What happens if your house is underinsured?
Home insurance is designed to protect what is often a household’s biggest financial asset. Yet many owners may not be able to say with confidence whether their cover would be enough if the worst happened. Underinsurance—having a policy that does not fully cover the cost of rebuilding, repairing or replacing your home—can create serious financial stress after a claim.
Fei Huang, an associate professor in the School of Risk and Actuarial Studies at the University of NSW Business School in Sydney/Gadigal, says many home owners don’t realise they are underinsured. She warns that because a home is frequently a person’s largest asset, being underinsured can cause real financial distress if something goes wrong.
Survey data suggests the issue is widespread. In an Australia Institute poll last year, 15 per cent of home owners surveyed said their home was underinsured. But even that figure may not capture the full picture, because, as insurance expert Daniel Graham from consumer group Choice notes, many people would struggle to accurately assess whether they are underinsured.
What “underinsured” actually means
In practical terms, being underinsured means your insurance policy won’t fully cover the cost of rebuilding, repairing or replacing your home, according to the government’s MoneySmart website. Home insurance generally covers damage or loss caused by events such as natural disasters, theft and accidents. The problem arises when the maximum amount your insurer will pay—your “sum insured”—is set too low.
The sum insured on a home or home and contents policy should not be less than the potential costs you may face if you need to repair or rebuild. The Insurance Council of Australia describes underinsurance as occurring when a home insurance policy’s sum insured falls short of what it would actually cost to repair and rebuild a property.
This gap can be easy to miss during day-to-day life. Premiums are paid, the policy is renewed, and the sum insured may not be revisited. But if a major event causes extensive damage—or a total loss—the shortfall becomes immediately real.
How policy clauses can reduce payouts when you’re underinsured
Underinsurance can affect more than just the final dollar figure on your policy schedule. MoneySmart warns that a “coinsurance” or “averaging” clause can influence how much an insurer will pay out if you are underinsured.
These clauses can limit the insurer’s liability on claims to the proportion of the replacement value that has been insured. In other words, the insurer may apply a proportional approach to the payout if the property is not insured for its full replacement cost.
MoneySmart provides an example: if you’re insured for 67 per cent of your home’s value—meaning you are underinsured by 33 per cent—then under a coinsurance clause the insurer might only pay 67 per cent of the amount you are insured for if the home was destroyed. The details depend on the policy, but the key point is that underinsurance can reduce a claim payment in ways some households do not anticipate.
Why underinsurance can “creep up” over time
MoneySmart says home and contents underinsurance is “very common” in Australia and “can creep up on you”. One reason is that the cost to rebuild a home can change, sometimes quickly, while the sum insured may remain based on an earlier estimate.
The Insurance Council of Australia says the underinsurance problem is being worsened by trends outside the insurance industry. It points to construction costs rising more than 40 per cent since 2020, meaning some home owners’ cover may no longer reflect current rebuild costs.
That matters because rebuilding costs are not necessarily the same as a property’s market value. Rebuild costs can be affected by construction price changes and the specific work required to restore a property after a loss.
Dr Huang also links underinsurance pressures to rising premiums and inflation, which may have left more households underinsured. When budgets are tight, it can be tempting to keep sums insured lower or avoid adjusting cover upward at renewal time. The trade-off, however, is the risk of a large gap between what you need and what your insurer will pay.
Replacement cost vs “outdated value”
According to Mr Graham, underinsurance is mostly caused by home and contents not being insured at replacement cost. Replacement cost is the amount it would cost to replace everything new at today’s price. If your policy reflects an “outdated value”, you may be paying for cover that looks adequate on paper but does not match real-world costs when you need to claim.
Underinsurance can also occur in other ways. Some policy holders may have home insurance but no contents insurance. Others may be uninsured for specific scenarios such as flood or fire. These gaps can become critical depending on the event that causes damage or loss.
What can happen after a major loss
The financial consequences of underinsurance are most severe in a total-loss scenario, when a home is destroyed and needs to be rebuilt. Mr Graham says the big risk is experiencing a total loss and needing to rebuild, only to find the amount insured isn’t enough to replace everything new.
In that situation, he says, the insurer might tell you the amount you insured the building for is not enough and offer a cash settlement. That can leave the policy holder organising construction and substantially out of pocket.
Dr Huang says if an underinsured home is destroyed, owners will likely have to rebuild to a lower standard. Mr Graham also outlines difficult options that may follow: you might need to reduce the size or standard of your home, or sell the land and buy in a more affordable area.
