The 80% Rule, a Fire, and a Garage the Limit Won't Reach
A Minnesota homeowner insures a 1962 house on an HO-3 with Coverage A of $280,000, a $1,000 deductible, and no inflation guard. The cost to rebuild the dwelling at the time of loss is $400,000. A kitchen fire causes $120,000 in repair cost and $80,000 in actual cash value. The same fire destroys a detached garage; replacing it costs $45,000. Coverage B is the standard 10% of Coverage A. The insured has owned the home for nine years, and her agent simply renews each year at the same Coverage A amount without a conversation about rebuilding cost. She wants to know whether she can collect the full $120,000 and the full $45,000.
1. Compute what the insured can collect for the dwelling fire damage. Show each step.
Read the worked answer
Step 1 - Insurance-to-value requirement. 80% × $400,000 (replacement cost at time of loss) = $320,000 required to earn full replacement cost settlement.
Step 2 - Compare to the limit. Coverage A is $280,000, which is only 87.5% of the $320,000 requirement, so the policy is underinsured and the loss-settlement formula applies.
Step 3 - Apply the formula. When the limit is below the 80% requirement, the HO-3 pays the greater of:
- actual cash value of the damage = $80,000, or
- (limit ÷ 80% requirement) × loss = ($280,000 ÷ $320,000) × $120,000 = 0.875 × $120,000 = $105,000.
The greater figure is $105,000.
Step 4 - Deductible. $105,000 − $1,000 = $104,000 payable.
Lesson. Paying $105,000 on a $120,000 repair is the coinsurance penalty: roughly $16,000 of the loss is self-insured. Had the limit been at least $320,000, the full $120,000 replacement cost would have been paid (up to the limit). Note also that a total loss here would pay only $280,000 against a $400,000 rebuild.
2. Compute the recovery for the destroyed detached garage, and explain whether Coverage B adds to or draws down Coverage A.
Read the worked answer
Limit. Coverage B (other structures) on the HO-3 is 10% of Coverage A = 10% × $280,000 = $28,000.
Loss. Replacement cost of the garage is $45,000. Coverage B is a sublimit, so the maximum available is $28,000; the remaining $17,000 is uninsured.
Adds to, does not draw down. Coverage B is in addition to the Coverage A limit - a garage loss does not erode the dwelling limit, and the two are separately capped. Credit against the Coverage A limit would only arise under forms that treat other structures as part of the dwelling limit, which the HO-3 does not.
Deductible. One deductible applies per occurrence. Because the $1,000 was already absorbed against the dwelling loss, the garage payment is the full $28,000 rather than $27,000.
Total for the occurrence. $104,000 (dwelling) + $28,000 (garage) = $132,000.
3. The insured asks why the limit was never raised. What should the agency do now, and how should the coverage be restructured at renewal?
Read the worked answer
Acknowledge the gap, do not litigate it at the kitchen table. The agency should document that the limit was carried forward by renewal habit without an inflation-guard endorsement or a replacement-cost conversation. That is an E&O exposure worth reporting to the agency's carrier, and it should be handled factually and in writing - no admission of legal liability, no promise of payment.
Restructure at renewal.
- Raise Coverage A to at least $320,000 to cure the coinsurance penalty, and ideally to the full $400,000 rebuild cost so a total loss is funded.
- Add an inflation guard so the limit tracks construction costs between renewals; a nine-year static limit on a 1962 home is a systemic problem, not a one-off.
- Review Coverage B, since 10% of an underinsured Coverage A produces a garage limit ($28,000) far below the $45,000 replacement cost. Consider an increased other-structures limit by endorsement.
- Confirm the loss-settlement basis and extended replacement cost options, and re-run the whole book for the same renewal habit.
Timing. Do not increase limits retroactively or backdate an endorsement to capture this loss - that is a misrepresentation to the insurer and a licensing problem.