{
  "generated": "Live calculator assumptions; values change when the data layer is updated (see checked dates).",
  "calculator": "https://heatpumpinstallation.ie/calculator/",
  "method": "https://heatpumpinstallation.ie/research/methodology/",
  "rounding": "Money rounded to the nearest €10; floor area to the nearest m²; payback to 0.1 year.",
  "rows": [
    {
      "id": "cost.under-90",
      "label": "Installed cost, Small home, under 90 m²",
      "value": {
        "min": 13000,
        "max": 16000
      },
      "unit": "€ range, incl. VAT",
      "usedFor": "Installed cost before grant, picked by floor area",
      "source": "GetSolarPanels.ie, Air to Water Heat Pump Cost Ireland 2026 (updated 18 Jun 2026) (basic replacement €13,000–€16,000); glasmo.ie guide (updated May 2026) (under 100 m² €13,000–€15,000)",
      "url": "https://www.getsolarpanels.ie/air-to-water-heat-pump-cost-ireland-2026/",
      "checked": "2026-10-10",
      "verified": false
    },
    {
      "id": "cost.90-130",
      "label": "Installed cost, Typical 3-bed semi-d, 90–130 m²",
      "value": {
        "min": 15000,
        "max": 18000
      },
      "unit": "€ range, incl. VAT",
      "usedFor": "Installed cost before grant, picked by floor area",
      "source": "glasmo.ie guide (updated May 2026) (100–150 m² 3-bed semi-d €15,000–€18,000); SEAI median for a semi-d or end of terrace €16,741 (Jan–Jun 2026)",
      "url": "https://glasmo.ie/guide",
      "checked": "2026-10-10",
      "verified": false
    },
    {
      "id": "cost.130-180",
      "label": "Installed cost, 4-bed detached, 130–180 m²",
      "value": {
        "min": 17000,
        "max": 22000
      },
      "unit": "€ range, incl. VAT",
      "usedFor": "Installed cost before grant, picked by floor area",
      "source": "glasmo.ie guide (updated May 2026) (150–200 m² €17,000–€22,000); GetSolarPanels.ie, Air to Water Heat Pump Cost Ireland 2026 (updated 18 Jun 2026) (standard retrofit €16,000–€22,000)",
      "url": "https://glasmo.ie/guide",
      "checked": "2026-10-10",
      "verified": false
    },
    {
      "id": "cost.over-180",
      "label": "Installed cost, Large detached, over 180 m²",
      "value": {
        "min": 20000,
        "max": 28000
      },
      "unit": "€ range, incl. VAT",
      "usedFor": "Installed cost before grant, picked by floor area",
      "source": "glasmo.ie guide (updated May 2026) (over 200 m² €20,000–€28,000); GetSolarPanels.ie, Air to Water Heat Pump Cost Ireland 2026 (updated 18 Jun 2026) (premium retrofit €22,000–€28,000)",
      "url": "https://glasmo.ie/guide",
      "checked": "2026-10-10",
      "verified": false,
      "note": "Complex jobs (several zones, long pipe runs, all new emitters) can cost more"
    },
    {
      "id": "cost.radiatorUpgrade",
      "label": "Radiator upgrades",
      "value": {
        "min": 1500,
        "max": 5000
      },
      "unit": "€ range",
      "usedFor": "Added when the visitor says new radiators are needed (0 to max when not sure)",
      "source": "HomeUpgrade.ie (€1,500–€4,000, radiators or UFH); GetSolarPanels.ie, Air to Water Heat Pump Cost Ireland 2026 (updated 18 Jun 2026) (€1,500–€5,000)",
      "url": "https://www.getsolarpanels.ie/air-to-water-heat-pump-cost-ireland-2026/",
      "checked": "2026-10-10",
      "verified": false,
      "note": "Only where the room-by-room design shows existing radiators are too small"
    },
    {
      "id": "cost.seaiMedians",
      "label": "SEAI median heat pump prices by house type",
      "value": {
        "heatPump": {
          "detached": 17000,
          "semiOrEndTerrace": 16741,
          "midTerrace": 16000,
          "apartment": 9025
        },
        "ber": {
          "detached": 280,
          "semiOrEndTerrace": 280,
          "midTerrace": 275,
          "apartment": 245
        },
        "period": {
          "from": "2026-01-01",
          "to": "2026-06-30"
        },
        "upgradesInSample": 23412
      },
      "unit": "€",
      "usedFor": "Check on the guide ranges (shown, not used in the arithmetic)",
      "source": "SEAI, Better Energy Homes and Solar PV: individual energy upgrades costs and grants (median costs, Jan–Jun 2026)",
      "url": "https://www.seai.ie/sites/default/files/publications/Median-costs-of-individual-energy-upgrades.pdf",
      "checked": "2026-10-14",
      "verified": true,
      "note": "Median of costs submitted by registered contractors at grant payment; 23,412 upgrades of all types"