These outcomes underline why the sum insured is not just an administrative detail. It can shape what recovery looks like after a disaster, and whether a household can restore its living situation without major financial compromise.
Is underinsuring worth it to save on premiums?
With home insurance premiums continuing to rise—and properties in natural disaster-prone areas paying the most—some households may wonder whether there is an advantage to being underinsured if it results in a lower premium.
Both Mr Graham and Dr Huang do not think it is worth the risk. Dr Huang says that unless you are very wealthy, you probably cannot absorb the losses home insurance is designed to protect against. Mr Graham’s view is blunt: underinsuring “really goes against the point of the product”. He adds there are better ways to get a lower home insurance premium.
How to reduce the risk of being underinsured
Experts recommend making insurance reviews a routine part of home ownership. The Insurance Council of Australia recommends reviewing the amount your home is insured for annually and always after renovations.
It suggests using your insurer’s online rebuild calculator, ensuring your policy accounts for demolition, professional fees, and current building code compliance, and speaking to your insurer or broker if you have any doubt.
Mr Graham and Dr Huang also recommend using the online calculator tools insurers provide. While these tools can be a useful starting point, Mr Graham says it is also important to think about your own possessions and property and how much it might cost to replace them.
Calculating contents cover: a practical approach
Contents insurance can be another area where underinsurance is common, especially if people underestimate the value of everyday items. Mr Graham says a basic method for calculating contents insurance is to go from room to room and list items.
This includes substantial items such as furniture and appliances, but also smaller things that add up—such as clothing. The aim is to arrive at a realistic replacement cost, rather than a rough guess or an amount based on what items once cost.
Mr Graham suggests reassessing home and contents insurance at least every few years, but ideally when the renewal notice arrives. It is also important to consider renovations and additions, such as installing air conditioning, which can change rebuild and replacement costs.
Shopping around for better value
For households trying to manage premium increases, shopping around is one of the strategies recommended by experts. When your renewal notice arrives, Mr Graham recommends spending an hour or two on a weekend getting quotes from different providers.
He suggests aiming for at least four or five quotes, and says using an independent comparison website can help. He also notes there is a huge range in insurance prices and that taking the time to shop around can, in most cases, result in a better deal.
Dr Huang agrees that comparing quotes and swapping between providers can help you get a lower premium in the Australian market.
Other ways to manage premiums without cutting cover
Instead of lowering the sum insured and risking underinsurance, Mr Graham points to other ways to reduce premiums. One option is increasing your excess—the amount you pay out of pocket when you make a claim—which can bring a substantial premium down to something more reasonable.
For people struggling to get insurance, Mr Graham says it could be worth talking to an insurance broker.
What to check at renewal time
Renewal is often the moment when underinsurance can either be corrected—or accidentally locked in for another year. A focused review can help ensure the cover still matches real costs. Based on the expert guidance and definitions above, key checks include:
Confirm your “sum insured” reflects current rebuild and replacement costs, not an outdated estimate.
Use insurer-provided online rebuild calculators and contents calculators as a starting point.
Review your cover annually and always after renovations or additions.
Check whether your policy includes a coinsurance or averaging clause and understand how it could affect a payout if you are underinsured.
Consider whether you are missing key cover types, such as contents insurance, or whether you are uninsured for specific scenarios such as flood or fire.
Compare multiple quotes—Mr Graham suggests four or five—and consider using an independent comparison website to help.
If premiums are difficult to manage, explore alternatives such as adjusting the excess rather than reducing cover.
Planning ahead when buying a home
Insurance affordability can also be an important consideration before you even move in. Dr Huang recommends checking insurance costs when you are looking to buy a home. In high-risk areas, she says, insurance might be a significant expense. Understanding those costs early can help buyers avoid surprises and make more informed decisions about ongoing expenses.
A final word on financial resilience
Underinsurance is often not the result of a single decision, but a gradual mismatch between cover and real costs—driven by changing construction prices, inflation, renovations, and the natural tendency to underestimate replacement costs. The impact, however, can be immediate and severe when a major claim occurs.
For many households, the purpose of home and contents insurance is to protect against losses they cannot easily absorb. Keeping sums insured aligned with realistic rebuild and replacement costs, understanding policy clauses that can reduce payouts, and shopping around for value are practical steps that can reduce the risk of being left significantly out of pocket.
This article contains general information only. You should consider obtaining independent professional advice in relation to your particular circumstances.