Insulation/HVAC BTU Load Estimator (Rule of Thumb)

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Everyday & Life

Tranche

tranche-5

Evidence ID

t5-111

Ledger rows

1

No ledger note is attached.

Review findings

NEEDS_REVIEW because the exact climate-factor table, all modifier values and formulas, occupant input handling, area units, and suggested-unit-size mapping are unspecified. The four vectors use an explicitly illustrative convention only: base factors of 20/25/30 BTU/hr/sq ft, supplied multiplicative modifiers, and ceiling modifier equal to ceiling_height_ft/8. This convention is not established by the instrument specification and must not be treated as a validated HVAC method.

Formula and scope findings

• The formula is only a schematic: no actual climate-zone base-factor table is supplied, so the calculation is not reproducible or verifiable.
• Insulation, sun-exposure, ceiling-height, and occupant modifier values and combination rules are unspecified.
• The inputs list omits occupants even though occupants are named as a modifier.
• No formula or sizing rule is supplied for the claimed suggested unit size range.
• A single 20-30 BTU/sq ft baseline is not universally valid for heating and cooling, and heating and cooling loads normally require separate calculations.

Unit assumptions

• BTU requirement means BTU/hr, although the formula should label the output explicitly as BTU/hr.
• Room area is assumed to be in square feet when multiplied by BTU/sq ft.
• The illustrative vectors use ceiling height in feet and a normalized 8-foot reference height.
• The illustrative vectors use multiplicative insulation, sun, ceiling, and occupant modifiers.
• For the metric conversion vector, 1 m² = 10.7639 sq ft.
• The supplied rule-of-thumb factors are treated as heuristic values, not code-compliant or Manual J results.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The estimator overflows to Infinity for an extreme but numerically representable area, and its result is convention-sensitive because the specification does not define whether sun exposure raises cooling load or lowers heating load, whether ceiling height is in feet or metres, or how BTU/hr maps to a suggested unit-size range.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "area_sq_ft": 400,
    "climate_zone": "mild",
    "base_factor_btu_per_sq_ft": 20,
    "insulation_modifier": 0.9,
    "sun_exposure_modifier": 0.9,
    "ceiling_height_ft": 8,
    "ceiling_reference_ft": 8,
    "ceiling_modifier": 1,
    "occupants": 2,
    "occupant_modifier": 1
  },
  "expected_outputs": {
    "estimated_btu_per_hr": 6480,
    "suggested_unit_size_range": null
  },
  "working": "400 sq ft × 20 BTU/hr/sq ft = 8,000 BTU/hr; 8,000 × 0.9 insulation = 7,200; 7,200 × 0.9 sun exposure = 6,480; 6,480 × 1 ceiling modifier × 1 occupant modifier = 6,480 BTU/hr. Suggested unit range cannot be computed because no sizing-range rule is supplied."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json · VERIFIED_CLEAN
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json