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Home & UtilitiesGenerated accuracy model review: 2026-05-06

HVAC Filter Replacement Calculator accuracy and testing

This page documents how Calwarden builds trust for this calculator: source notes, regression-style default tests, limitations, assumptions, unit handling, rounding, and visible change history.

Formula source

  • Changes per year = 12 / interval months. Annual cost = changes x filters per change x filter price + time value.

Test cases

Default input regression check

Generated from the checked-in default inputs and calculate function.

Inputs

  • Filters per Change: 2 filters
  • Replacement Interval: 3 months
  • Price per Filter: $18
  • Time per Change: 10 min
  • Hourly Time Value: 0 $/hr

Expected outputs

  • Annual Filter Cost: $144.00
  • Filters per Year: 8
  • Changes per Year: 4
  • Annual Time Value: $0.00

Known limitations

  • This page documents the checked-in calculator logic and does not certify results for every real-world edge case.
  • Use the result as a planning estimate unless the calculator page states a stricter purpose.

Assumptions

  • All prices, rates, taxes, and usage values are entered by the user.
  • Calculations run locally in your browser and are not stored by Calwarden.
  • This is planning math, not financial, tax, engineering, or legal advice.

Unit handling

  • Filters per Change accepts values in filters.
  • Replacement Interval accepts values in months.
  • Price per Filter accepts values in $.
  • Time per Change accepts values in min.
  • Hourly Time Value accepts values in $/hr.
  • Annual Filter Cost is displayed as currency.
  • Annual Time Value is displayed as currency.

Rounding rules

  • Number displays use up to 2 decimal places in the calculator UI.
  • Currency outputs are displayed with standard US dollar formatting.
  • Input precision follows configured step values where provided.

Version history

1.0.0 - 2026-05-06

Generated accuracy and testing page from the current hvac-filter-replacement-calculator calculator definition.

Change log

2026-05-06

Published default regression test documentation and metadata fallbacks for HVAC Filter Replacement Calculator.

Calculator transparency

Accuracy pages are generated from checked-in calculator definitions and can be upgraded with curated review metadata over time.

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