The most common question on a homeowners quote is some version of "why is the house insured for $420,000 when I paid $310,000?" Or the reverse. The answer is that a sale price and a rebuild cost measure different things.
Three numbers that get confused
| Number | What it measures | Who uses it |
|---|---|---|
| Market value | Land + house + location + what buyers will pay right now | Realtors, lenders, buyers |
| Assessed / taxable value | A formula the county uses to set property taxes | Your township |
| Replacement cost | Labor and materials to rebuild the same house on the same lot after a total loss | Your insurance policy |
In rural Northern Michigan, replacement cost is frequently higher than market value: the house would cost more to build than the finished house sells for, because the land is inexpensive and contractors are not. In a hot suburban market the opposite happens: the lot is worth more than the house.
Why it matters
Your dwelling limit is the most your policy will pay to rebuild. If it is set at market value in a place where rebuilding costs more, a total loss leaves you short. Many policies also carry a coinsurance clause: insure for less than 80% of replacement cost and even a partial claim is reduced proportionally.
How the number is estimated
Carriers use a replacement cost estimator: square footage, construction type, roof, number of stories, kitchen and bath quality, garages, decks, and local labor rates. The estimate is only as good as the answers. A finished basement, a standing-seam metal roof, or custom millwork that was never mentioned is coverage that was never bought.
Extended replacement cost
Because estimates are estimates, most good policies add a cushion — commonly 25% to 50% above the dwelling limit — that pays when rebuilding costs more than expected, which after a regional storm is exactly when it does. Ask whether your policy has it and how much.