    },
    {
      "id": "cost.vat",
      "label": "VAT rate on heat pump systems",
      "value": {
        "ratePercent": 9,
        "since": "2025-01-01"
      },
      "unit": "%",
      "usedFor": "Prices include it",
      "source": "Revenue, Heat pump heating systems (published 2 Jan 2025); Revenue current VAT rates (second reduced rate 9%)",
      "url": "https://www.revenue.ie/en/vat/vat-on-property-and-construction/construction-fixtures-fittings-solar-panels/heat-pump-heating-system/index.aspx",
      "checked": "2026-10-10",
      "verified": true
    },
    {
      "id": "grant.house.heatPumpUnit",
      "label": "Grant: heat pump (house)",
      "value": 10500,
      "unit": "€",
      "usedFor": "Every eligible house",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Up to; for installing a heat pump system"
    },
    {
      "id": "grant.house.centralHeatingUpgrade",
      "label": "Grant: central heating upgrade (house)",
      "value": 2000,
      "unit": "€",
      "usedFor": "Only when new radiators or underfloor heating are needed",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Up to; new radiators and/or underfloor heating where the installation design needs them"
    },
    {
      "id": "grant.house.boilerScrappage",
      "label": "Grant: boiler scrappage (house)",
      "value": 2000,
      "unit": "€",
      "usedFor": "Oil, gas, solid fuel, electric storage, or no central heating",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Removing an oil or gas boiler, solid fuel system or electric storage heating; also homes without central heating"
    },
    {
      "id": "grant.apartment.heatPumpUnit",
      "label": "Grant: heat pump (apartment)",
      "value": 8500,
      "unit": "€",
      "usedFor": "Apartments",
      "source": "SEAI, Better Energy Homes Homeowner Application Guide (5 Oct 2026)",
      "url": "https://www.seai.ie/sites/default/files/publications/Homeowner-Application-Guide.pdf",
      "checked": "2026-10-09",
      "verified": true
    },
    {
      "id": "grant.apartment.centralHeatingUpgrade",
      "label": "Grant: central heating upgrade (apartment)",
      "value": 1000,
      "unit": "€",
      "usedFor": "Apartments, when needed",
      "source": "SEAI, Better Energy Homes Homeowner Application Guide (5 Oct 2026)",
      "url": "https://www.seai.ie/sites/default/files/publications/Homeowner-Application-Guide.pdf",
      "checked": "2026-10-09",
      "verified": true
    },
    {
      "id": "grant.apartment.boilerScrappage",
      "label": "Grant: boiler scrappage (apartment)",
      "value": 2000,
      "unit": "€",
      "usedFor": "Apartments, qualifying systems",
      "source": "SEAI, Better Energy Homes Homeowner Application Guide (5 Oct 2026)",
      "url": "https://www.seai.ie/sites/default/files/publications/Homeowner-Application-Guide.pdf",
      "checked": "2026-10-09",
      "verified": true
    },
    {
      "id": "grant.apartmentMax",
      "label": "Grant: apartment maximum",
      "value": 11500,
      "unit": "€",
      "usedFor": "Cap on the apartment total",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "All heat pump types except air to air"
    },
    {
      "id": "grant.eligibility.builtAndOccupiedBefore",
      "label": "Built and occupied before",
      "value": 2021,
      "unit": "year",
      "usedFor": "Homes from this year get no grant",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Home must also have an MPRN"
    },
    {
      "id": "grant.eligibility.technicalAssessmentIfBuiltBefore",
      "label": "Technical assessment if built before",
      "value": 2007,
      "unit": "year",
      "usedFor": "Flags the assessment",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true
    },
    {
      "id": "grant.eligibility.hliThreshold",
      "label": "Heat Loss Indicator threshold",
      "value": 2.3,
      "unit": "W/K·m²",
      "usedFor": "At or below this, no assessment needed",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "W/(K·m²): pre-2007 homes with a valid BER at or below this can self-declare instead"
    },
    {
      "id": "grant.technicalAssessmentFee",
      "label": "Technical assessment grant",
      "value": 200,
      "unit": "€",
      "usedFor": "Shown with the assessment note",
      "source": "SEAI, Heat pump system grant page",
