Reconcile one completed peak-hour hot-water demand with one exact storage or non-flow-activated water-heater model's source-owned First-Hour Rating.
A quick decision brief for this specific tool
One named and revisioned completed storage/non-flow water-heater FHR/demand record; completed peak-hour hot-water demand source, worksheet/report row and responsible reviewer; one exact manufacturer/model identity; exact-model First-Hour Rating source plus label/directory/rating revision and documented rating mode; arithmetic/conversion method; positive demand and FHR independently tagged US gal or L; optional independent completed signed FHR-minus-demand margin with its source and an optional separate reviewer-owned arithmetic tolerance; plus explicit completed-demand, exact non-flow FHR, same-model/revision/mode coherence and arithmetic-only decision boundaries
Normalized completed demand and exact-model First-Hour Rating in US gal and L; signed FHR-minus-demand in both units; neutral FHR/demand arithmetic ratio; optional reported-minus-reproduced margin and inside/outside owner-tolerance state; complete model/source/revision/mode/method/reviewer evidence; deliberate page-session retention, copy/Markdown/print/share actions; and stable Project outputs that keep demand estimation/validation, FHR derivation from tank volume/recovery, instantaneous Maximum-GPM evaluation, product/fuel/tank-volume/quantity selection, temperature/scald/Legionella assessment, plumbing/venting/electrical/gas/control design and code/installation/commissioning/operation approval false
Validate one coherent completed record; preserve independent source units and convert exactly with1 US liquid gal=3.785411784L; subtract normalized completed peak-hour demand from the exact non-flow model's source-owned First-Hour Rating; divide FHR by demand only as neutral arithmetic; then optionally reconcile one independently reported signed same-record margin inside a reviewer-owned arithmetic tolerance without deriving FHR, estimating demand or classifying product suitability
Choose your path
Reconcile one completed peak-hour hot-water demand row with one exact storage/non-flow-activated water-heater model's source-owned First-Hour Rating while preserving model, label/rating revision, documented mode, method and reviewer and without estimating demand, deriving FHR, evaluating tankless GPM, choosing a product, setting temperature or approving installation.
Compare completed demand and exact-model FHR without losing either source, unit, label/revision, documented mode or reviewer.
Name the record and exact model, retain demand/rating/mode/method sources, enter independently tagged US-gallon or litre values, affirm all four evidence/decision boundaries, then reconcile.
Receives normalized values, signed FHR-minus-demand and a neutral ratio while every source and nondecision remains visible.
Compare another completed FHR-minus-demand row without turning arithmetic agreement into product, demand, safety or installation acceptance.
Enter the signed reported margin and source, optionally add the record owner's arithmetic tolerance, inspect reported-minus-reproduced sign, retain a snapshot, edit a live input and verify stale-result removal.
Can distinguish arithmetic agreement from evidence or product approval, with tolerance neutral when absent and retained evidence immutable when the live form changes.
Avoid a purchase size generated from occupant count, fixture stereotypes, recovery defaults, fixed tank lists or tankless GPM guesses.
Load the clearly static example, trigger inferred-demand, wrong-rating, mixed-record and product/safety decision refusals, recover with a coherent completed record, reconcile, retain and Reset.
Unsupported requests fail at their owning field with no stale result/action, and the Tool never recommends fuel, tank volume, product, quantity, temperature, plumbing, venting, electrical/gas work or installation.
Outputs and checklists are planning aids. Review the linked current authorities and the records, terms, instructions, and requirements that apply to your exact situation before a consequential decision.
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Use one already completed peak-hour demand schedule from its responsible workflow. Preserve its source, worksheet or report row, revision and unit. Occupant counts, typical fixture assumptions and partial schedules are refused rather than converted into demand.
Input = source-owned completed peak-hour demandUse the First-Hour Rating attached to one exact storage or other non-flow-activated model and its documented label, directory or rating record. Federal test terminology separates FHR from the Maximum GPM rating used for flow-activated equipment; tank volume and recovery rate are not substitutes.
Rating input = exact-model source-owned FHRNormalize independently entered US gallons or litres, subtract the completed demand from FHR and report the FHR-to-demand ratio. A signed margin is evidence for review, not a product-suitability threshold or purchase decision.
Arithmetic margin = exact-model FHR − completed peak-hour demandUpdated: July 2026
A de-identified schedule records 64 US gal of completed peak-hour demand and one exact non-flow model's label records a 72 US gal FHR. The Tool reproduces an 8 US gal signed margin and a 1.125 arithmetic ratio without recommending that model.
A reviewer enters a completed demand in litres and an exact-model FHR in US gallons. The Tool converts both with the documented US-gallon/litre factor while preserving the original sources, revision and rating mode.
A user supplies household size, tank capacity, recovery rate or a tankless GPM value and asks for a product size. The demand, rating or decision boundary blocks the request instead of inventing an FHR or recommendation.
Bring one completed source-owned peak-hour demand schedule with its revision and row. Do not let this Tool manufacture the demand it later compares.
Use the exact non-flow model's source-owned First-Hour Rating and retain its label/rating revision and mode. Each other quantity needs its own responsible workflow.
Keep product, fuel, tank volume, quantity, temperature, scald/Legionella, plumbing, venting, electrical/gas, code, installation, commissioning and operation decisions with current qualified evidence and responsible professionals.
Reconcile one completed storage-water-heater evidence row. Bring a source-owned peak-hour demand, one exact non-flow-activated model's published First-Hour Rating, its label or rating revision and documented mode, the arithmetic method and a responsible reviewer. The Tool does not estimate demand, derive FHR from tank volume or recovery, evaluate instantaneous Maximum GPM, choose a product, set temperature or approve installation.