How CostPreview builds an estimate
CostPreview produces planning ranges, not contractor quotes. This page documents the sources, geography, adjustments, and known limits behind the nationwide estimators.
1. Start with a published benchmark
Window replacement and kitchen remodeling use the 2025 JLC/Zonda Cost vs. Value report. Lawn service uses Angi's published U.S. lawn-mowing range. Each result names its source and data vintage. CostPreview is not affiliated with either publisher.
2. Map the ZIP to a local market
The five-digit ZIP is matched to Census ZIP Code Tabulation Area data, then to a county and an Office of Management and Budget metropolitan area where one applies. When a ZIP does not map to a covered metro, the model uses the state as a broader fallback. The raw ZIP is used to calculate the response and is not placed in analytics events.
3. Apply regional prices to the labor-sensitive share
The model uses the U.S. Bureau of Economic Analysis 2024 Regional Price Parities. It does not multiply the entire project by a local index: materials sold nationally and local labor do not respond equally to regional prices. The modeled labor-sensitive shares are 50% for windows, 55% for kitchens, and 82% for lawn service.
4. Adjust the project details
Window estimates scale the ten-window benchmark by count and frame-material factor. Kitchen estimates use a distinct benchmark for minor midrange, major midrange, and major upscale scopes. Lawn estimates apply tapered yard-size scaling and separate factors for mowing, mow-edge-blow, and full-service visits.
What the model cannot know
- Current contractor availability, route density, minimum charges, or a provider's margin.
- Site conditions such as access, damage, unusual dimensions, structural work, or permits.
- Exact products, finish selections, warranties, scheduling constraints, or negotiated discounts.