      "url": "https://www.seai.ie/grants/home-energy-grants/individual-grants/heat-pump-systems",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Required for homes built before 2007 unless a valid BER shows HLI ≤ 2.3; done before applying"
    },
    {
      "id": "demand.meteredFuelPerM2",
      "label": "Metered fuel use per m² by BER band",
      "value": {
        "AB": {
          "min": 75,
          "max": 88
        },
        "C": {
          "min": 86,
          "max": 101
        },
        "D": {
          "min": 96,
          "max": 112
        },
        "E": {
          "min": 103,
          "max": 119
        },
        "FG": {
          "min": 104,
          "max": 120
        }
      },
      "unit": "kWh/m²/yr range",
      "usedFor": "Yearly fuel use = this × floor area",
      "source": "CSO, Household Gas Consumption by BER 2022 (Table A; 233,735 dwellings)",
      "url": "https://www.cso.ie/en/releasesandpublications/ep/p-dberngs/householdgasconsumptionbybuildingenergyratings2022/keyfindings/",
      "checked": "2026-10-09",
      "verified": true,
      "note": "kWh of gas delivered per m² per year; includes hot water and a small amount of cooking"
    },
    {
      "id": "demand.floorAreaByPeriodAndType",
      "label": "Average floor area by build period and type",
      "value": {
        "1700-1899": {
          "apartment": 51,
          "detached": 166,
          "semiDetached": 154,
          "endTerrace": 121,
          "midTerrace": 110
        },
        "1900-1929": {
          "apartment": 46,
          "detached": 131,
          "semiDetached": 127,
          "endTerrace": 100,
          "midTerrace": 93
        },
        "1930-1949": {
          "apartment": 57,
          "detached": 127,
          "semiDetached": 117,
          "endTerrace": 87,
          "midTerrace": 84
        },
        "1950-1966": {
          "apartment": 59,
          "detached": 133,
          "semiDetached": 121,
          "endTerrace": 91,
          "midTerrace": 88
        },
        "1967-1977": {
          "apartment": 61,
          "detached": 145,
          "semiDetached": 114,
          "endTerrace": 88,
          "midTerrace": 87
        },
        "1978-1982": {
          "apartment": 64,
          "detached": 149,
          "semiDetached": 101,
          "endTerrace": 86,
          "midTerrace": 84
        },
        "1983-1993": {
          "apartment": 57,
          "detached": 157,
          "semiDetached": 100,
          "endTerrace": 84,
          "midTerrace": 82
        },
        "1994-1999": {
          "apartment": 61,
          "detached": 170,
          "semiDetached": 105,
          "endTerrace": 86,
          "midTerrace": 84
        },
        "2000-2004": {
          "apartment": 69,
          "detached": 186,
          "semiDetached": 107,
          "endTerrace": 98,
          "midTerrace": 93
        },
        "2005-2009": {
          "apartment": 72,
          "detached": 206,
          "semiDetached": 109,
          "endTerrace": 102,
          "midTerrace": 99
        },
        "2010-2014": {
          "apartment": 74,
          "detached": 240,
          "semiDetached": 125,
          "endTerrace": 117,
          "midTerrace": 111
        },
        "2015-2019": {
          "apartment": 81,
          "detached": 214,
          "semiDetached": 125,
          "endTerrace": 119,
          "midTerrace": 113
        },
        "2020-2024": {
          "apartment": 73,
          "detached": 205,
          "semiDetached": 118,
          "endTerrace": 111,
          "midTerrace": 105
        }
      },
      "unit": "m²",
      "usedFor": "Floor area when the visitor doesn't give one (averaged over the periods in the age band)",
      "source": "CSO, Domestic BER Q2 2026, Table 12",
      "url": "https://www.cso.ie/en/releasesandpublications/ep/p-dber/domesticbuildingenergyratingsquarter22026/",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Apartment = ground-floor apartment column"
    },
    {
      "id": "demand.avgBerByPeriodAndType",
      "label": "Average BER energy value by build period and type",
      "value": {
        "1700-1899": {
          "apartment": 443,
          "detached": 372,
          "semiDetached": 344,
          "endTerrace": 376,
          "midTerrace": 334
        },
        "1900-1929": {
          "apartment": 495,
          "detached": 378,
          "semiDetached": 340,
          "endTerrace": 375,
          "midTerrace": 343
        },
        "1930-1949": {
