A city index can summarize a market path. It cannot calculate the equity, profit, or proceeds of a particular homeowner.
The difference between two ZHVI levels can look like a homeowner gain. In this six-city comparison, the modeled dollar changes ranged from $68,705.76 in Chicago to $433,390.52 in Hinsdale.
Those are index differences, not equity statements.
The dollar changes answer a narrow question
Between January 2020 and August 2026, the all-homes ZHVI changes were approximately $68,706 for Chicago, $191,423 for Elmhurst, $433,391 for Hinsdale, $195,130 for Glen Ellyn, $314,366 for Western Springs, and $237,475 for Clarendon Hills.
The calculation subtracts each city's January index level from its August index level. It does not follow an individual property, establish a purchase date, or account for a home's condition and improvements.
Equity depends on more than market value
Homeowner equity generally depends on a property's current value and debt secured by it. A household's economic result can also involve the original purchase price, down payment, principal reduction, financing costs, taxes, insurance, maintenance, improvements, transaction costs, and any credits or concessions.
None of those household fields appears in a city ZHVI row. Even if a property moved exactly with the index, the index change alone would not calculate net sale proceeds or investment return.
Purchase timing also changes the household result. A homeowner who bought before January 2020, during the period, or near the August 2026 endpoint would have a different holding period from the study. A refinance or additional borrowing can change debt without changing the city's index. Improvements can change the subject property without appearing as a separable line in the city series. Those are property and household facts, not corrections that can be inferred from the broad index.
Percentage and dollar change rank the sample differently
Western Springs had the largest percentage change at 52.60%, while Hinsdale had the largest modeled dollar change because its starting index level was higher. That is not a contradiction. Dollar and percentage change use different denominators.
The useful practice is to name the measure. Use percentage change to compare relative movement from each city's own baseline. Use dollar change to describe the difference between two index levels. Use property and financing records for equity.
Source and method: Zillow smoothed, seasonally adjusted city all-homes ZHVI. Dollar change equals August 2026 ZHVI minus January 2020 ZHVI. Read the full six-city study for exact source rows, formulas, and limits.