{
 "slug": "heat-pump-share",
 "computed_from": "masspermits.com build",
 "corpus_fetched_at": "2026-09-06T07:42:47.738505+00:00",
 "corpus_rows": 37571,
 "corpus_sources": 31,
 "corpus_first": "2026-03-10",
 "corpus_last": "2026-09-06",
 "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": 550,
  "eligible_hp": 171,
  "pooled_share": 31.1,
  "min_share": 13.8,
  "max_share": 44.2,
  "spread": 3.2,
  "excluded_towns": 3,
  "thin_towns": 18,
  "n_sources": 31,
  "excluded_rows": 449,
  "excluded_vs_eligible": "nearly as many as",
  "top": {
   "source": "Mansfield, MA",
   "n": 77,
   "hp": 34,
   "ff": 43,
   "share": 44.2,
   "gas_rows": 98,
   "gas_distinctness": 0.92
  },
  "bottom": {
   "source": "West Bridgewater, MA",
   "n": 29,
   "hp": 4,
   "ff": 25,
   "share": 13.8,
   "gas_rows": 43,
   "gas_distinctness": 0.91
  },
  "table": [
   {
    "source": "Mansfield, MA",
    "n": 77,
    "hp": 34,
    "ff": 43,
    "share": 44.2,
    "gas_rows": 98,
    "gas_distinctness": 0.92
   },
   {
    "source": "Randolph, MA",
    "n": 72,
    "hp": 30,
    "ff": 42,
    "share": 41.7,
    "gas_rows": 56,
    "gas_distinctness": 0.79
   },
   {
    "source": "Hingham, MA",
    "n": 38,
    "hp": 15,
    "ff": 23,
    "share": 39.5,
    "gas_rows": 105,
    "gas_distinctness": 0.92
   },
   {
    "source": "Milton, MA",
    "n": 59,
    "hp": 22,
    "ff": 37,
    "share": 37.3,
    "gas_rows": 80,
    "gas_distinctness": 0.95
   },
   {
    "source": "Hanson, MA",
    "n": 34,
    "hp": 11,
    "ff": 23,
    "share": 32.4,
    "gas_rows": 64,
    "gas_distinctness": 0.86
   },
   {
    "source": "Rockland, MA",
    "n": 55,
    "hp": 16,
    "ff": 39,
    "share": 29.1,
    "gas_rows": 68,
    "gas_distinctness": 0.74
   },
   {
    "source": "Braintree, MA",
    "n": 96,
    "hp": 21,
    "ff": 75,
    "share": 21.9,
    "gas_rows": 19,
    "gas_distinctness": 1.0
   },
   {
    "source": "Falmouth, MA",
    "n": 47,
    "hp": 10,
    "ff": 37,
    "share": 21.3,
    "gas_rows": 185,
    "gas_distinctness": 0.74
   },
   {
    "source": "Taunton, MA",
    "n": 43,
    "hp": 8,
    "ff": 35,
    "share": 18.6,
    "gas_rows": 127,
    "gas_distinctness": 0.72
   },
   {
    "source": "West Bridgewater, MA",
    "n": 29,
    "hp": 4,
    "ff": 25,
    "share": 13.8,
    "gas_rows": 43,
    "gas_distinctness": 0.91
   }
  ],
  "excluded": [
   {
    "source": "Worcester, MA",
    "n": 299,
    "hp": 0,
    "ff": 299,
    "share": 0.0,
    "gas_rows": 576,
    "gas_distinctness": 0.01
   },
   {
    "source": "Cambridge, MA",
    "n": 97,
    "hp": 83,
    "ff": 14,
    "share": 85.6,
    "gas_rows": 214,
    "gas_distinctness": 0.05
   },
   {
    "source": "Lexington, MA",
    "n": 53,
    "hp": 50,
    "ff": 3,
    "share": 94.3,
    "gas_rows": 95,
    "gas_distinctness": 0.01
   }
  ]
 }
}