          "apartment": 376,
          "detached": 354,
          "semiDetached": 298,
          "endTerrace": 316,
          "midTerrace": 293
        },
        "1950-1966": {
          "apartment": 432,
          "detached": 312,
          "semiDetached": 268,
          "endTerrace": 297,
          "midTerrace": 272
        },
        "1967-1977": {
          "apartment": 358,
          "detached": 266,
          "semiDetached": 255,
          "endTerrace": 260,
          "midTerrace": 236
        },
        "1978-1982": {
          "apartment": 321,
          "detached": 224,
          "semiDetached": 229,
          "endTerrace": 229,
          "midTerrace": 208
        },
        "1983-1993": {
          "apartment": 351,
          "detached": 205,
          "semiDetached": 216,
          "endTerrace": 223,
          "midTerrace": 205
        },
        "1994-1999": {
          "apartment": 279,
          "detached": 182,
          "semiDetached": 202,
          "endTerrace": 223,
          "midTerrace": 206
        },
        "2000-2004": {
          "apartment": 256,
          "detached": 168,
          "semiDetached": 191,
          "endTerrace": 193,
          "midTerrace": 175
        },
        "2005-2009": {
          "apartment": 179,
          "detached": 136,
          "semiDetached": 162,
          "endTerrace": 161,
          "midTerrace": 147
        },
        "2010-2014": {
          "apartment": 118,
          "detached": 89,
          "semiDetached": 85,
          "endTerrace": 89,
          "midTerrace": 84
        },
        "2015-2019": {
          "apartment": 60,
          "detached": 53,
          "semiDetached": 52,
          "endTerrace": 53,
          "midTerrace": 50
        },
        "2020-2024": {
          "apartment": 46,
          "detached": 38,
          "semiDetached": 40,
          "endTerrace": 39,
          "midTerrace": 37
        }
      },
      "unit": "kWh/m²/yr",
      "usedFor": "BER band when the visitor doesn't know it",
      "source": "CSO, Domestic BER Q4 2024, Table 13",
      "url": "https://www.cso.ie/en/releasesandpublications/ep/p-dber/domesticbuildingenergyratingsquarter42024/",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Apartment = ground-floor apartment column (the \"apartment (not stated)\" column has very small samples)"
    },
    {
      "id": "demand.berScale",
      "label": "BER band upper limits (scale from 24 May 2026)",
      "value": {
        "A0": 42,
        "A": 75,
        "B": 150,
        "C": 225,
        "D": 275,
        "E": 325,
        "F": 375,
        "G": null
      },
      "unit": "kWh/m²/yr",
      "usedFor": "Places an energy value in a band",
      "source": "CSO, Domestic BER Q2 2026, background notes",
      "url": "https://www.cso.ie/en/releasesandpublications/ep/p-dber/domesticbuildingenergyratingsquarter22026/backgroundnotes/",
      "checked": "2026-10-09",
      "verified": true,
      "note": "A0 also needs zero on-site fossil fuel emissions (Zero Emission Building)"
    },
    {
      "id": "fuel.price.oil",
      "label": "Fuel price: oil",
      "value": 11.72,
      "unit": "c/kWh incl. VAT, excl. standing charge",
      "usedFor": "Current running cost = fuel use × price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Kerosene, typical discounted price (1,000 L delivered); schedule price 12.60c"
    },
    {
      "id": "fuel.price.gas",
      "label": "Fuel price: gas",
      "value": 13,
      "unit": "c/kWh incl. VAT, excl. standing charge",
      "usedFor": "Current running cost = fuel use × price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Natural gas Band D2 (5,556–55,556 kWh a year), the typical household band; plus standing charge"
    },
    {
      "id": "fuel.price.lpg",
      "label": "Fuel price: lpg",
      "value": 17.67,
      "unit": "c/kWh incl. VAT, excl. standing charge",
      "usedFor": "Current running cost = fuel use × price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Bulk LPG; plus standing charge"
    },
    {
      "id": "fuel.price.solid",
      "label": "Fuel price: solid",
      "value": 9.45,
      "unit": "c/kWh incl. VAT, excl. standing charge",
      "usedFor": "Current running cost = fuel use × price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Low-smoke coal ovoids, 40 kg bag; briquettes 16.71c, bagged hardwood 15.80c"
    },
    {
      "id": "fuel.price.electric-storage",
      "label": "Fuel price: electric-storage",
