Form R405 vs R402: which Florida energy path fits the house.
Form R402 is Florida's prescriptive path: every envelope component meets a table value. Form R405 is the performance path: software shows the home's annual loads, normalized for equipment efficiency, are at most 95% of the code's standard reference design (85% from December 31, 2026), so a weak component can be traded for a strong one. Both keep the mandatory provisions.
- Code basis
- FBC Energy Conservation, 8th Ed. (2023)9th Ed. (2026) scheduled for Dec 31, 2026 · what changes1
- In this guide
- 4 sections + side by sideThree ways to comply · R402: meet the table · R405: model the house · How we choose
- Reviewed by
- Designda Inc.Florida engineering firm license PE 39202 · verify
- 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
- 7 primary sourcesCode sections and county checklists, numbered · references
Three ways to comply
Florida's residential energy code allows three compliance routes: Sections R401 through R404 (prescriptive), Section R405 plus the provisions labeled 'mandatory' (performance), or the energy rating index approach of Section R406.1 For houses of three stories or fewer, the prescriptive route is documented on Form R402 or a Florida REScheck printout, and the performance route on Form R405 generated by Commission-approved software.2
R402: meet the table
The prescriptive path sets component values by climate zone. In zone 1 the table asks for…
The prescriptive path sets component values by climate zone. In zone 1 the table asks for R-30 ceilings, R-13 wood-frame walls, R-3/4 mass walls and SHGC 0.25 glazing with no fenestration U-factor requirement; zone 2 raises the ceiling to R-38 and mass walls to R-4/6 and caps fenestration at U-0.40.1 Which column applies depends on your county's zone in Table R301.1.3
R402 is simple to check, which reviewers like, but it is unforgiving: one window schedule over the SHGC limit and the form fails, even if the house is otherwise excellent.
R405: model the house
The performance path compares the proposed house with a standard reference design built to…
The performance path compares the proposed house with a standard reference design built to the code's baseline. On Florida's performance path (Form R405), the proposed home's annual heating, cooling and water-heating loads, normalized for equipment efficiency, must come in at no more than 95% of the code's standard reference design under the 8th Edition (2023) Florida Energy Code, tightening to 85% under the 9th Edition (2026) effective December 31, 2026, and every mandatory code requirement must still be met.14 EnergyGauge reports this comparison as the e-Ratio (0.95 or less to pass today). It is a comparison of normalized loads, not of energy bills.5 The software must be approved by the Florida Building Commission, the compliance report goes in with the permit, and an as-built report is due before the certificate of occupancy.1
Even on R405, a floor of mandatory items applies: supply and return ducts outside the thermal envelope need at least R-6 insulation (R-8 for site-wrapped supply ducts), ceilings need at least R-19 where space permits, and the air-leakage test still has to be done.1 For the 9th Edition, scheduled for December 31, 2026, the performance path's target tightens to an e-Ratio of 0.85, the ceiling on the proposed design's area-weighted window SHGC drops from 0.50 to 0.40, and the R405 duct-testing exception is removed.46
How we choose
We default to R405 for new homes because it lets a builder keep a large slider or a dark…
We default to R405 for new homes because it lets a builder keep a large slider or a dark roof and pay for it elsewhere, and because counties increasingly expect it; Lee County asks for R405 as the cover sheet on new homes.7 We use R402 for small additions and simple houses where every component already beats the table, because it is quicker for the reviewer to verify.
Side by side
6 rows · Form R402 (prescriptive) vs Form R405 (performance)
| Form R402 (prescriptive) | Form R405 (performance) | |
|---|---|---|
| Code section | R401–R404 | R405 + mandatory provisions |
| How it passes | Each component meets Table R402.1.2 | Normalized annual heating, cooling and water-heating loads ≤ 95% of the standard reference design (85% from Dec 31, 2026) |
| Software | Form or Florida REScheck printout | Commission-approved software printout |
| Trade-offs allowed | No | Yes, across envelope and equipment |
| As-built report | Not required by R405.4.2 | Required before the certificate of occupancy |
| Best fit | Additions, simple houses | New homes, glass-heavy or unusual designs |
Questions
3 answers · Can I switch from R402 to R405 after plan review comments?
Can I switch from R402 to R405 after plan review comments?
Yes, if the building department accepts a revised compliance form, and most simply review the new one. Switching is often the fastest fix when a single window or door fails the prescriptive SHGC. We revise plan-review comments on the same design free, including a change of compliance path.
Is REScheck accepted in Florida?
For the prescriptive path, yes: the energy code allows a Florida REScheck computer printout instead of Form R402 to show compliance with Sections R402, R403 and R404 for residential buildings of three stories or fewer. The performance path requires Form R405 generated by Commission-approved software instead.
What does the 95 percent in R405 mean?
Under the 8th Edition (2023) Florida Energy Code, the home's annual heating, cooling and water-heating loads, normalized for equipment efficiency, must be at most 95 percent of the standard reference design (e-Ratio 0.95 or less), with every mandatory requirement met. It compares normalized loads, not energy bills. From December 31, 2026 (9th Edition) the limit is 85 percent.
County requirements and related guides
Sources
7 primary references · numbered to match the citations
- 012023 Florida Building Code, Energy Conservation (8th Ed.), Chapter 4 [RE]: R401–R406up.codes
- 022023 Florida Building Code, Energy Conservation (8th Ed.), Chapter 1 [RE]: R101.5, R103 compliance forms and certificationup.codes
- 032023 Florida Building Code, Energy Conservation (8th Ed.), Table R301.1, climate zones by countyup.codes
- 04Florida Building Commission, Analysis of Changes for the 9th Edition (2026) Florida Codes, Energy (Residential): R405.3floridabuilding.org
- 05FSEC-CR-2128-25 for DBPR, 2024 IECC vs 2023 FBC-EC residential code review (Florida Building Commission, Energy TAC)floridabuilding.org
- 06DBPR, Significant Provision Changes, 9th Edition (2026) FBC-Energy Conservationfloridabuilding.org
- 07Lee County, Digital Projects FAQ (Form R405 cover sheet)leegov.com