{
  "slug": "insulation-calculator",
  "title": "Insulation Calculator",
  "heading": "Insulation R-Value & Batt Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/insulation-calculator",
  "summary": "Bags, batts, and estimated heating savings by R-value.",
  "description": "Going from R-19 to R-49 in an attic cuts conductive loss through that surface by roughly 60%. The upgrade usually pays back fastest in cold, high-fuel-cost climates.",
  "formula": "Batts = area ÷ coverage per bag; loss ∝ 1 ÷ R-value.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=insulation-calculator",
  "inputs": [
    {
      "id": "area",
      "label": "Area to insulate",
      "kind": "number",
      "hint": null,
      "default": 1200,
      "unit": "sq ft",
      "min": 10,
      "max": null
    },
    {
      "id": "current",
      "label": "Current R-value",
      "kind": "number",
      "hint": null,
      "default": 19,
      "unit": null,
      "min": 0,
      "max": 60
    },
    {
      "id": "target",
      "label": "Target R-value",
      "kind": "number",
      "hint": null,
      "default": 49,
      "unit": null,
      "min": 5,
      "max": 80
    },
    {
      "id": "coverage",
      "label": "Coverage per bag/bundle",
      "kind": "number",
      "hint": null,
      "default": 40,
      "unit": "sq ft",
      "min": 5,
      "max": null
    },
    {
      "id": "price",
      "label": "Price per bag/bundle",
      "kind": "number",
      "hint": null,
      "default": 48,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "heat",
      "label": "Annual heating + cooling bill",
      "kind": "number",
      "hint": null,
      "default": 1600,
      "unit": "$",
      "min": 0,
      "max": null
    }
  ],
  "outputs": [
    {
      "id": "bags",
      "label": "Bags / bundles needed",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "cost",
      "label": "Material cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "savings",
      "label": "Estimated annual savings",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "payback",
      "label": "Payback (years)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "reduction",
      "label": "Heat loss reduction (%)",
      "format": "decimal",
      "hint": null,
      "primary": false
    },
    {
      "id": "tenYear",
      "label": "10-year net",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Area to insulate: 1200 sq ft",
      "Current R-value: 19",
      "Target R-value: 49",
      "Coverage per bag/bundle: 40 sq ft",
      "Price per bag/bundle: 48 $",
      "Annual heating + cooling bill: 1600 $"
    ],
    "outputs": [
      "Bags / bundles needed: 30",
      "Material cost: $1,440",
      "Estimated annual savings: $343",
      "Payback (years): 4.2",
      "Heat loss reduction (%): 61.2",
      "10-year net: $1,989"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter area to insulate (sq ft).",
      "Enter current r-value.",
      "Enter target r-value.",
      "Enter coverage per bag/bundle (sq ft).",
      "Enter price per bag/bundle ($).",
      "Enter annual heating + cooling bill ($).",
      "Read your bags / bundles needed on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "area": 720,
        "current": 11,
        "target": 29,
        "coverage": 25,
        "price": 29,
        "heat": 950
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "area": 1200,
        "current": 19,
        "target": 49,
        "coverage": 40,
        "price": 48,
        "heat": 1600
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "area": 1920,
        "current": 30,
        "target": 78,
        "coverage": 65,
        "price": 77,
        "heat": 2550
      }
    }
  ],
  "limitations": [
    "Estimates assume standard, average conditions — local rules, pricing, and materials vary.",
    "Results are rounded for readability; add a buffer before ordering, booking, or committing.",
    "Double-check anything with a real cost attached against a local quote."
  ],
  "faq": [
    {
      "q": "How does the insulation r-value & batt calculator work?",
      "a": "Going from R-19 to R-49 in an attic cuts conductive loss through that surface by roughly 60%. The upgrade usually pays back fastest in cold, high-fuel-cost climates. The underlying maths is: Batts = area ÷ coverage per bag; loss ∝ 1 ÷ R-value."
    },
    {
      "q": "What do I need to enter?",
      "a": "6 values: area to insulate, current r-value, target r-value, coverage per bag/bundle, price per bag/bundle, and annual heating + cooling bill. Each field starts with a sensible default, so you can change one number at a time and watch the result move."
    },
    {
      "q": "What does the bags / bundles needed result mean?",
      "a": "It is returned as a whole number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds."
    },
    {
      "q": "Is this calculator free, and do I need an account?",
      "a": "Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser."
    },
    {
      "q": "How accurate is the result?",
      "a": "It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary."
    },
    {
      "q": "Who is this tool for?",
      "a": "It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/drywall-calculator",
    "https://www.revenuelab.fyi/toolbox/hvac-run-cost"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Insulation Calculator (https://www.revenuelab.fyi/toolbox/insulation-calculator)"
}