{
  "slug": "generator-vs-battery-backup",
  "title": "Generator vs Battery Backup Calculator",
  "heading": "Generator vs Battery Backup Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/generator-vs-battery-backup",
  "summary": "Compare upfront cost, fuel, and maintenance of a standby generator against a battery + solar backup.",
  "description": "A standby generator costs less upfront and can run indefinitely on fuel, but requires ongoing maintenance and fuel costs during outages. A battery backup system costs more upfront, runs silently with no fuel, but has limited runtime unless paired with solar. This tool compares total cost of ownership over a chosen number of years, factoring in purchase/install price, annual maintenance, and estimated fuel or charging cost per outage.",
  "formula": "Generator TCO = Install Cost + (Annual Maintenance × Years) + (Fuel Cost per Outage × Outages/yr × Years). Battery TCO = Install Cost + (Replacement/Maintenance × Years).",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=generator-vs-battery-backup",
  "inputs": [
    {
      "id": "genInstall",
      "label": "Generator install cost",
      "kind": "number",
      "hint": null,
      "default": 6000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "genMaintAnnual",
      "label": "Generator annual maintenance",
      "kind": "number",
      "hint": null,
      "default": 250,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "fuelPerOutage",
      "label": "Fuel cost per outage",
      "kind": "number",
      "hint": null,
      "default": 60,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "outagesPerYear",
      "label": "Outages per year",
      "kind": "number",
      "hint": null,
      "default": 4,
      "unit": null,
      "min": 0,
      "max": null
    },
    {
      "id": "battInstall",
      "label": "Battery backup install cost",
      "kind": "number",
      "hint": null,
      "default": 12000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "battMaintAnnual",
      "label": "Battery annual maintenance/amortized replacement",
      "kind": "number",
      "hint": null,
      "default": 150,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "years",
      "label": "Years",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": null,
      "min": 1,
      "max": 25
    }
  ],
  "outputs": [
    {
      "id": "winner",
      "label": "Lower total cost option",
      "format": "raw",
      "hint": null,
      "primary": true
    },
    {
      "id": "genTotal",
      "label": "Generator total cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "battTotal",
      "label": "Battery backup total cost",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "diff",
      "label": "Difference",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Generator install cost: 6000 $",
      "Generator annual maintenance: 250 $",
      "Fuel cost per outage: 60 $",
      "Outages per year: 4",
      "Battery backup install cost: 12000 $",
      "Battery annual maintenance/amortized replacement: 150 $",
      "Years: 10"
    ],
    "outputs": [
      "Lower total cost option: Generator",
      "Generator total cost: $10,900",
      "Battery backup total cost: $13,500",
      "Difference: $2,600"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter generator install cost ($).",
      "Enter generator annual maintenance ($).",
      "Enter fuel cost per outage ($).",
      "Enter outages per year.",
      "Enter battery backup install cost ($).",
      "Enter battery annual maintenance/amortized replacement ($).",
      "Enter years.",
      "Read your lower total cost 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": {
        "genInstall": 3600,
        "genMaintAnnual": 150,
        "fuelPerOutage": 35,
        "outagesPerYear": 2,
        "battInstall": 7200,
        "battMaintAnnual": 100,
        "years": 6
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "genInstall": 6000,
        "genMaintAnnual": 250,
        "fuelPerOutage": 60,
        "outagesPerYear": 4,
        "battInstall": 12000,
        "battMaintAnnual": 150,
        "years": 10
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "genInstall": 9600,
        "genMaintAnnual": 400,
        "fuelPerOutage": 95,
        "outagesPerYear": 6,
        "battInstall": 19200,
        "battMaintAnnual": 250,
        "years": 16
      }
    }
  ],
  "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": "Which lasts longer during a multi-day outage?",
      "a": "A fueled generator can run as long as fuel is available, while a battery-only system without solar will deplete in hours to a day depending on load — pairing batteries with solar closes that gap."
    },
    {
      "q": "Is a battery backup quieter and lower maintenance?",
      "a": "Yes — no combustion, no oil changes, no annual exercise cycles required, which is why upfront cost is higher but ongoing cost is lower."
    },
    {
      "q": "Can I combine both?",
      "a": "Many homes run a battery for short outages and quiet operation with a generator as backup for extended outages — this calculator compares them as standalone choices."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/generator-sizing-fuel",
    "https://www.revenuelab.fyi/toolbox/battery-backup-runtime"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Generator vs Battery Backup Calculator (https://www.revenuelab.fyi/toolbox/generator-vs-battery-backup)"
}