Insulation/HVAC BTU Load Estimator (Rule of Thumb) implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t5-111

Effect

Computation or source lookup only

Input and validation requirements

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.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "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."
}

Other records

Sources and evidence

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

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json