{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://askcalculators.com/us/heat-loss/schema.json",
  "title": "Room Heat Loss Calculator — United States inputs",
  "description": "Estimate steady-state room heat loss from entered fabric properties, air exchange and a local outdoor design temperature. USD planning view; stated limitations apply.",
  "type": "object",
  "properties": {
    "unitSystem": {
      "title": "Measurement system",
      "type": "string",
      "default": "imperial",
      "enum": [
        "imperial",
        "metric"
      ],
      "x-optionLabels": {
        "imperial": "Imperial (US gallons / short tons where relevant)",
        "metric": "Metric"
      }
    },
    "wallArea": {
      "title": "Exposed opaque wall area",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 538.195520835486,
      "minimum": 0,
      "maximum": 10763910416709.72,
      "x-suffix": "ft²"
    },
    "wallU": {
      "title": "Wall U-value",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 0.05283305514296545,
      "minimum": 0.0017611018380988483,
      "maximum": 1.7611018380988483,
      "x-suffix": "BTU/(h·ft²·°F)"
    },
    "roofArea": {
      "title": "Exposed roof area",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 430.55641666838886,
      "minimum": 0,
      "maximum": 10763910416709.72,
      "x-suffix": "ft²"
    },
    "roofU": {
      "title": "Roof U-value",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 0.035222036761976966,
      "minimum": 0.0017611018380988483,
      "maximum": 1.7611018380988483,
      "x-suffix": "BTU/(h·ft²·°F)"
    },
    "windowArea": {
      "title": "Window and external door area",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 86.11128333367778,
      "minimum": 0,
      "maximum": 10763910416709.72,
      "x-suffix": "ft²"
    },
    "windowU": {
      "title": "Window/door U-value",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 0.24655425733383876,
      "minimum": 0.0017611018380988483,
      "maximum": 3.5222036761976967,
      "x-suffix": "BTU/(h·ft²·°F)"
    },
    "floorArea": {
      "title": "Exposed floor area",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 430.55641666838886,
      "minimum": 0,
      "maximum": 10763910416709.72,
      "x-suffix": "ft²"
    },
    "floorU": {
      "title": "Floor U-value",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 0.04402754595247121,
      "minimum": 0.0017611018380988483,
      "maximum": 1.7611018380988483,
      "x-suffix": "BTU/(h·ft²·°F)"
    },
    "volume": {
      "title": "Heated internal volume",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 3531.466672148859,
      "minimum": 0,
      "maximum": 35314666721488.586,
      "x-suffix": "ft³"
    },
    "airChanges": {
      "title": "Air changes per hour",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 0.5,
      "minimum": 0,
      "maximum": 20,
      "x-step": 0.01
    },
    "insideTemp": {
      "title": "Indoor design temperature",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 68,
      "minimum": 14,
      "maximum": 104,
      "x-suffix": "°F"
    },
    "outsideTemp": {
      "title": "Outdoor design temperature",
      "type": "number",
      "description": "Illustrative starting value; replace with your own evidence.",
      "default": 23,
      "minimum": -112,
      "maximum": 104,
      "x-suffix": "°F"
    }
  },
  "required": [
    "wallArea",
    "wallU",
    "roofArea",
    "roofU",
    "windowArea",
    "windowU",
    "floorArea",
    "floorU",
    "volume",
    "airChanges",
    "insideTemp",
    "outsideTemp"
  ],
  "additionalProperties": false,
  "x-askcalculators": {
    "version": "20.16.0",
    "calculatorUrl": "https://askcalculators.com/us/heat-loss/",
    "queryExample": "https://askcalculators.com/us/heat-loss/?unitSystem=imperial&wallArea=538.195520835486&wallU=0.05283305514296545&roofArea=430.55641666838886&roofU=0.035222036761976966&windowArea=86.11128333367778&windowU=0.24655425733383876&floorArea=430.55641666838886&floorU=0.04402754595247121&volume=3531.466672148859&airChanges=0.5&insideTemp=68&outsideTemp=23",
    "migrationStatus": "new",
    "reviewStatus": "pending",
    "pageStatus": "live",
    "workStatus": "pending",
    "formula": {
      "expression": "heat loss, W = Σ(area × U-value × temperature difference) + 0.33 × air changes × room volume × temperature difference.",
      "note": "Inputs are converted to canonical units before evaluating this stated formula."
    },
    "quality": {
      "availability": "live",
      "technicalReviewRecord": "/reviews/v20-us-heat-loss.json",
      "qualifiedReview": "pending",
      "qualifiedReviewer": null,
      "qualifiedReviewDate": null,
      "formulaVersion": "20.16.0",
      "referenceCoverage": "references-listed",
      "releaseTestScope": "Catalog and regression checks are not a professional formula audit; consult release evidence.",
      "historicalMetadataDate": "",
      "historicalMetadataNotice": "The imported date is not evidence of a completed human review."
    },
    "outputs": {
      "fabricLoss": {
        "title": "Fabric design heat loss",
        "type": "number",
        "x-format": "number",
        "x-digits": 2
      },
      "ventilationLoss": {
        "title": "Ventilation design heat loss",
        "type": "number",
        "x-format": "number",
        "x-digits": 2
      },
      "totalLoss": {
        "title": "Total screening heat loss",
        "type": "number",
        "x-format": "number",
        "x-digits": 2,
        "x-primary": true
      }
    }
  }
}