (ASHRAE) | 2A | 94° / 29° | 55 #59 | 1987 | 65.9% | 29.2% | 87.9% |
| GadsdenTallahassee Regional Airport (Manual J) · Tallahassee Municipalcip (ASHRAE) | 2A | 94° / 29° | 44 #61 | 1983 | 64.1% | 26.2% | 84.7% |
| LibertyTallahassee Regional Airport (Manual J) · Tallahassee Municipalcip (ASHRAE) | 2A | 94° / 29° | 25 #65 | 1991 | 59.2% | 37.0% | 93.0% |
What it means for sizing
2 paragraphs · design temperatures, housing stock, equipment
Tallahassee Regional supplies the cooling limit and Tallahassee's municipal record the heating limit for five of these six counties: 94°F and 29°F.2 Apalachicola gives Franklin 91°F and 36°F.2 All are zone 2A.1 A 29°F design means, in our experience, that an undersized heat pump shows up on the coldest mornings as strip heat running for hours, so we report capacity at design in every Big Bend Manual S.
Leon is the region's market, with 617 one-unit permits in 2025, and Wakulla is the growth county, with 518 permits and 6.8% of its housing built in 2020 or later.34 Leon's owner occupancy is low, 52.6%, a university-town profile.4 Bottled gas heats 9.0% of homes in Jefferson, the highest share among all 51 hub counties.4
Worked example
2,000 sq ft house in Leon County → 24,720 Btu/h, 2.06 tons · illustrative
Illustrative · not a Manual J
A 2,000 sq ft frame home at Tallahassee's 94°F and 29°F limits, among the coldest heating designs in our examples; expect the heating line to approach the cooling total.
| House | new single-storey frame home, Tallahassee area |
|---|---|
| Conditioned area | 2,000 sq ft, 1 storey, 9 ft ceilings |
| Bedrooms / occupants | 3 / 4 |
| Glazing | 14% of floor area (280 sq ft), U 0.3, SHGC 0.25 |
| Walls / ceiling | R-13 walls, R-38 ceiling under a vented attic |
| Air leakage | 5 ACH50 |
| Ducts | in the attic, 8% gain allowance |
| Outdoor design | 94°F cooling / 29°F heating (Leon County, sourced) |
| Indoor design | 75°F cooling / 70°F heating |
| Design grains difference | 40 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.
Big Bend questions
3 answers · What design temperatures should a Tallahassee Manual J use?
What design temperatures should a Tallahassee Manual J use?
Leon County's limits are 94°F at 1% cooling, from Tallahassee Regional Airport, and 29°F at 99% heating, from the Tallahassee municipal station, per RESNET's county table. Gadsden, Jefferson, Wakulla and Liberty use the same pair, so a 65-degree design swing applies across most of the Big Bend.
Does a 29°F heating design change heat-pump sizing?
It should change how you check it. At 29°F many heat pumps deliver well under their rated capacity, so Manual S compares output at the design temperature with the heating load and sizes backup heat from the gap. Pick the cooling size from Manual J first, then confirm heating.
Is Wakulla County growing?
By permit numbers, yes. Wakulla issued 518 permits for new single-family units in 2025, 38th in Florida and close to Leon's 617 despite a far smaller base, and 6.8% of its housing units were built in 2020 or later, per the American Community Survey.
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