      "value": 15.42,
      "unit": "c/kWh incl. VAT, excl. standing charge",
      "usedFor": "Current running cost = fuel use × price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Night-rate electricity (needs a second meter)"
    },
    {
      "id": "fuel.price.electric-direct",
      "label": "Fuel price: electric-direct",
      "value": 34.38,
      "unit": "c/kWh incl. VAT, excl. standing charge",
      "usedFor": "Current running cost = fuel use × price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Electricity Band DD (5,000–15,000 kWh a year)"
    },
    {
      "id": "fuel.price.electricityStandard",
      "label": "Electricity, standard rate (Band DD)",
      "value": 34.38,
      "unit": "c/kWh",
      "usedFor": "Heat pump running cost",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Band DD (5,000–15,000 kWh a year), excludes standing charge"
    },
    {
      "id": "fuel.efficiency.oil",
      "label": "Seasonal efficiency: oil",
      "value": {
        "min": 0.6,
        "max": 0.75
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Oil-fired boiler (kerosene) 60–75%"
    },
    {
      "id": "fuel.efficiency.oilCondensing",
      "label": "Seasonal efficiency: oilCondensing",
      "value": {
        "min": 0.85,
        "max": 0.97
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Condensing boiler 85–97%"
    },
    {
      "id": "fuel.efficiency.gas",
      "label": "Seasonal efficiency: gas",
      "value": {
        "min": 0.55,
        "max": 0.75
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Gas-fired boiler (non-condensing) 55–75%"
    },
    {
      "id": "fuel.efficiency.gasCondensing",
      "label": "Seasonal efficiency: gasCondensing",
      "value": {
        "min": 0.85,
        "max": 0.97
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Condensing boiler 85–97%"
    },
    {
      "id": "fuel.efficiency.lpg",
      "label": "Seasonal efficiency: lpg",
      "value": {
        "min": 0.55,
        "max": 0.75
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Gas-fired boiler band 55–75% (SEAI gives no separate LPG band; condensing LPG boilers fall in the 85–97% condensing band)"
    },
    {
      "id": "fuel.efficiency.solid",
      "label": "Seasonal efficiency: solid",
      "value": {
        "min": 0.65,
        "max": 0.85
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Stove / closed room heater with back boiler 65–85%; open fire with high-output back boiler 40–50%"
    },
    {
      "id": "fuel.efficiency.electric-storage",
      "label": "Seasonal efficiency: electric-storage",
      "value": {
        "min": 0.9,
        "max": 0.9
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Electric storage heater 90%"
    },
    {
      "id": "fuel.efficiency.electric-direct",
      "label": "Seasonal efficiency: electric-direct",
      "value": {
        "min": 1,
        "max": 1
      },
      "unit": "fraction (range)",
      "usedFor": "Useful heat = fuel use × efficiency (condensing assumed for homes built from 2007)",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "Electric fire / panel heater 100%"
    },
    {
      "id": "fuel.spf.airToWater",
      "label": "Heat pump SPF band (air to water)",
      "value": {
        "min": 2.5,
        "max": 4
      },
      "unit": "ratio (range)",
      "usedFor": "Heat pump cost range = useful heat ÷ SPF × electricity price",
      "source": "SEAI Domestic Fuel Cost Comparison, 1 July 2026",
      "url": "https://www.seai.ie/sites/default/files/publications/Domestic-Fuel-Cost-Comparison.pdf",
      "checked": "2026-10-09",
      "verified": true,
      "note": "SEAI assumes low-temperature emitters such as underfloor heating"
    },
    {
      "id": "fuel.spfMeasured",
      "label": "Measured Irish heat pump SPF (FactHP)",
      "value": {
        "mean": 3.22,
        "median": 3.1,
        "q1": 2.94,
        "q3": 3.46,
        "systems": 36,
        "meanElectricityKwh": 4982
      },
      "unit": "ratio",
      "usedFor": "Single \"typical\" heat pump cost uses the mean",
      "source": "SEAI-funded FactHP field trial, Final Data Analysis Report (LIT, 15 Dec 2020), Table 2",
      "url": "https://www.seai.ie/sites/default/files/documents/research-project/RDD-000216.pdf",
      "checked": "2026-10-10",
      "verified": true,
      "note": "Mostly deep retrofits by engaged owners; a typical retrofit can do worse"
    }
  ]
}