The grading is the product.

First, we pin down the exact product.

Model, generation, capacity, pipe size, finish — we lock the exact version before research starts. Reviews that blur two generations or a sibling model together get set aside.

Then we weigh the evidence, in order.

1. Standards bodies, certifiers, recalls, public filings, and real test documents.
2. The manufacturer's manuals, specs, warranties, terms, and support docs.
3. Independent hands-on and instrumented testing.
4. Large sets of owner reviews, read for recurring patterns.
5. Individual reviews and forum posts — as leads, not proof.

Secondary articles and comparison pages can point us toward evidence. A product claim still gets verified against primary or reliable independent sources before we rely on it.

The score

The four verdicts

Safety comes first, always.

A high score can't outweigh an unresolved safety question. If we can't confirm a required safety listing for ourselves, the product can't earn Green until that changes — no matter how well it scores everywhere else.

Money doesn't touch the verdict.

We settle the recommendation first, then look at whether a link even exists. The test we hold ourselves to is simple: would we still send the same buyer to this product if it paid us nothing? If the honest answer is no, the recommendation was never really ours to give.

We keep it current.

Prices and terms move. Every product page carries the date we last checked it, and we recheck when a real claim, a safety detail, a warranty term, or the model itself changes.