Signals: S4 Valuation & Appraisal Gap · S1 Insurance Repricing · S6 Chronic Climate Stress
Miami-Dade now records 133 days above 90°F a year. In 1970, it recorded 84. That is 49 more days a year of cooling load than the building stock was designed for.
One number in a pro forma captures that shift, and most underwriting templates still use a 4% escalator. Before 2019, a 4% escalation rate was standard and generally safe. The market was relatively stable, and minor rate adjustments could be easily absorbed within a typical underwriting pro forma.
This brief walks a single Miami-Dade asset line by line, corrects that one input to the market, and shows where the value goes.
Market Signal
Start with what the market actually did rather than what a model assumed.
Across the four major commercial asset classes, insurance costs grew 154% between 2017 and 2024, a compound annual rate of 14.3%. Multifamily was the steepest. Per-unit insurance went from $285.83 in 2017 to $878.91 in 2024, up 207.5%.
By 2024, insurance consumed 6.6% of multifamily net operating income. Across all property types, it was 4.1%, up from 1.9% in 2017. Multifamily in high-risk markets pays 69% higher premiums than comparable assets in low-risk markets, and trades at roughly a 25% discount to those low-risk comps.
The physical driver in South Florida is chronic rather than acute, which is why it is easy to underweight. Miami-Dade’s days above 90°F rose from 84 to 133 a year since 1970, on the county government’s own count. Heat drives cooling load, cooling load drives equipment wear, and equipment wear drives both operating cost and capital timing.
Sitting underneath that is the acute exposure. Much of the county’s developable land carries a FEMA Zone AE designation, the 1% annual chance floodplain, which triggers mandatory purchase of flood insurance for federally backed loans.
The code has moved with the hazard. Florida’s 8th Edition Building Code, effective December 31, 2023, adopted ASCE 7-22 wind load provisions. Since 2023, new construction is being built to a higher standard than existing stock, which means every older asset competes against buildings that can be insured and financed more cheaply.
A second insurance line is often treated as a footnote in most Florida pro formas. Flood is severable from property coverage in the United States, priced federally, and moving toward full risk under FEMA’s Risk Rating 2.0.
The direction is documented. In December 2022, the median annual NFIP premium was $689. Full-risk pricing requires that median to rise to $1,288. That is an 87% increase to the actuarial number, delivered under a statutory cap of 18% per year.
The cap is what investors misread. It does not lower the destination. It stretches the timeline, which makes the increase scheduled rather than uncertain. The good news is that a capped, published trajectory toward a known endpoint is the easiest kind of cost to forecast. The bad news is that most pro formas still carry it flat.
Roughly 9% of policyholders will eventually need increases above 300%, and Florida sits with the other four Gulf Coast states in GAO’s highest premium-increase group, where 61% of NFIP policies are concentrated.
Deal Scenario
What follows is a modeled composite using a single-line insurance correction applied to an unchanged pro forma, capitalized at the going-in rate, with the escalator calibrated to the observed 14.3% compound rate across CRE asset classes.
A 200-unit multifamily asset in Homestead, in southern Miami-Dade County, acquired in mid-2021 for $38 million at a going-in cap rate of 6.5%.
Nothing about that transaction was unusual at the time. The original underwriting carried insurance at $840,000 per year, about $4,200 per unit. Debt service coverage sat comfortably above the lender’s 1.20x covenant. The projected levered IRR over a seven-year hold was 8.2%.
Solid underwriting. Acceptable returns. A deal that any committee approves.
The 2026 renewal quote is $1.68 million. That is a 100% increase on a building that has not changed!
Work it through. The annual NOI impact of that line alone is a negative $840,000. That money leaves the property and doesn't come back through rent, because the submarket is competing on concessions.
DSCR now sits at approximately 1.20x, directly on the covenant rather than above it. That is not a cushion. That is a trigger waiting for one more bad quarter.
Next, capitalize it. At the going-in 6.5% cap rate, an $840,000 NOI reduction implies a value decline of about $12.9 million against a $38 million purchase price.
Layer in the other lines that moved with it, principally cooling-driven operating cost and pulled-forward capital replacement, and now unmodeled NOI deterioration approaches $936,000 per year. At the same cap rate, that is roughly $14.4 million of value erosion, about 38% of the original purchase price.
The 8.2% target IRR is not achievable from here. Not because the market turned, and not because the asset underperformed operationally. One line item was modeled at 4% in a market compounding at 14.3%.
