{
  "slug": "window-replacement-vs-storm-windows",
  "title": "Window Replacement vs Storm Windows Calculator",
  "heading": "Window Replacement vs Storm Windows Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/window-replacement-vs-storm-windows",
  "summary": "Compare full window replacement against adding storm windows for energy savings payback.",
  "description": "Full window replacement is expensive but delivers the biggest efficiency and comfort gain plus resale value. Adding storm windows over your existing windows costs a fraction as much and can capture a meaningful chunk of the energy savings. This calculator compares upfront cost against annual energy savings for each option to find which one pays back faster and saves more over your horizon.",
  "formula": "Payback = Upfront Cost ÷ Annual Energy Savings. Net Savings = (Annual Savings × Horizon) − Upfront Cost.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=window-replacement-vs-storm-windows",
  "inputs": [
    {
      "id": "windowCount",
      "label": "Number of windows",
      "kind": "number",
      "hint": null,
      "default": 12,
      "unit": null,
      "min": 1,
      "max": null
    },
    {
      "id": "replaceCostEach",
      "label": "Full replacement cost per window",
      "kind": "number",
      "hint": null,
      "default": 650,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "stormCostEach",
      "label": "Storm window cost per window",
      "kind": "number",
      "hint": null,
      "default": 150,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "replaceAnnualSavings",
      "label": "Annual energy savings, full replacement",
      "kind": "number",
      "hint": null,
      "default": 350,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "stormAnnualSavings",
      "label": "Annual energy savings, storm windows",
      "kind": "number",
      "hint": null,
      "default": 180,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "horizon",
      "label": "Comparison horizon",
      "kind": "number",
      "hint": null,
      "default": 15,
      "unit": "yrs",
      "min": 1,
      "max": 40
    }
  ],
  "outputs": [
    {
      "id": "winner",
      "label": "Better net savings option",
      "format": "raw",
      "hint": null,
      "primary": true
    },
    {
      "id": "replacePayback",
      "label": "Full replacement payback",
      "format": "duration",
      "hint": null,
      "primary": false
    },
    {
      "id": "stormPayback",
      "label": "Storm windows payback",
      "format": "duration",
      "hint": null,
      "primary": false
    },
    {
      "id": "diff",
      "label": "Net savings difference over horizon",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Number of windows: 12",
      "Full replacement cost per window: 650 $",
      "Storm window cost per window: 150 $",
      "Annual energy savings, full replacement: 350 $",
      "Annual energy savings, storm windows: 180 $",
      "Comparison horizon: 15 yrs"
    ],
    "outputs": [
      "Better net savings option: Storm Windows",
      "Full replacement payback: 22.3",
      "Storm windows payback: 10",
      "Net savings difference over horizon: $3,450"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter number of windows.",
      "Enter full replacement cost per window ($).",
      "Enter storm window cost per window ($).",
      "Enter annual energy savings, full replacement ($).",
      "Enter annual energy savings, storm windows ($).",
      "Enter comparison horizon (yrs).",
      "Read your better net savings option 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": {
        "windowCount": 7,
        "replaceCostEach": 400,
        "stormCostEach": 90,
        "replaceAnnualSavings": 200,
        "stormAnnualSavings": 100,
        "horizon": 9
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "windowCount": 12,
        "replaceCostEach": 650,
        "stormCostEach": 150,
        "replaceAnnualSavings": 350,
        "stormAnnualSavings": 175,
        "horizon": 15
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "windowCount": 19,
        "replaceCostEach": 1050,
        "stormCostEach": 240,
        "replaceAnnualSavings": 550,
        "stormAnnualSavings": 300,
        "horizon": 24
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "Do storm windows really save meaningful energy?",
      "a": "Good storm windows can cut air leakage significantly and capture roughly half the efficiency gain of full replacement at a fraction of the cost, which is why they often win on payback speed."
    },
    {
      "q": "Does full replacement add more resale value?",
      "a": "Yes — new energy-efficient windows are consistently one of the higher ROI home improvements at resale, an advantage storm windows don't provide since old windows remain underneath."
    },
    {
      "q": "Can I do storm windows now and replace later?",
      "a": "Yes, many homeowners use storm windows as a bridge to stop the bleeding on energy costs, then budget for full replacement in a later renovation cycle."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/window-installation-cost-calculator",
    "https://www.revenuelab.fyi/toolbox/window-upgrade-payback"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Window Replacement vs Storm Windows Calculator (https://www.revenuelab.fyi/toolbox/window-replacement-vs-storm-windows)"
}