Researched from published specs, not hands-on tested. Here is exactly what that means.
What we start with
- Your constraint. We begin with a real situation, such as a slope, a north window or a 72-cell tray, instead of a list of popular products.
- Trusted sources. We prefer university extension publications and government data. Where we have to rely on a vendor or a secondary source, we say so.
- Published specifications. We use makers' dimensions, ratings and light data, and we note that these are not independently verified.
- Our own math. We show formulas and state our assumptions, so that you can rerun the numbers yourself.
What we can't tell you
Without physical testing, we can't judge long-term durability, build quality or how easy something is to assemble. We avoid those claims. If we ever do test a product ourselves, the page will clearly label what we tested and how.
Product links
We usually point you to a narrow product search that matches the specification in a guide, rather than ranking one product as the winner. We don't show Amazon prices or customer ratings on our pages. Check the current price, details and reviews on Amazon before you buy.
Corrections and updates
Facts change. If you spot a mistake, tell us and we'll check it. A "Reviewed" date appears on a page only when someone has actually reviewed it.