The heat data matters here in an easy-to-miss way because it does not appear as a line labeled ‘heat’.
Forty-nine additional days above 90°F per year represent a 58% increase in days when cooling equipment runs at or near capacity. That shows up first in electricity costs, then in maintenance frequency, then in a replacement cycle arriving earlier than the assumed reserve schedule.
A chiller specified for a 1990s Miami summer and replaced on a twenty-year schedule is being asked to do materially more work than its reserve assumed it could. The reserve was not wrong when it was set. The duty cycle changed underneath it.
That is the chronic-risk pattern. No event, no claim, no damage. Just a building doing more work than it was designed for, paid for with a capital budget sized for the old climate.
Underwriting Analysis
The instinct is to treat this as a Florida problem. It is not. It is a modeling convention problem that Florida happened to expose first.
Three corrections make a pro forma climate-adjusted, and none of them require a new model.
Escalate insurance to the observed market rate, not to inflation. The 14.3% compound rate across CRE asset classes is the empirical anchor. Modeling 4% is not conservative. It describes a market that no longer exists. If you want a conservative case, model the observed rate and test what happens above it.
Solve for the covenant, not the return. Identify the DSCR floor in the loan documents and find the insurance level that breaches it. That number is your real constraint, and it usually arrives years before the IRR disappoints.
Capitalize the operating change, not just the cash flow. An NOI reduction is not only a distribution problem. At any cap rate, it is a valuation event, and the multiple works against you in exactly the years you least want it to.
Then add the diligence step that would have caught this at acquisition. Get the current declarations page and three cycles of renewal correspondence before you model anything. The trajectory is in those documents. It is not in the trailing twelve months.
The insurance escalator compounds through every year of the hold and then feeds the terminal value through NOI, so it damages the return twice. The exit cap, which usually drives the sensitivity table, only affects the terminal value.
Strategic Implications
The broader consequence is that a pro forma is a statement about the future written in the language of the past, and one of its inputs has stopped behaving as expected.
Every other line in that Homestead model was defensible. Rent growth, expense ratios, capital reserves, exit timing. The insurance escalator was defensible too, in 2019, which is roughly when the template it came from was written.
That is the failure mode worth internalizing. Assumptions do not become wrong loudly. They become wrong quietly, while still looking like the same reasonable number they always were, and nobody re-derives them because nobody remembers deriving them.
For a portfolio, the practical move is to re-underwrite the insurance line across every asset at once rather than at each renewal. Renewals arrive one at a time, which makes each increase look like an isolated event. Run them together, and the pattern is obvious.
For acquisitions, the discipline is to treat any multifamily market where insurance exceeds roughly 6% of NOI, or any other property type above roughly 4%, as one in which the insurance line is now a primary underwriting variable rather than an operating expense. The national multifamily figure reached 6.6% in 2024, against 4.1% across all property types. Miami-Dade multifamily is well past both.
A portfolio version of this matters more than the single deal. If one asset’s insurance line was modeled at 4%, every asset in the fund was, because they came from the same template.
That means the exposure is correlated in a way a diversification analysis will not show. Geographic diversification protects against a hazard affecting two assets at the same time. It does not protect against the same modeling assumption being wrong in every market simultaneously, and an escalator assumption is wrong everywhere or nowhere.
For a fund approaching the end of an investment period, the practical exercise is to rerun all assets at the observed rate in a single pass and focus on the aggregate DSCR position rather than individual returns. The assets that breach will do so in a cluster because they share the error.
Brief 5 ran these numbers on a Sun Belt portfolio and found the covenant to be in breach in year three. Brief 15 applies the same logic to the Netherlands, where a legal deadline, rather than the insurance market, forced the repricing.
As always, KNOW YOUR SIGNALS and BE CLIMATE READY!
Jamie
Run this on your own deal
The CRDF Deal Stress Test™ built for this brief takes your pro forma, escalates insurance at the observed market rate, and solves for the year your DSCR covenant breaks. Free, no signup: Brief 14 CRDF Deal Stress Test™ (xlsx)
New to the framework? The blank master Signal Tracker and Deal Stress Test workbooks are at climatereadyre.com/tools.
