{
  "slug": "whole-home-load-calc",
  "title": "Whole Home Electrical Load Calculator",
  "heading": "Whole-House Electrical Load Calculator",
  "category": "other",
  "url": "https://www.revenuelab.fyi/toolbox/whole-home-load-calc",
  "summary": "Simplified NEC-style load calc to check your panel capacity.",
  "description": "Approximates the NEC Article 220 standard method for residential electrical load calculations, used by electricians to size a service panel or check whether an existing panel has room for an addition like an EV charger, heat pump, or hot tub. It applies the standard 3 VA per sq ft general lighting load, plus small appliance and laundry circuits, then applies NEC demand factors (only a portion of total connected load is counted after the first 10kVA, since not everything runs simultaneously) before adding the largest single motor load at 125%. This is a planning estimate — an actual panel upgrade or new circuit still requires a licensed electrician's calculation and permit, but it tells you quickly whether you're likely to have headroom or need a service upgrade.",
  "formula": "General load = 3VA×sqft + small appliance/laundry circuits; demand factor: 100% of first 10kVA + 40% above; add largest motor at 125%; amps = total VA ÷ 240V.",
  "dateModified": "2026-09-30",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=whole-home-load-calc",
  "inputs": [
    {
      "id": "sqft",
      "label": "House square footage",
      "kind": "number",
      "hint": null,
      "default": 2200,
      "unit": "sq ft",
      "min": 500,
      "max": null
    },
    {
      "id": "smallApplianceCircuits",
      "label": "Small appliance/laundry circuits (usually 3)",
      "kind": "number",
      "hint": null,
      "default": 3,
      "unit": null,
      "min": 1,
      "max": 6
    },
    {
      "id": "fixedAppliances",
      "label": "Fixed appliance load (range, dryer, water heater, etc.)",
      "kind": "number",
      "hint": null,
      "default": 15000,
      "unit": "VA",
      "min": 0,
      "max": null
    },
    {
      "id": "hvacVA",
      "label": "HVAC/heat load",
      "kind": "number",
      "hint": null,
      "default": 8000,
      "unit": "VA",
      "min": 0,
      "max": null
    },
    {
      "id": "largestMotorVA",
      "label": "Largest single motor (e.g., AC compressor)",
      "kind": "number",
      "hint": null,
      "default": 4000,
      "unit": "VA",
      "min": 0,
      "max": null
    },
    {
      "id": "panelAmps",
      "label": "Existing panel size",
      "kind": "number",
      "hint": null,
      "default": 200,
      "unit": "A",
      "min": 60,
      "max": 400
    }
  ],
  "outputs": [
    {
      "id": "amps",
      "label": "Calculated load (amps)",
      "format": "number",
      "hint": null,
      "primary": true
    },
    {
      "id": "headroomAmps",
      "label": "Headroom vs your panel",
      "format": "number",
      "hint": null,
      "primary": false
    },
    {
      "id": "percentUsed",
      "label": "Percent of panel capacity used",
      "format": "percent",
      "hint": null,
      "primary": false
    },
    {
      "id": "totalVA",
      "label": "Total calculated load (VA)",
      "format": "number",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "House square footage: 2200 sq ft",
      "Small appliance/laundry circuits (usually 3): 3",
      "Fixed appliance load (range, dryer, water heater, etc.): 15000 VA",
      "HVAC/heat load: 8000 VA",
      "Largest single motor (e.g., AC compressor): 4000 VA",
      "Existing panel size: 200 A"
    ],
    "outputs": [
      "Calculated load (amps): 106",
      "Headroom vs your panel: 94",
      "Percent of panel capacity used: 53%",
      "Total calculated load (VA): 25,440"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter house square footage (sq ft).",
      "Enter small appliance/laundry circuits (usually 3).",
      "Enter fixed appliance load (range, dryer, water heater, etc.) (VA).",
      "Enter hvac/heat load (VA).",
      "Enter largest single motor (e.g., ac compressor) (VA).",
      "Enter existing panel size (A).",
      "Read your calculated load (amps) 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": {
        "sqft": 1300,
        "smallApplianceCircuits": 2,
        "fixedAppliances": 9000,
        "hvacVA": 5000,
        "largestMotorVA": 2500,
        "panelAmps": 120
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "sqft": 2200,
        "smallApplianceCircuits": 3,
        "fixedAppliances": 15000,
        "hvacVA": 8000,
        "largestMotorVA": 4000,
        "panelAmps": 200
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "sqft": 3500,
        "smallApplianceCircuits": 5,
        "fixedAppliances": 24000,
        "hvacVA": 13000,
        "largestMotorVA": 6500,
        "panelAmps": 320
      }
    }
  ],
  "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": "Is this the exact calculation my electrician will use?",
      "a": "It's a simplified version of the NEC standard method (220.82/220.83) that captures the main components — general lighting, small appliance/laundry circuits, fixed appliances, HVAC, and the largest motor at 125%. A licensed electrician's actual permit calculation may include additional nuances (optional method, existing dwelling rules) that shift the number somewhat."
    },
    {
      "q": "How much headroom do I need for an EV charger?",
      "a": "A Level 2 home charger typically draws 30-50 amps continuous, which the NEC requires be calculated at 125% of continuous load (so a 40A charger needs 50A of panel capacity accounted for). If your headroom is under that, you'll need either a load-management device, a circuit downgrade, or a full panel upgrade."
    },
    {
      "q": "Why does the calculation not just add everything up?",
      "a": "Because not every circuit runs at full draw simultaneously — your dryer, oven, and AC compressor rarely all run flat-out at the same instant. NEC demand factors statistically account for this diversity, which is why the calculated load is meaningfully lower than the sum of every circuit's breaker rating."
    },
    {
      "q": "When do I actually need a panel upgrade?",
      "a": "If your calculated load is within 10-15% of your panel's rated capacity, or adding a new large load (EV charger, heat pump, hot tub, workshop) would push you over it, a 200A upgrade from 100A or 150A is the common fix — budget $2,500-$5,000 depending on utility service entrance work required."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/generator-sizing-fuel",
    "https://www.revenuelab.fyi/toolbox/home-charger-payback",
    "https://www.revenuelab.fyi/toolbox/inverter-sizing"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — Whole Home Electrical Load Calculator (https://www.revenuelab.fyi/toolbox/whole-home-load-calc)"
}