How We Build Our Cost Figures
Every price on this site comes from a published, cited source. When no source publishes a figure we need, we make an estimate, label it as an estimate, and show how we got it.
The short version
- Every price on this site comes from a published, cited source: national cost guides, official permit fee schedules, or university extension research.
- When no source publishes a figure we need, we make an estimate, label it as an estimate, and show how we got it.
- The calculators combine those figures with simple, documented arithmetic.
- Each tool and guide shows the month it was last reviewed, and we refresh the tables at least once a year.
- These are planning ranges, not quotes.
This site is published by Cornelia Cove LLC.
1. Where the numbers come from
| Source type | Used for | Examples |
|---|---|---|
| National cost guides | Price ranges, averages, component costs | Angi and HomeAdvisor (same company, same data, counted as one source), This Old House, HomeGuide, Fixr, NerdWallet |
| Official government sources | Permit fees, permit and maintenance rules | State environmental agencies, county and health-district fee schedules, groundwater conservation district rules |
| University extension research | Maintenance intervals, system care | Penn State Extension, Texas A&M AgriLife Extension |
Each calculator and cost guide lists its own sources with links.
2. How figures are chosen
- As published. We copy a source's range exactly. We don't round, blend or “adjust for inflation”.
- One primary source per figure. When several sources publish the same figure, we use the most recently updated page that publishes it. Other sources are cross-checks, and we show the spread when it's large.
- Same numbers everywhere. The calculator, the cost guide, our reports and page titles use the same figures. An automated validation script checks the sites before publishing.
- Estimates are labeled, with their method. If no source publishes a figure the calculator needs, we label it “estimate” on the page and say how it was derived.
3. How the calculators work
All calculators run in your browser from fixed tables. Nothing you enter changes the figures—input values select from pre-set ranges and apply documented arithmetic.
4. How often we update
- Every calculator and cost guide carries a “last reviewed” month.
- We refresh the cost tables at least once a year against the national cost guides listed above, and update the year in page titles at the same time.
- Permit sections show their own “last verified” date.
- Most recent full refresh: October 2026.
5. Limits
- They're national, not local. Except for official permit fees, our ranges are national, and prices in your area can fall outside them.
- They're not quotes. We don't survey contractors. Soil, depth, access, distance and local code all move real prices.
- Sources disagree. We pick one primary source per figure and show the spread when it's large.
- Data ages. Published ranges update on each source's schedule. Check the “last reviewed” date.
- We aren't the regulator. Permit rules here summarize official sources, so confirm with your permitting authority.
6. Reusing our data
- Our cost-report tables are downloadable as CSV and licensed CC BY 4.0.
- You can reuse them with attribution and a link back to the report page.
- Suggested credit: “Source: Walk-In Cooler Repair Pros 2026 Cost Report (Cornelia Cove LLC)”.
7. Corrections
Spot a wrong or outdated figure? Email partners@corneliacove.com. We check reported errors against the cited source and update the page and its review date.