Related briefs
Same signal (S4 Valuation & Appraisal Gap):
Brief 5 · Sun Belt Multifamily Insurance and IRR: Climate Risk Behind a 207% Rise
Brief 2 · Houston Multifamily Insurance: $1,115 per Unit, Up 40.4%
Brief 4 · How Much Does Coastal Hotel Insurance Cost? Florida Trends & Benchmarks
Next in sequence:
Brief 15 · The Netherlands Label C Rule: How a Deadline Moved a Market to 78% Compliance - coming soon
Sources
Every figure above, with the date the data covers, the date it was published, and the date I verified it.
Miami-Dade extreme heat days — days above 90°F rose from 84 to 133 per year since 1970, per Miami-Dade County, which states the figure without a source of its own
Miami-Dade County — Extreme Heat · Data as of 1970–2024 · Published date not stated · Accessed Sep 2026
Pre-2019 insurance escalation assumption — a 4% annual escalator was standard underwriting practice before the Florida insurance market repriced; it no longer tracks the market.
E&E News — Fla. insurance crisis deepens as rates soar, companies fall · Data as of 2022 · Published Sep 19, 2022 · Accessed Sep 2026
Florida Housing Finance Corporation — Board package, consent agenda (September 19, 2025) · Data as of 2025 · Published Sep 2025 · Accessed Sep 2026
Trepp — TreppTalk: Florida multifamily insurance costs · Data period not stated · Published date not stated · Accessed Sep 2026
Origin Investments — Florida Insurance Risk: Why Institutional Multifamily Is Different · Data period not stated · Published date not stated · Accessed Sep 2026
The 4% escalator is the pre-2019 underwriting convention as it appeared in deal templates, stated here as a convention rather than a published figure. None of the four items states it as a number. E&E News documents the Florida repricing that made it obsolete, and the Florida Housing, Trepp, and Origin items are context on the same market.
Insurance cost growth across CRE asset classes — +154% (2017–2024), 14.3% CAGR; insurance 6.6% of multifamily NOI and 4.1% of all-property NOI in 2024, up from 1.9% in 2017
First Street Foundation research, reported via Bisnow · Data as of 2017–2024 · Published May 5, 2026 · Accessed Aug 2026
Multifamily insurance per unit — $285.83 (2017) to $878.91 (2024), +207.5%
First Street Foundation research, reported via Bisnow · Data as of 2017–2024 · Published May 5, 2026 · Accessed Aug 2026
High-risk multifamily premium and pricing gap — 69% higher premiums; roughly 25% discount to low-risk comps
First Street Foundation research, reported via Bisnow · Data as of 25 years of NCREIF performance data across 120 US metros · Published May 5, 2026 · Accessed Sep 2026
FEMA Zone AE — the 1% annual chance floodplain, triggering mandatory purchase for federally backed loans
FEMA Flood Maps · Data as of 2024 · Published 2024 · Accessed Aug 2026
Florida Building Code — 8th Edition (2023) incorporates ASCE 7-22 load provisions
Florida Building Code, via ICC · Data as of Dec 31, 2023 · Published 2023 · Accessed Sep 2026
Effective December 31, 2023, with ASCE 7-22 governing wind loads.
NFIP Risk Rating 2.0 pricing path — median premium $689 (December 2022) rising to $1,288 at full risk; 18% statutory annual cap; roughly 9% of policyholders eventually need increases above 300%; all five Gulf Coast states, Florida included, are in the highest premium-increase group, which holds 61% of NFIP policies
US GAO — GAO-23-105977 · Data as of Dec 2022 · Published Jul 31, 2023 · Accessed Aug 2026
200-unit Homestead asset — $38M at a 6.5% going-in cap (mid-2021), insurance $840,000 rising to $1.68M, DSCR at the 1.20x covenant, NOI deterioration approaching $936,000, value erosion approximately $14.4M, original target IRR 8.2%
CRREI modeled composite · Method: single-line insurance correction applied to an unchanged pro forma, capitalized at the going-in rate, escalator calibrated to the observed 14.3% compound rate · Modeled — not a specific transaction
Commentary and analysis only. Not investment, financial, legal, tax, or professional advice. CRDF tools are illustrative; examples are composites drawn from public data. Do your own due diligence and consult qualified professionals.
I run this analysis on specific deals. If you are underwriting a South Florida or Gulf Coast asset and want the insurance escalator and covenant headroom pressure-tested before you sign, book 20 minutes.
Jamie Wolf, MBA — Founder & Publisher, Climate-Ready Real Estate Investing, © 2026, CR REI Holdings LLC