How we estimate costs
Every estimate on this site is assembled from its parts rather than copied from another cost guide, and every number links back to where it came from.
Where the numbers come from
- Equipment prices: current retail listings, recorded with the product, the price and the date we checked it.
- Labor by state: a national price is adjusted using U.S. Bureau of Labor Statistics wage data (OEWS, May 2025) for the trade that actually does the work — plumbers, roofers, carpenters, sheet metal workers or HVAC technicians.
- Installed prices and add-ons: published cost guides and contractor price lists. Where we can, each figure has two or more independent sources, and our ranges are widened to cover where they disagree.
Some trades don't price by wages. Foundation repair tracks soil and local contractor markets, and garage door springs are quoted as all-in service prices, so those calculators don't apply a state wage adjustment. Each page says so.
How we check our work
Before a page goes live, its typical job — a like-for-like water heater swap, ten vinyl windows, a standard roof — must land inside independently published benchmark ranges. These checks run automatically every time the site is rebuilt. When a check failed during our review, we fixed the model rather than the benchmark: for example, our roof calculator was counting old-roof removal twice, which we found and corrected this way.
Prices are refreshed on a schedule. A page whose price data is more than 45 days old is automatically taken out of search indexes until it is updated.
What these estimates are not
- They are not quotes. Your home, local codes and your contractor all change the real price.
- They have not yet been reviewed by licensed tradespeople, and each page says so. When a page has been reviewed by one, it will name them.
- They are not a substitute for a structural engineer, electrician or other licensed professional where safety is involved.
How this site is produced
Research, calculations and drafting on this site are done with the help of AI tools, then checked against the cited sources and the automated benchmark tests described above. We publish the sources and a changelog on every page so you can check our work yourself.
Found a mistake?
If a price looks wrong for your area or a source has changed, we want to know. Contact us — every correction is recorded in the changelog of the page it affects. See also our Disclaimer.