Site information
Data Notes
How 51828 separates transparent estimate modeling, official context sources, illustrative project scenarios, and local written contractor quotes.
Update history
Page maintenance log
Added clearer separation between calculator modeling, official context sources, market references, quote examples, and illustrative project files.
Readers should understand what data is modeled, what is sourced, and what is not a real customer record.
Data transparency review and quote-sample workflow rollout.
51828 Cost Research Desk. Maintained by lengyan.
Found an outdated source, unclear formula, or useful quote example? Send the page URL and details to wwang@51828.com.
What the calculator numbers are
51828 calculator outputs are planning ranges. They are built from a visible model: base project fee, size unit, scope multiplier, scheduling factor, and location factor. They are not scraped contractor bids and they are not guaranteed prices.
What official sources are used for
Official sources such as BLS OEWS, BLS PPI, Census permit data, FTC consumer guidance, EPA safety guidance, DOE energy resources, IRS energy credit pages, and state licensing agencies support context. They help explain labor-market background, material-price context, consumer risk, safety, licensing, permitting, or incentive checks. They do not directly set a homeowner's final quote.
What external market references are used for
Some guide pages include linked market price references from public cost guides. These references are paraphrased into short benchmark notes so readers can compare a contractor quote against an outside range. 51828 does not copy those pages, present them as customer invoices, or treat them as a substitute for local written bids.
What submitted quote examples are used for
Submitted quote examples are used only after personal details are removed and the written scope is clear. Published summaries should show city, state, project size, quote total, quote month, included items, and exclusions. Raw invoices are not published.
See the quote data review page or submit an anonymous quote example.
Maintainer data handling
- Calculator values are treated as planning models, not guaranteed prices or scraped contractor bids.
- Official sources are used for consumer, safety, licensing, energy, tax, permit, and labor-market context, not as direct quote totals.
- Public market references are paraphrased into short benchmark notes and linked to the original pages.
- Reader-submitted quote examples should remove names, addresses, phone numbers, contractor identifiers, and other personal details before review.
- Corrections are checked against the visible model, source library, related pages, and the homeowner decision task before changes are published.
Illustrative project files
Project files and quote breakdowns are editorial examples built from the calculator assumptions. They are included to show what line items to ask about, not to claim a real customer paid that exact amount.
How to improve a page
The strongest correction includes a page URL, city or state, project size, written quote line items, date, and whether the quote included permits, disposal, warranty, and cleanup. Personal information should be removed before sending examples.