Florida Wind Mitigation Insurance Credit Calculator

How this calculator works

Florida wind-mitigation insurance discounts are statutorily mandated under F.S. § 627.0629, which requires every Florida residential property insurer to offer premium reductions for hurricane-loss-mitigation construction features. The discount table is set by the Florida Office of Insurance Regulation (OIR) and binds every admitted carrier in the state — including Citizens Property Insurance (the state-backed insurer of last resort).

The discounts apply to the windstorm portion of the premium, not the total premium. For Florida coastal properties, the windstorm portion is typically 60%-80% of the total premium; for inland properties, 20%-40%. The wind-mit credit on a $3,000 windstorm-only premium that qualifies for a 45% discount saves $1,350 per year regardless of the total premium amount.

The construction features assessed are documented on the standardized Florida OIR Form OIR-B1-1802 by a licensed inspector. The form is the binding document insurers honor at policy bind or renewal — your insurer cannot demand a different inspection format if Form 1802 has been properly completed.

The calculator handles the five major discount categories:

1. Roof shape. Hip roofs (4-sided converging to a peak) qualify for ~18% discount. Gable, flat, and other shapes get 0%.
2. Roof deck attachment. Original toe-nailed 8d construction gets 0%. Plywood with 6d/8d nails escalates through 4%-12%. Rated sheathing with 12-inch nailing pattern reaches ~22%.
3. Roof-to-wall attachment. Toe-nail gets 0%. Clip/single-wrap/double-wrap escalates through 8%-22%.
4. Secondary water resistance. Required by Florida Building Code on new construction since 2010; common reroof addition for older homes. Yes/no for ~4% discount.
5. Opening protection. None (0%), basic non-rated shutters (~7%), hurricane-rated impact glazing or TAS-tested shutters (~22%).

The discounts compound multiplicatively, not additively. A 20% credit on roof deck attachment and a 20% credit on roof-to-wall attachment do not add to 40%; they combine to 1 − (0.80 × 0.80) = 36%. This is by design in the Florida OIR rate-filing methodology — each feature addresses partially-overlapping failure modes, so the residual-loss probability is multiplicative rather than additive.

A worked example

A 1995-construction Florida coastal home with a $3,000/year windstorm portion of premium. The wind-mit inspection comes back with the best possible rating across all five features:

• Hip roof: 18% discount
• Rated sheathing 12-inch: 22%
• Double wrap roof-to-wall: 22%
• Secondary water resistance: 4%
• Hurricane-rated openings: 22%

Multiplicatively combined: 1 − (0.82 × 0.78 × 0.78 × 0.96 × 0.78) = 62.6% — capped at the 60% observed-market ceiling in this calculator.

• Annual savings: $3,000 × 60% = $1,800/year
• 5-year cumulative: $9,000
• 10-year cumulative: $18,000

For the same home with all-baseline construction (gable roof, toe-nailed deck, toe-nail roof-to-wall, no SWR, no opening protection): 0% discount, $0 savings.

The combined-discount range across Florida coastal homes typically falls between 20%-50% — meaningful savings, but rarely the full 60%. The biggest dollar movers are the roof-to-wall attachment (toe-nail → wrap is often $400-$800/year in saved premium) and opening protection (none → hurricane-rated is often $500-$900/year).

The reroof / improvement opportunity

This is where the wind-mit credit becomes financially structural rather than incremental. A Florida coastal home considering a reroof in the next 5-10 years can plan the reroof to maximize wind-mit savings:

• Add rated sheathing if not already present: a typical $1,500-$3,000 reroof upgrade that captures $200-$400/year in additional discount.
• Add secondary water resistance: incremental $1,500-$3,000 during reroof, ~4% additional discount worth $100-$200/year.
• Re-do roof-to-wall attachment during reroof if access is available: highest-leverage single move, $5,000-$15,000 cost, often $400-$800/year in savings.

A $15,000-$20,000 incremental investment during a reroof captures $700-$1,400/year in additional wind-mit credit, paying back in 15-25 years through insurance savings alone — and that's before counting the storm-protection benefit of the better construction or the substantially lower deductible exposure during a covered hurricane event.

Florida's post-2022 insurance market has made this calculus more compelling. With base premiums up 30%-80% across coastal Florida, every percentage point of wind-mit credit is worth more dollars. The 60%-of-windstorm cap has not moved, but the dollar value of hitting it is larger than ever.

What the calculator does not do

This calculator is a planning estimator. It does not:

• Substitute for an actual Form 1802 inspection. The calculator computes the discount based on what you enter; the insurer pays the discount based on what the inspector documents on the actual Form 1802. Inspector findings sometimes differ from owner expectations — particularly on roof-to-wall attachment, which often requires attic access for visual verification.
• Capture carrier-specific filings. The discount rates in this calculator are at the regulatory floor; specific Florida insurer filings can produce higher discounts on the best-rated homes (some carriers go as high as 65%-70% all-in for ideal construction). The actual policy quote from your carrier should match or exceed the number here.
• Compute the total-premium impact. The discount applies to the windstorm portion; the all-other-perils (AOP) and liability portions are unaffected. If you don't know the windstorm portion specifically, ask your agent to break out the windstorm-specific premium on the declarations page.
• Handle commercial-residential master policies on condos. This calculator is for single-family residential and individual condo unit (HO-3, HO-6) policies. The commercial-residential master policy on a condo association has its own wind-mit framework with different forms and a more complex inspection model. Use the Master Policy Deductible Allocation Calculator for the deductible side of that exposure.
• Account for sinkhole or flood coverage discounts. Wind-mit is specifically about hurricane-loss mitigation; sinkhole and flood are separate insurance products with their own rating methodologies.

How this page is maintained

F.S. § 627.0629 has been stable since the 2002 amendments that established the modern wind-mit credit framework. The Form 1802 has been refined periodically — most recently in 2024 to clarify reroof-documentation requirements — but the substantive feature categories have not changed. The dollar values of typical discounts move with carrier rate filings; we refresh the rate table at least annually against Florida OIR rate filings. If the legislature or OIR substantively changes the discount structure, this page is updated and re-stamped within the quarter.

Last reviewed: 2026-05-14 against F.S. § 627.0629, § 627.711; Florida OIR Form OIR-B1-1802; OIR rate filings 2024-2026.