Treasure Coast: energy calcs & Manual J.
Two quieter coastal counties between Brevard and Palm Beach.
Indian River and Martin counties are both climate zone 2A, with 90–91°F cooling and 41–43°F heating design limits. Neither issued more than 900 new single-family permits in 2025. Their neighbours St. Lucie and Brevard now have full pages, built from their own checklists; these two stay here until we've read theirs.
- Counties
- 2 countiesIndian River and Martin
- 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
Indian River and Martin
Per-county table2 counties · zone, design °F, permits, housing
| County · stations | Zone | Design °F | Permits | Median built | Single-family | Mobile | Electric heat |
|---|---|---|---|---|---|---|---|
| MartinSt Lucie County Intl. (ASHRAE) | 2A | 90° / 41° | 843 #33 | 1986 | 54.2% | 8.8% | 92.9% |
| Indian RiverVero Beach Municipal Airport (Manual J) · Vero Beach Municipal (ASHRAE) | 2A | 91° / 43° | 178 #44 | 1991 | 65.9% | 7.3% | 93.5% |
What it means for sizing
2 paragraphs · design temperatures, housing stock, equipment
Martin takes the St. Lucie County International station, 90°F cooling and 41°F heating, while Indian River's limits come from Vero Beach: 91°F and 43°F.2 Both are zone 2A.1 Our reading: a two-degree heating difference across one county line rarely changes equipment, but it does change the heating line on the Manual J, so use the county the house is actually in.
Martin issued 843 one-unit permits in 2025 and Indian River 178.3 Martin's housing is the older of the two, with a 1986 median and 33.5% built before 1980; Indian River's median is 1991.4 Owner occupancy is about 80% in both.4 St. Lucie and Brevard, which issued over 3,300 permits each, moved to their own pages on October 10, 2026.
Worked example
1,900 sq ft house in Martin County → 24,960 Btu/h, 2.08 tons · illustrative
Illustrative · not a Manual J
A 1,900 sq ft block home in Martin, where the median home has 5.3 rooms.4 The 45-grain moisture difference is our coastal assumption; the limits are Martin's 90°F and 41°F.
| House | new single-storey block home, Stuart area |
|---|---|
| Conditioned area | 1,900 sq ft, 1 storey, 9.33 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 | 90°F cooling / 41°F heating (Martin 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.
Treasure Coast questions
3 answers · What design temperatures apply in Stuart and Martin County?
What design temperatures apply in Stuart and Martin County?
Martin County uses the St. Lucie County International station: 90°F at 1% cooling and 41°F at 99% heating, per RESNET's county table. Those are the maximum design conditions a Manual J for a Martin County house should use; St. Lucie and Okeechobee counties share the same pair.
Why don't Indian River and Martin have their own pages?
We publish a county page only after reading that county's own permit checklists and confirming its building departments, and we haven't finished either county yet. Until then this hub carries their verified design temperatures, climate zone, permit volume and housing data. Ordering and pricing work the same statewide.
Is Indian River County in climate zone 1 or 2?
Zone 2A, like Martin, St. Lucie and Brevard. The 8th Edition energy code's Table R301.1 reserves 1A for seven South Florida counties, and none of the Treasure Coast is among them. Indian River's design limits are 91°F cooling and 43°F heating, from Vero Beach.
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