{
  "thermostat_id": "thermostat-a1b2c3",
  "period_start": "2026-04-01T00:00:00Z",
  "period_end": "2026-04-30T23:59:59Z",
  "heating_runtime_minutes": 120,
  "cooling_runtime_minutes": 480,
  "fan_runtime_minutes": 60,
  "estimated_kwh": 45.2,
  "average_indoor_temp": 71.5,
  "average_outdoor_temp": 82.3
}