Editorial policy
How OwnerSpec decides what to publish, where the numbers come from, how we correct mistakes and how commission is kept out of recommendations.
- Updated
- 4 min read
This site sells nothing and installs nothing. Its only asset is that its numbers can be checked. This page is how we intend to keep it that way.
Where numbers come from
In order of preference:
- Regulations and standards. Published limits and test methods, cited by their number (for example an EPA maximum contaminant level, or an NSF/ANSI standard), never paraphrased into “experts recommend”.
- Manufacturer documentation. Specification sheets, installation manuals and performance data sheets, linked to the document rather than to a shop page.
- Independent testing and academic literature, where it exists.
Retailer listings and marketing pages are used for price and availability only, never as the source of a technical figure.
What we never do
- We do not claim to have tested what we have not tested. No invented bench tests, no photographs of products we do not own, no “we spent 60 hours testing” unless we did. If a page is a synthesis of documentation and published testing, it says so.
- We do not publish a review schema rating we did not earn. Star ratings that exist only to win a search result are misinformation with a gold star on it.
- We do not invent statistics. Every figure is either sourced or shown with its formula.
- We do not accept payment for coverage, placement or a link.
The fact sheet: what every article must expose
At the foot of the page, every article carries a fact sheet built from the same data the page cites. It is written for a reader first and happens to be exactly what an answer engine needs to quote a figure correctly:
| Line | What it holds |
|---|---|
| Answer | One to three sentences with the key number in them |
| Formula, inputs, output | For a calculator: the formula and the worked example it was applied to |
| Basis | For a parts page: the manufacturer document that lists the part. For a review: the published specifications compared. For a guide: the limit and who publishes it |
| Assumptions | Only the assumptions that materially change the answer |
| Method | One sentence on how the answer was produced |
| Primary source | The single document the answer rests on, typed (government, standards body, extension service, manufacturer, research) |
| Facts verified, last updated, canonical URL | The dates, and the one URL to cite |
Every figure in the fact sheet must also appear, with its source, in the body of the page: the build fails a page whose fact sheet states a number the page does not support.
What a review is, and is not
OwnerSpec compares published manufacturer specifications, certification listings and sourced technical documents. Unless a page explicitly states otherwise, OwnerSpec has not laboratory-tested, installed or used the products it compares, and does not own them. Where a page distinguishes a manufacturer’s published figure from an independently certified one (an NSF or WQA listing) it says which is which, and an OwnerSpec calculation is labelled as one. Every page that carries an affiliate link says so above the first paragraph.
Dating and re-verification
Pages that quote prices, fees or regulatory limits carry a “facts verified” date. Bumping that date means someone re-checked the sources on that date. Specifications drift, so an old date is more honest than a fresh one that nobody earned.
Corrections
If something here is wrong, tell us. We fix errors of fact as soon as we can confirm them. Where a correction changes the answer rather than a detail, we say what changed and when at the bottom of the page.
Commission
Some links earn commission. Recommendations are decided before links are added and never reordered to favour a better-paying merchant. The whole arrangement is in our affiliate disclosure.
AI and authorship
Research and drafting tools are used in producing this site. Every published figure is checked against the source cited next to it by a person, and the publisher named in the privacy policy is responsible for what appears here. We do not publish generated text that nobody has verified. Hero images are AI-generated illustrations made for each page: they show the kind of equipment or symptom the page covers and are never a photograph of a unit we tested.
Last updated: 12 September 2026.