North Central: energy calcs & Manual J.
Eleven counties, 30–33°F winters, and propane in the mix.
North Central Florida's eleven counties share climate zone 2A and some of the state's coldest heating design limits: 30°F in Gilchrist, Dixie, Lafayette, Suwannee and Taylor, 31°F in Hamilton and Madison, and 33°F around Gainesville. Cooling limits run 91–94°F. Propane heats up to 8.5% of homes in some counties, so check the fuel before Manual S.
- Counties
- 11 countiesAlachua, Bradford, Columbia, Gilchrist, Dixie, Lafayette, Suwannee, Union, Hamilton, Madison and Taylor
- 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
Alachua, Bradford, Columbia, Gilchrist, Dixie, Lafayette, Suwannee, Union, Hamilton, Madison and Taylor
Per-county table11 counties · zone, design °F, permits, housing
| County · stations | Zone | Design °F | Permits | Median built | Single-family | Mobile | Electric heat |
|---|---|---|---|---|---|---|---|
| AlachuaGainesville Regional Airport (Manual J) | 2A | 92° / 33° | 689 #36 | 1988 | 50.3% | 6.3% | 78.2% |
| ColumbiaGainesville Regional Airport (Manual J) | 2A | 92° / 33° | 174 #45 | 1992 | 53.5% | 34.7% | 88.9% |
| SuwanneePerry Foley (ASHRAE) | 2A | 91° / 30° | 134 #47 | 1991 | 45.0% | 47.7% | 90.8% |
| GilchristCross City (ASHRAE) | 2A | 92° / 30° | 94 #52 | 1997 | 47.7% | 49.8% | 92.4% |
| BradfordGainesville Regional Airport (Manual J) | 2A | 92° / 33° | 66 #56 | 1985 | 61.2% | 30.0% | 94.6% |
| DixieCross City (ASHRAE) | 2A | 92° / 30° | 66 #57 | 1988 | 44.4% | 50.5% | 91.6% |
| TaylorPerry Foley (ASHRAE) | 2A | 91° / 30° | 58 #58 | 1986 | 51.0% | 40.1% | 86.5% |
| UnionGainesville Regional Airport (Manual J) | 2A | 92° / 33° | 45 #60 | 1994 | 45.2% | 48.6% | 97.8% |
| LafayettePerry Foley (ASHRAE) | 2A | 91° / 30° | 41 #62 | 1990 | 57.0% | 37.5% | 90.3% |
| MadisonPerry Foley (ASHRAE) · Valdosta Regional, GA (ASHRAE) | 2A | 91° / 31° | 39 #63 | 1988 | 56.3% | 33.9% | 81.4% |
| HamiltonMoody Air Force Base, Valdosta GA (Manual J) · Valdosta Regional, GA (ASHRAE) | 2A | 94° / 31° | 34 #64 | 1990 | 49.6% | 42.4% | 84.9% |
What it means for sizing
2 paragraphs · design temperatures, housing stock, equipment
Three stations cover most of the region: Gainesville Regional for Alachua, Bradford, Columbia and Union (92°F, 33°F); Cross City for Gilchrist and Dixie (92°F, 30°F); and Perry-Foley for Lafayette, Suwannee and Taylor (91°F, 30°F).2 Hamilton and Madison draw partly on Valdosta, Georgia, with Hamilton's cooling limit reaching 94°F.2 All eleven are zone 2A.1
Bottled gas heats 8.5% of homes in Madison, 8.0% in Hamilton and 7.8% in Lafayette, far above the Florida peninsula.4 In our view that changes the Manual S conversation from heat-pump balance points to furnace or gas-pack sizing for a real share of jobs. Alachua is the region's centre of gravity, with 689 one-unit permits in 2025; most of the rest issued under 200.3
Worked example
1,900 sq ft house in Alachua County → 22,990 Btu/h, 1.92 tons · illustrative
Illustrative · not a Manual J
A 1,900 sq ft frame home at Gainesville's 92°F and 33°F limits. The heating line here is a large share of the cooling total, which is the point of including it.
| House | new single-storey frame home, Gainesville 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 0.3, 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 | 92°F cooling / 33°F heating (Alachua 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.
North Central questions
3 answers · What heating design temperature applies in Lake City or Live Oak?
What heating design temperature applies in Lake City or Live Oak?
Columbia County (Lake City) uses Gainesville Regional's 33°F heating limit, and Suwannee County (Live Oak) uses Perry-Foley's 30°F. Cooling limits are 92°F and 91°F. Those come from RESNET's county design-temperature table, so a Manual J shouldn't use colder winter or hotter summer conditions.
Do many North Central Florida homes heat with propane?
More than the rest of Florida. The 2020–2024 American Community Survey puts bottled-gas heating at 8.5% of occupied homes in Madison, 8.0% in Hamilton and 7.8% in Lafayette. If the house heats with propane, Manual S selects the furnace from its output rather than checking a heat pump's balance point.
Why do Hamilton and Madison counties use Georgia weather stations?
RESNET assigns the nearest qualifying station when a county has none suitable inside its borders. For Hamilton the cooling value comes from Moody Air Force Base near Valdosta and the heating value from Valdosta Regional; Madison's heating also comes from Valdosta. The resulting limits are 94°F/31°F and 91°F/31°F.
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