{
 "slug": "heat-pump-share",
 "computed_from": "masspermits.com build",
 "corpus_fetched_at": "2026-08-18T09:33:48.710994+00:00",
 "corpus_rows": 37361,
 "corpus_sources": 31,
 "corpus_first": "2026-02-19",
 "corpus_last": "2026-08-18",
 "method": {
  "heat_pump": "heat\\s*pump|mini[\\s-]?split|minisplit|ductless|\\bashp\\b",
  "fossil": "\\bfurnace(s)?\\b|\\bboiler(s)?\\b|forced hot air|\\bgas heat\\b|oil burner",
  "adu": "\\baccessory dwelling|\\badu\\b|in[- ]law (apartment|suite)|accessory apartment",
  "min_desc_chars": 8,
  "min_heating_rows": 20,
  "min_gas_distinctness": 0.5,
  "min_weekday_rows": 100,
  "min_calendar_fridays": 6
 },
 "guards": {
  "eligible_towns": [
   6,
   null
  ],
  "eligible_n": [
   250,
   null
  ],
  "pooled_share": [
   20.0,
   55.0
  ],
  "excluded_towns": [
   1,
   null
  ],
  "spread": [
   1.4,
   6.0
  ]
 },
 "stats": {
  "eligible_towns": 10,
  "eligible_n": 499,
  "eligible_hp": 177,
  "pooled_share": 35.5,
  "min_share": 20.0,
  "max_share": 46.7,
  "spread": 2.3,
  "excluded_towns": 3,
  "thin_towns": 18,
  "n_sources": 31,
  "excluded_rows": 462,
  "top": {
   "source": "Randolph, MA",
   "n": 60,
   "hp": 28,
   "ff": 32,
   "share": 46.7,
   "gas_rows": 59,
   "gas_distinctness": 0.78
  },
  "bottom": {
   "source": "West Bridgewater, MA",
   "n": 30,
   "hp": 6,
   "ff": 24,
   "share": 20.0,
   "gas_rows": 41,
   "gas_distinctness": 0.93
  },
  "table": [
   {
    "source": "Randolph, MA",
    "n": 60,
    "hp": 28,
    "ff": 32,
    "share": 46.7,
    "gas_rows": 59,
    "gas_distinctness": 0.78
   },
   {
    "source": "Mansfield, MA",
    "n": 75,
    "hp": 33,
    "ff": 42,
    "share": 44.0,
    "gas_rows": 98,
    "gas_distinctness": 0.89
   },
   {
    "source": "Hingham, MA",
    "n": 35,
    "hp": 15,
    "ff": 20,
    "share": 42.9,
    "gas_rows": 109,
    "gas_distinctness": 0.94
   },
   {
    "source": "Milton, MA",
    "n": 66,
    "hp": 26,
    "ff": 40,
    "share": 39.4,
    "gas_rows": 79,
    "gas_distinctness": 0.95
   },
   {
    "source": "Falmouth, MA",
    "n": 50,
    "hp": 17,
    "ff": 33,
    "share": 34.0,
    "gas_rows": 177,
    "gas_distinctness": 0.81
   },
   {
    "source": "Hanson, MA",
    "n": 30,
    "hp": 10,
    "ff": 20,
    "share": 33.3,
    "gas_rows": 65,
    "gas_distinctness": 0.83
   },
   {
    "source": "Braintree, MA",
    "n": 61,
    "hp": 18,
    "ff": 43,
    "share": 29.5,
    "gas_rows": 20,
    "gas_distinctness": 1.0
   },
   {
    "source": "Taunton, MA",
    "n": 41,
    "hp": 12,
    "ff": 29,
    "share": 29.3,
    "gas_rows": 112,
    "gas_distinctness": 0.76
   },
   {
    "source": "Rockland, MA",
    "n": 51,
    "hp": 12,
    "ff": 39,
    "share": 23.5,
    "gas_rows": 70,
    "gas_distinctness": 0.76
   },
   {
    "source": "West Bridgewater, MA",
    "n": 30,
    "hp": 6,
    "ff": 24,
    "share": 20.0,
    "gas_rows": 41,
    "gas_distinctness": 0.93
   }
  ],
  "excluded": [
   {
    "source": "Worcester, MA",
    "n": 305,
    "hp": 0,
    "ff": 305,
    "share": 0.0,
    "gas_rows": 556,
    "gas_distinctness": 0.01
   },
   {
    "source": "Cambridge, MA",
    "n": 105,
    "hp": 92,
    "ff": 13,
    "share": 87.6,
    "gas_rows": 226,
    "gas_distinctness": 0.06
   },
   {
    "source": "Lexington, MA",
    "n": 52,
    "hp": 52,
    "ff": 0,
    "share": 100.0,
    "gas_rows": 84,
    "gas_distinctness": 0.01
   }
  ]
 }
}