What happens if you underinsure your home or contents?
You may receive substantially less than you claim for, even on a small claim — and the mechanism that does this catches people badly off guard.
It is called the average clause (or condition of average), and it appears in most home and commercial policies. If you have insured for less than the true value at risk, the insurer reduces every settlement in proportion to how far you were underinsured.
A worked example. Your contents are genuinely worth £60,000; you insured for £30,000 — half the correct figure. You suffer a £4,000 escape-of-water claim, well within your sum insured. Under average, the insurer pays £2,000. You were insured for 50% of the value, so you are treated as having covered 50% of every loss. Nothing about the claim exceeded your limit; the proportionate reduction applies anyway.
Why underinsurance is so common:
Contents are systematically underestimated. Most people guess, and most guesses are far too low. A room-by-room inventory almost always produces a much larger figure than the estimate — clothing, kitchen equipment, tools, bedding and books add up quickly.
Buildings sums insured are the rebuild cost, not the market value. These are different numbers and can diverge dramatically in either direction. Rebuild costs include demolition, professional fees and building to current regulations.
Neither is updated. Home improvements, an extension, or a new kitchen change the figure, and inflation in building costs has been severe.
What to do: use a rebuild cost calculator for buildings rather than guessing, do an actual room-by-room contents inventory, review after any significant purchase or renovation, and check whether high-value items need specifying separately — most policies cap individual items unless listed.