Lake County energy calcs & Manual J.
One energy set, four documents, and a thirty-day zoning window.
Lake County's single-family checklist asks for one energy-calc set from a Florida-registered design professional containing the R-405 form, Manual J, Manual S, and a full duct layout or a Manual D. Digitally sealed plans go in through the county's OPRS portal. Lake's design limits are 92°F cooling and 39°F heating, in climate zone 2A.
- Department
- Lake County Office of Building Servicesunincorporated · Lake County OPRS1
- Code edition
- FBC Energy Conservation, 8th Ed. (2023)9th Ed. (2026) scheduled for Dec 31, 2026 · what changes2
- Climate zone
- Zone 2A1% cooling 92°F · 99% heating 39°F3
- 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
- Evidence
- 10 primary sourcesEvery number on this page links to its source · references
What Lake reviewers ask for
The county's CL20 checklist, updated October 2025, is short and specific: one set of energy calculations from a Florida-registered design professional, and it must include the R-405 form, Manual J, Manual S, and a full duct layout or a Manual D.4 The 'or' means a duct layout drawn to the room loads can satisfy it without a separate D report; our full package includes both, so the choice stays yours.
The rest of the Lake submittal notes2 more paragraphs
Plans must be signed and sealed. Digitally sealed sets are submitted through Lake County OPRS; without a digital seal, the applicant brings plans with the original wet or raised seal and signature to the office and prints the approved set afterward.4 Product approval numbers are required too, if they aren't already on the plans.4
Timing has a trap. Approvals from the Office of Planning & Zoning are valid for only 30 days for submission to building, so a late truss package or energy calc can let them lapse.4 Parcels in the Green Swamp Area of Critical State Concern carry an extra checklist line of their own.4
Building departments
2 departments · addresses, phones, portals
Most of Lake's new houses are permitted by its cities. Unincorporated Lake issued 1,059 of the county's 3,999 one-unit permits in 2025; Clermont issued 561, Minneola 531, Groveland 355, Mount Dora 323 and Mascotte 317, each listed as its own permit-issuing place.78 Clermont's Building Services sits in City Hall.5 For the other cities, use each city's own building page.
| Department | Address | Phone | Portal |
|---|---|---|---|
| Lake County Office of Building Services (unincorporated) | 315 W. Main St., Tavares, FL 32778 | Official page | Lake County OPRS1 |
| City of Clermont, Building Services | 685 W. Montrose St., Clermont, FL 34711 | 352-394-4081 (City Hall) | City permitting5 |
Design conditions
92°F cooling · 39°F heating · zone 2A · weather stations
Cooling station: Leesburg Regional (ASHRAE). Heating station: Leesburg Regional (ASHRAE).3
Leesburg Regional supplies both of Lake's limits, 92°F cooling and 39°F heating, and Sumter uses the same station.3 Zone 2A.2 Lake's many lakes don't change the design table; in our view the 39°F heating limit is still cold enough that a heat pump's output at design belongs in the Manual S, not only its cooling rating.
Worked example
2,600 sq ft house → 31,530 Btu/h, 2.63 tons · illustrative
Illustrative · not a Manual J
A 2,600 sq ft, four-bedroom two-storey frame house. The frame walls, second storey and size are our assumptions for a south Lake new build, not census figures; the county median is 5.6 rooms.9 At 39°F, compare the heating line with the heat pump's output at design.
| House | new two-storey frame home, Clermont area |
|---|---|
| Conditioned area | 2,600 sq ft, 2 storeys, 9 ft ceilings |
| Bedrooms / occupants | 4 / 5 |
| Glazing | 15% of floor area (390 sq ft), U 0.32, 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 |
| Ventilation | mechanical, per FBC formula |
| Outdoor design | 92°F cooling / 39°F heating (sourced above) |
| Indoor design | 75°F cooling / 70°F heating |
| Design grains difference | 50 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. Code ceiling for single-stage cooling at 1.15× total load: 36,260 Btu/h.10
Local housing
Median year built 1997 · 67.5% single-family detached · Census ACS
Lake's housing is 67.5% single-family detached and 16.3% mobile homes.9 The median unit dates from 1997 and 44.7% were built from 2000 on; the median home has 5.6 rooms.9 Electric heat covers 87.3% of occupied homes, and owners occupy 77.6%.9
Utility rebates
Duke Energy Florida
- Duke Energy Florida. If Duke Energy Florida serves the address, its HVAC replacement program pays $300 toward an A/C or $500 toward a heat pump, capped at $1,000, provided a Home Energy Check was done in the past 24 months and a licensed contractor pulls the permit.6
Utility programs change often; check the program page before you count on a rebate.
Lake County questions
3 answers · What energy documents does Lake County require for a new home?
What energy documents does Lake County require for a new home?
One set from a Florida-registered design professional, containing the R-405 form, Manual J, Manual S, and either a full duct layout or a Manual D, per the county's single-family checklist. Product approval numbers go in too if they aren't on the plans. Digitally sealed sets are submitted online through OPRS.
Can I submit paper plans in Lake County?
Only if you can't get digitally signed and sealed plans. The county then takes plans bearing the original wet or raised seal and signature in its office, and the applicant prints the approved set after the permit issues. Digitally sealed plans are submitted online through the Lake County OPRS portal instead.
How long is a Lake County zoning approval good for?
Thirty days for submission to the building office, according to the county's single-family checklist. If the energy calc, truss package or sealed plans aren't ready, the Planning & Zoning approval can lapse before you file, so schedule the energy work so the whole package goes in together.
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.
Nearby and related
Sources
10 primary references · numbered to match the citations
- 01Lake County, Building Serviceslakecountyfl.gov
- 022023 Florida Building Code, Energy Conservation (8th Ed.), Table R301.1, climate zones by countyup.codes
- 03RESNET / ENERGY STAR, Appendix A: HVAC Design Temperature Limits by State and County (v4, 2019). 1% cooling and 99% heating values drawn from the ASHRAE 2013 Handbook of Fundamentals and ACCA Manual J 8th Ed.resnet.us
- 04Lake County Office of Building Services, CL20 Single Family Residential Permit Checklist (PDF, updated October 2025)cdn.lakecountyfl.gov
- 05City of Clermont, Building Servicesclermontfl.gov
- 06Duke Energy Florida, Rebate for HVAC Replacementduke-energy.com
- 07U.S. Census Bureau, Building Permits Survey, 2025 annual place data, South Region (1-unit housing units by permit-issuing place)www2.census.gov
- 08U.S. Census Bureau, Building Permits Survey, 2025 annual county data (new privately-owned 1-unit housing units)www2.census.gov
- 09U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates for Lake County, FL (B25018, B25024, B25034, B25035, B25003, B25040), via Census Reportercensusreporter.org
- 10Florida Building Commission, R405-2026 documentation checklist example (quotes R403.7.1.1 cooling equipment sizing limits)floridabuilding.org