{
  "schemaVersion": 1,
  "slug": "laundry-cost-calculator",
  "category": "cleaning",
  "kind": "implementation",
  "independentValidation": false,
  "implementationHash": "422bf047868eb8b1d995af61a1a5794fdf843e4a621b9019ecaa9121c1601e5a",
  "provenance": "Generated from the calculation contract used by the published page. Publication is not external validation.",
  "sourceFiles": [
    "data/calculators/laundry-cost-calculator.json",
    "src/engine.js"
  ],
  "runtimeSource": "/sources/engine.txt",
  "runtimeHash": "5c888d8898afbdee36267bb9977829e1e2ac568f6677c8ee87469c139864645c",
  "scope": "The compute function records implemented equations, constants, lookup tables and custom rules. Inputs record defaults and allowed values; outputs record precision and units. Defaults are examples, not recommendations. General background references are not evidence for this specific algorithm.",
  "publishedFormula": {
    "formula": "C = E × p_e + V_w ÷ 1000 × p_w + C_d; E = E_m + E_d",
    "vars": [
      [
        "C",
        "Cost per load at home"
      ],
      [
        "E",
        "Energy per load (kWh, washer + dryer)"
      ],
      [
        "p_e",
        "Electricity rate"
      ],
      [
        "V_w",
        "Water used (gal)"
      ],
      [
        "p_w",
        "Water rate per 1,000 gal"
      ],
      [
        "C_d",
        "Detergent cost per load"
      ]
    ],
    "note": "Annual cost = per-load cost × loads/week × 52; savings = (laundromat price − home cost) × loads/week × 52. Inputs are user estimates."
  },
  "externalEvidence": null,
  "contract": {
    "compute": "const energy = (machineKwh + dryerCost)*electricityRate; const water = waterGallons/1000*waterRate; const perLoad = energy + water + detergentCost; const homeYear = perLoad*loadsPerWeek*52; const laundroYear = laundromatPrice*loadsPerWeek*52; const parts = [['Energy and drying', energy], ['Water', water], ['Detergent', detergentCost]]; parts.sort((a, b) => b[1] - a[1]); return { costPerLoadHome: perLoad, weeklyCostHome: perLoad*loadsPerWeek, annualCostHome: homeYear, annualCostLaundromat: laundroYear, annualSaving: laundroYear - homeYear, costPerLoadBreakdown: parts[0][0], energyCost: energy };",
    "inputs": [
      {
        "name": "loadsPerWeek",
        "type": "number",
        "default": 5,
        "min": 1,
        "max": 100,
        "step": 1,
        "slider": true
      },
      {
        "name": "machineKwh",
        "type": "number",
        "default": 1.3,
        "min": 0.05,
        "max": 20,
        "step": 0.05,
        "slider": true
      },
      {
        "name": "electricityRate",
        "type": "number",
        "default": 0.17,
        "min": 0,
        "max": 10,
        "step": 0.01,
        "slider": true
      },
      {
        "name": "waterGallons",
        "type": "number",
        "default": 20,
        "min": 1,
        "max": 200,
        "step": 1,
        "slider": true
      },
      {
        "name": "waterRate",
        "type": "number",
        "default": 6,
        "min": 0,
        "max": 200,
        "step": 0.1,
        "slider": true
      },
      {
        "name": "detergentCost",
        "type": "number",
        "default": 0.25,
        "min": 0,
        "max": 50,
        "step": 0.01,
        "slider": true
      },
      {
        "name": "dryerCost",
        "type": "number",
        "default": 3.3,
        "min": 0,
        "max": 20,
        "step": 0.1,
        "slider": true
      },
      {
        "name": "laundromatPrice",
        "type": "number",
        "default": 4.5,
        "min": 0,
        "max": 100,
        "step": 0.25,
        "slider": true
      }
    ],
    "outputs": [
      {
        "name": "costPerLoadHome",
        "precision": 3,
        "unit": "$"
      },
      {
        "name": "weeklyCostHome",
        "precision": 2,
        "unit": "$"
      },
      {
        "name": "annualCostHome",
        "precision": 2,
        "unit": "$"
      },
      {
        "name": "annualCostLaundromat",
        "precision": 2,
        "unit": "$"
      },
      {
        "name": "annualSaving",
        "precision": 2,
        "unit": "$"
      },
      {
        "name": "costPerLoadBreakdown",
        "precision": 0,
        "unit": "",
        "type": "text"
      },
      {
        "name": "energyCost",
        "precision": 3,
        "unit": "$"
      }
    ],
    "interpret": null
  }
}