{
  "_about": "Every tunable number the System Finder uses. Edit values here; nothing in the code needs to change. Sources are noted beside the numbers they support.",
  "version": "2026-09-phase4",
  "sqft_table": {
    "_source": "ENERGY STAR, 'Room Air Conditioners' product page (energystar.gov/products/room_air_conditioners), table 'Area To Be Cooled (square feet) / Capacity Needed (BTUs per hour)'. Transcribed from the live page on 8 Sep 2026. The ENERGY STAR worked example (147.5 sq ft -> 5,000 BTU) is used as a unit test.",
    "_rows_note": "[area_up_to_sqft, btu_per_hour]. The first row also covers anything under 100 sq ft.",
    "rows": [
      [
        150,
        5000
      ],
      [
        250,
        6000
      ],
      [
        300,
        7000
      ],
      [
        350,
        8000
      ],
      [
        400,
        9000
      ],
      [
        450,
        10000
      ],
      [
        550,
        12000
      ],
      [
        700,
        14000
      ],
      [
        1000,
        18000
      ],
      [
        1200,
        21000
      ],
      [
        1400,
        23000
      ],
      [
        1500,
        24000
      ],
      [
        2000,
        30000
      ],
      [
        2500,
        34000
      ]
    ],
    "beyond_table": {
      "_note": "ENERGY STAR's table is for room air conditioners and stops at 2,500 sq ft. Above that the estimate continues from the last row at this marginal rate. This is RN HVAC Supply's own starting value, NOT an ENERGY STAR figure: the widely used central-system rule of thumb is roughly 400-600 sq ft per ton (about 20-30 BTU per sq ft). Change it here.",
      "from_sqft": 2500,
      "from_btu": 34000,
      "marginal_btu_per_sqft": 20
    }
  },
  "adjustments": {
    "_source_sun": "ENERGY STAR: shaded rooms reduce capacity by 10 percent, sunny rooms increase by 10 percent.",
    "_source_people": "ENERGY STAR: add 600 BTU for each additional person beyond two.",
    "_source_kitchen": "ENERGY STAR: increase capacity by 4,000 BTU for a kitchen.",
    "_source_others": "Insulation, windows and ceiling factors are RN HVAC Supply's own starting values, approved 6 Sep 2026.",
    "ceiling": {
      "reference_height_ft": 8,
      "min_factor": 0.9,
      "max_factor": 1.5,
      "_note": "factor = height / 8, clamped. Lower ceilings reduce the load a little; tall ceilings raise it up to 1.5x."
    },
    "insulation": {
      "poor": 1.15,
      "average": 1.0,
      "good": 0.9,
      "unsure": 1.05
    },
    "windows": {
      "few": 0.95,
      "average": 1.0,
      "many": 1.1
    },
    "sun": {
      "low": 0.9,
      "average": 1.0,
      "high": 1.1
    },
    "per_person_beyond_two_btu": 600,
    "kitchen_btu": 4000,
    "climate": {
      "_note": "IECC climate zone from the customer's ZIP (rn-finder-climate.json: DOE/PNNL county zones joined to ZIP). Two factors: cooling scales the ENERGY STAR area table (which assumes a moderate climate) up in hot zones and down in cold ones; heating is used when the goal includes heating and a heat pump must carry the winter, where cold zones need more capacity, not less. The larger of the two that applies wins. Zone unknown -> default.",
      "default": 1.0,
      "cooling_by_zone": {
        "1": 1.15,
        "2": 1.1,
        "3": 1.05,
        "4": 1.0,
        "5": 0.95,
        "6": 0.92,
        "7": 0.9,
        "8": 0.9
      },
      "heating_by_zone": {
        "1": 1.0,
        "2": 1.0,
        "3": 1.0,
        "4": 1.0,
        "5": 1.05,
        "6": 1.12,
        "7": 1.2,
        "8": 1.25
      },
      "cold_climate_from_zone": 5,
      "_cold_note": "From this zone up, with a heating goal, the finder favours cold-climate (hyper-heat / high-HSPF2) equipment."
    }
  },
  "range": {
    "_note": "The estimate is shown as a range, never a single number. The midpoint is the adjusted table value; min and max are scaled then snapped outward to standard equipment sizes.",
    "min_factor": 0.9,
    "max_factor": 1.15,
    "snap_to_btu": [
      9000,
      12000,
      18000,
      24000,
      30000,
      36000,
      42000,
      48000,
      60000,
      72000,
      90000,
      120000
    ],
    "_snap_note": "min snaps DOWN to the nearest size, max snaps UP. Below the smallest size the range starts at the smallest size."
  },
  "system_type": {
    "_note": "Product-discovery logic, not engineering rules. Keyed on space type, then ductwork answer.",
    "single_room": {
      "none": [
        "mini_split"
      ],
      "ducts": [
        "mini_split"
      ],
      "unsure": [
        "mini_split"
      ]
    },
    "addition": {
      "none": [
        "mini_split"
      ],
      "ducts": [
        "mini_split",
        "central"
      ],
      "unsure": [
        "mini_split"
      ]
    },
    "garage": {
      "none": [
        "mini_split"
      ],
      "ducts": [
        "mini_split"
      ],
      "unsure": [
        "mini_split"
      ]
    },
    "apartment": {
      "none": [
        "mini_split"
      ],
      "ducts": [
        "mini_split"
      ],
      "unsure": [
        "mini_split"
      ]
    },
    "multiple_rooms": {
      "none": [
        "multi_split",
        "mini_split"
      ],
      "ducts": [
        "central",
        "multi_split"
      ],
      "unsure": [
        "multi_split",
        "central"
      ]
    },
    "whole_home": {
      "none": [
        "multi_split",
        "ducted_mini_split"
      ],
      "ducts": [
        "central",
        "ducted_mini_split"
      ],
      "unsure": [
        "central",
        "multi_split"
      ]
    },
    "commercial": {
      "none": [
        "mini_split",
        "packaged"
      ],
      "ducts": [
        "packaged",
        "central"
      ],
      "unsure": [
        "mini_split",
        "packaged"
      ]
    },
    "packaged_min_btu": 36000
  },
  "goal": {
    "_note": "How the goal answer filters and sorts candidates.",
    "cooling_only": {
      "require_heat": false,
      "sort": "fit"
    },
    "heating_cooling": {
      "require_heat": true,
      "sort": "fit"
    },
    "heating": {
      "require_heat": true,
      "prefer_cold_climate": true,
      "sort": "hspf2"
    },
    "replace": {
      "require_heat": null,
      "sort": "fit"
    },
    "efficiency": {
      "require_heat": null,
      "sort": "seer2"
    }
  },
  "matching": {
    "btu_tolerance": 0.1,
    "show_min": 3,
    "show_max": 6,
    "complete_system_unit_types": [
      "Complete System",
      "Mini Split System",
      "Single Zone System",
      "Multi Zone System",
      "Packaged Unit",
      "Packaged System"
    ]
  },
  "badges": {
    "_note": "Only badges with a real rule appear. PREMIUM PICK has no rule yet and is intentionally absent.",
    "high_efficiency": {
      "rule": "highest seer2 among the shown matches"
    },
    "best_value": {
      "rule": "lowest price per 1,000 BTU among the shown matches"
    }
  }
}