Editorial policy
The calculation does not know who pays us.
Backup Power Finder separates manufacturer specifications, planning estimates, observed tests, and commercial relationships so readers can judge each claim on the right evidence.
Calculations
The runtime model uses visible inputs and disclosed formulas. Merchant compensation, product price, and brand do not change the result.
Specifications
Model-specific specifications must come from a current label or manufacturer manual and remain labeled as manufacturer-provided information.
Observed tests
A test must identify the exact unit, load, conditions, starting state, elapsed time, and ending state. A test result applies to that setup, not every owner or environment.
Corrections
Material factual or calculation errors are corrected in the page. Updated assumptions are dated and do not silently rewrite an earlier observed result.
Commercial disclosure
Commissionable links, free products, sponsorships, loans, discounts, and other material brand connections are disclosed clearly near the relevant recommendation or test.
Safety boundary
The portable calculator does not design fixed wiring, transfer equipment, rooftop arrays, backfeeding, or life-safety systems. Whole-home pages prepare questions for appropriately licensed professionals.
No affiliate program is active, no tracking link is installed, no product has been supplied for review, and no sponsor has approved or influenced the calculator or guide library.