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How the data works

Updated Nov 3, 2026

Where the numbers come from

Every local number on this site comes from a homeowner who reported what they paid for an installed standby generator. Reports include the ZIP code, generator size, fuel, transfer switch type, install month and total paid, plus optional itemized parts.

Verification and review

  • Every report needs an email address. We send a 6-digit code, and the report only moves forward once the code is entered.
  • A person reviews every verified report before it counts. We look for duplicates, typos, implausible numbers and installer self-promotion.
  • Automatic checks flag possible duplicates (same email, or same ZIP and a total within 2%, within 30 days), sales wording or contact details in notes, and totals far outside the rest of a state once it has enough reports. Flags only help the reviewer; they never publish or reject anything on their own.

How we match your search

We look for approved reports in your 3-digit ZIP area with the same size band and fuel. If there are fewer than 3, we widen to your state. If your state has fewer than 3 too, we show published cost ranges instead and say so. The transfer switch type and gas-line run are shown for context but don't filter results yet, because early on there are too few reports to split that finely.

Size bands are: up to 14 kW, 15–20 kW, 21–24 kW, and 25 kW and up.

The 3-report minimum

We never show a median, range or part cost for fewer than 3 approved reports. That applies to search results, each part row, and location pages, which only exist once an area has 3 or more reports. Medians and quartiles are rounded to the nearest $10.

Published ranges

Where we don't have enough reports, we show cost ranges from established cost publishers and official fee schedules. Each range is copied exactly from a page we opened, with a link and the date we checked it. We skip sites that look like they exist mainly to collect leads. Most published ranges are national, so they're a rough guide only.

Privacy

We show reports at city or 3-digit ZIP level only. We never publish names, emails, phone numbers, street addresses or full ZIP codes, and notes are only seen by reviewers. See our privacy page.

ZIP code data

ZIP-to-city lookups use postal code data from GeoNames, licensed under CC BY 4.0.

Corrections

Spot something wrong? Email hello@generatorcostcheck.com.