Our Methodology

Water Heater Installation Guide uses a desk-research basis. That means we compare published sources and organise the evidence into practical decision pages. We do not claim lab testing, physical product testing or installer performance testing unless a future methodology file explicitly documents that work.

Scoring Dimensions

Product pages use five dimensions from the site config: capacity fit, efficiency, warranty, price and install complexity. These dimensions are designed for water heater purchase decisions where the installed project can matter more than the product box.

Sources Used

The pilot fact sheet uses cost guides, official government pages, local permit examples, manufacturer pages, retailer listings and public homeowner demand signals. Product specifications must be in `_reference/product-claims.json` before they are used in visible copy.

What Desk Research Does Not Mean

Desk research does not mean we installed the units, measured lab performance or verified every local code requirement. It means we checked the published source set, excluded unsupported claims and made limitations visible where the evidence is broad or local.

Update Cadence

Update reviews should prioritise cost ranges, IRS and ENERGY STAR incentive guidance, permit examples, manufacturer specifications and retailer listing changes. Any claim about current credits, prices, warranty, flow rate, efficiency, capacity, voltage or electrical requirements should be rechecked before reuse.