{
  "version": "2026-08-29.1",
  "checked_date": "2026-08-29",
  "geography": "Great Britain average price-cap rates",
  "presets": {
    "2026-q3": {
      "label": "Ofgem average, 1 July to 30 September 2026",
      "electricity_unit_p": 26.11,
      "electricity_standing_p_day": 57.19,
      "gas_unit_p": 7.33,
      "gas_standing_p_day": 29.04,
      "source": "ofgem-rates"
    },
    "2026-q4": {
      "label": "Ofgem announced average, 1 October to 31 December 2026",
      "electricity_unit_p": 26.32,
      "electricity_standing_p_day": 54.83,
      "gas_unit_p": 7.97,
      "gas_standing_p_day": 29.68,
      "source": "ofgem-rates"
    }
  },
  "systems": [
    {
      "id": "gas",
      "name": "Gas boiler",
      "performance": 0.9,
      "performance_label": "Seasonal efficiency"
    },
    {
      "id": "direct-electric",
      "name": "Direct electric heating",
      "performance": 1.0,
      "performance_label": "Efficiency"
    },
    {
      "id": "heat-pump",
      "name": "Heat pump",
      "performance": 3.0,
      "performance_label": "Seasonal COP"
    }
  ],
  "sources": {
    "ofgem-rates": {
      "title": "Energy price cap unit rates and standing charges",
      "publisher": "Ofgem",
      "url": "https://www.ofgem.gov.uk/information-consumers/energy-advice-households/energy-price-cap-unit-rates-and-standing-charges",
      "scope": "Average Direct Debit electricity and gas unit rates and standing charges for England, Scotland and Wales. Actual tariffs vary by region, payment method and contract."
    },
    "ofgem-q3": {
      "title": "Changes to energy price cap between 1 July and 30 September 2026",
      "publisher": "Ofgem",
      "url": "https://www.ofgem.gov.uk/news/changes-energy-price-cap-between-1-july-and-30-september-2026",
      "scope": "Published confirmation of Q3 2026 average Direct Debit rates and the limits of the price-cap illustration."
    }
  },
  "formula": {
    "input_energy_kwh": "delivered_heat_kwh / performance",
    "energy_cost_gbp": "input_energy_kwh * unit_rate_p_per_kwh / 100",
    "standing_cost_gbp": "standing_charge_p_per_day * 365 / 100 when explicitly included"
  },
  "worked_example": [
    {
      "system": "Gas boiler",
      "performance_assumption": 0.9,
      "unit_rate_p_per_kwh": 7.33,
      "standing_charge_p_per_day": 29.04,
      "delivered_heat_kwh": 12000,
      "input_energy_kwh": 13333.333,
      "energy_only_cost_gbp": 977.33,
      "cost_with_full_standing_charge_gbp": 1083.33
    },
    {
      "system": "Direct electric heating",
      "performance_assumption": 1.0,
      "unit_rate_p_per_kwh": 26.11,
      "standing_charge_p_per_day": 57.19,
      "delivered_heat_kwh": 12000,
      "input_energy_kwh": 12000.0,
      "energy_only_cost_gbp": 3133.2,
      "cost_with_full_standing_charge_gbp": 3341.94
    },
    {
      "system": "Heat pump",
      "performance_assumption": 3.0,
      "unit_rate_p_per_kwh": 26.11,
      "standing_charge_p_per_day": 57.19,
      "delivered_heat_kwh": 12000,
      "input_energy_kwh": 4000.0,
      "energy_only_cost_gbp": 1044.4,
      "cost_with_full_standing_charge_gbp": 1253.14
    }
  ]
}