Every property insurance policy covers some things and doesn't cover others. That part is obvious. What's less obvious is that insurance policies come in two fundamentally different designs for describing what they cover, and the design type changes how the policy behaves when something goes wrong.
The first design is called named perils. The second is called open perils, sometimes called "all-risk," though that term is a bit misleading because no policy covers everything. Understanding the difference between them is the foundation of understanding what your property insurance actually does.
The Whitelist and the Blacklist
The simplest way to understand the difference is to think of two different systems for deciding what's allowed.
A named perils policy works like a whitelist. It lists specific causes of loss, fire, lightning, windstorm, hail, explosion, theft, vandalism, smoke damage, and a handful of others. If your loss was caused by something on that list, you're covered. If it was caused by something not on the list, no matter how reasonable it might seem to expect coverage, you're not.
An open perils policy works like a blacklist. It says, in effect, "we cover every cause of loss except the ones we specifically exclude." The exclusions list is where coverage ends. Everything else, including things no one thought to list, things that are unusual, things that simply don't have a category yet, is covered.
That's a genuinely significant difference, and it matters most when something unusual happens.
What Gets Listed Under Named Perils
Named perils policies typically include a fairly predictable set of covered causes of loss. Most lists include:
- Fire and smoke
- Lightning
- Windstorm and hail
- Explosion
- Riot or civil commotion
- Aircraft damage
- Vehicles (damage caused by a vehicle hitting the property)
- Vandalism and malicious mischief
- Theft
- Falling objects
- Certain types of water damage (weight of ice or snow; sudden discharge from a plumbing system)
These cover a lot. The major, obvious disasters that most people think of when they think about property insurance, fire, storm, theft, are generally on the list. For most straightforward claims, the named perils approach does what's expected.
The gaps appear at the edges. What about a water pipe that freezes slowly rather than bursting suddenly? Whether that's covered depends on how the named perils list words its water damage coverage. What about mold that develops from a covered water event, is mold itself a named peril? Usually not, even if the water that caused it was covered. What about damage from an insect infestation, from an unusual chemical reaction, from a structural failure caused by soil movement? These are the kinds of losses that named perils policies frequently don't cover, not because the carrier made a specific decision about them, but because they weren't on the list.
How Open Perils Changes the Equation
Under an open perils policy, the same losses that would fall through a named perils gap are potentially covered, because coverage doesn't depend on whether someone thought to include a specific cause of loss in the list. If something damages your property and it isn't in the exclusions, it's covered.
This matters most for unusual or unexpected causes of loss. A pest control treatment that leaves residue damaging to surfaces. A structural failure connected to ground movement that isn't technically "earthquake" as defined in the policy. An electrical surge from a utility issue rather than lightning. Water backing up through a drain rather than a burst pipe. Under a named perils approach, each of these requires checking whether it's on the list. Under open perils, each of these requires checking whether it's on the exclusion list, and if it's not excluded, coverage follows.
The result is that open perils coverage provides a broader safety net for exactly the claims that are hardest to anticipate: the ones no one thought to specifically include in a list.
The Burden of Proof Difference
There's a less obvious but equally important difference between named perils and open perils that shows up when a claim is disputed: who has to prove what.
Under a named perils policy, the burden is on the policyholder to demonstrate that the damage was caused by one of the listed covered perils. If the cause is unclear or disputed, the policyholder needs to establish which named peril was responsible. If they can't, if the cause is ambiguous or doesn't match any listed peril exactly, the carrier can decline coverage without needing to prove anything themselves.
Under an open perils policy, the burden shifts. Coverage is the default. For a carrier to deny a claim, it must demonstrate that the loss was caused by one of the specifically listed exclusions. If the carrier can't establish that an exclusion applies, coverage follows.
This difference is most significant in complex or ambiguous claims, a fire with a disputed origin, water damage where the source is unclear, a loss where multiple causes may have contributed. In those situations, which party carries the burden of proof can determine the outcome of the dispute, independent of the underlying facts.
An Important Nuance: Same Policy, Different Approaches
Here's something that surprises many property owners: a single homeowner's policy often uses a different approach for the structure than it does for the contents.
Most comprehensive homeowner's policies (the HO-3 form, which is the most common type) use open perils coverage for the dwelling, the physical structure of the home. But the same policy often uses named perils coverage for personal property, the contents of the home.
This means that if something unusual damages the structure, it's likely covered. But if the same unusual thing damages the contents, furniture, clothing, electronics, it may not be, because the contents section requires matching a named peril.
This isn't a trick or a hidden provision. It's how the most common homeowner's policy form is structured. But it means that a claim involving both structural damage and contents damage can be handled differently for each component under the same policy, and that some contents losses that seem obviously connected to a covered event might not be covered if the specific contents damage doesn't match a named peril.
What This Looks Like for Rental Properties
Rental property policies, landlord policies, dwelling policies, and STR-specific commercial policies, vary significantly in their perils approach, and this is an area where lower-cost rental property policies often provide less protection than their premiums might suggest.
Basic dwelling forms (sometimes labeled DP-1) typically use named perils on everything, structure and contents alike. They cover the common disasters but leave the unusual causes of loss unaddressed. More comprehensive rental property policies use open perils on the structure, similar to a standard homeowner's policy. The most comprehensive STR-specific commercial policies use open perils on both structure and contents, providing the broadest coverage for the property's full profile.
Operators who chose a rental property policy primarily on price, without comparing the perils approach, may be carrying named perils coverage on a property that would benefit from the broader protection of open perils, particularly if the property has a complex amenity profile, unusual construction, or a history of claims from unexpected causes.
How to Know What You Have
The declarations page of your policy may describe the coverage form by name, HO-3, DP-1, DP-3, and similar designations correspond to specific policy forms with known perils approaches. If you know the form number, you can look up what it covers.
More directly, the policy itself will contain either a list of covered perils (named perils) or a list of exclusions with general coverage stated (open perils). The structure of that section tells you which approach applies.
If you're reading the policy and finding it difficult to tell, call your agent and ask: "Is my property covered on a named perils basis or an open perils basis? Does that apply to both the structure and the contents, or just one?" These are specific, answerable questions.
The Bottom Line
Named perils and open perils describe two fundamentally different ways of defining what an insurance policy covers, one by listing what's in, and one by listing what's out. The practical difference is most visible at the edges: the unusual damage, the unexpected cause, the loss that doesn't fit a standard category.
In a portfolio of ordinary claims from common causes, the difference may rarely appear. In a single unusual claim, the kind that doesn't fit neatly on a list, it can determine whether coverage applies at all.
Knowing which approach your policy uses, and whether it applies consistently to both structure and contents, is a foundational piece of understanding what your insurance actually does.
This article is prepared by Threshold STR for educational purposes and is intended as a general introduction to insurance concepts. Policy forms, covered perils, and exclusions vary by carrier, policy type, and state. It does not constitute insurance advice. For questions about your specific policy, consult with a licensed insurance professional.