{
  "provider": {
    "name": "CalculateEnergySavings.com",
    "source_url": "https://calculateenergysavings.com/",
    "terms_url": "https://calculateenergysavings.com/api-terms/",
    "terms_version": "2026-08-25"
  },
  "id": "process-heating-exhaust-loss",
  "name": "Process-Heating Exhaust & Heat Loss Screening Calculator",
  "description": "Estimate exhaust sensible heat and shell-loss reductions from measured conditions, with explicit fuel-displacement assumptions.",
  "status": "published",
  "callable": true,
  "version": "1.0.0",
  "url": "https://calculateenergysavings.com/calculators/process-heating-exhaust-loss/",
  "methodology_url": "https://calculateenergysavings.com/calculators/process-heating-exhaust-loss/#methodology",
  "api_url": "https://calculateenergysavings.com/api/v1/calculators/process-heating-exhaust-loss",
  "calculate_url": "https://calculateenergysavings.com/api/v1/calculators/process-heating-exhaust-loss/calculate",
  "input_schema": {
    "type": "object",
    "additionalProperties": false,
    "properties": {
      "installedCost": {
        "type": "number"
      },
      "incentiveAmount": {
        "type": "number",
        "default": 0
      },
      "annualMaintenanceSavings": {
        "type": "number",
        "default": 0
      },
      "projectLife": {
        "type": "number",
        "default": 10
      },
      "discountRatePercent": {
        "type": "number",
        "default": 7
      },
      "energyEscalationPercent": {
        "type": "number",
        "default": 0
      },
      "exhaustMassLbHour": {
        "type": "number",
        "default": 1000,
        "title": "Exhaust mass flow",
        "x-unit": "lb/hour",
        "description": "Use measured/engineered mass flow, not actual or standard cfm.",
        "minimum": 0.01
      },
      "heatCapacity": {
        "type": "number",
        "default": 0.25,
        "title": "Mean exhaust specific heat",
        "x-unit": "Btu/lb·°F",
        "description": "Example 0.25 only; obtain a gas-composition and temperature-appropriate value.",
        "minimum": 0.01,
        "maximum": 2
      },
      "referenceTemperatureF": {
        "type": "number",
        "default": 70,
        "title": "Reference temperature",
        "x-unit": "°F",
        "minimum": -50,
        "maximum": 200
      },
      "existingExhaustTemperatureF": {
        "type": "number",
        "default": 500,
        "title": "Existing exhaust temperature",
        "x-unit": "°F",
        "minimum": 0,
        "maximum": 3000
      },
      "proposedExhaustTemperatureF": {
        "type": "number",
        "default": 350,
        "title": "Proposed exhaust temperature",
        "x-unit": "°F",
        "minimum": 0,
        "maximum": 3000
      },
      "existingOtherLoss": {
        "type": "number",
        "default": 20000,
        "title": "Existing other heat loss",
        "x-unit": "Btu/hour",
        "description": "Independent shell/opening estimate; exclude exhaust already counted above.",
        "minimum": 0
      },
      "proposedOtherLoss": {
        "type": "number",
        "default": 10000,
        "title": "Proposed other heat loss",
        "x-unit": "Btu/hour",
        "minimum": 0
      },
      "hours": {
        "type": "number",
        "default": 4000,
        "title": "Annual operating hours",
        "x-unit": "hrs/year",
        "minimum": 1,
        "maximum": 8760
      },
      "marginalEfficiencyPercent": {
        "type": "number",
        "default": 80,
        "title": "Marginal fuel-to-useful-heat efficiency",
        "x-unit": "%",
        "description": "For estimating fuel displaced by recovered heat. Not the same as combustion efficiency; verify with an engineer.",
        "minimum": 1,
        "maximum": 100
      },
      "fuelCostPerMmbtu": {
        "type": "number",
        "default": 12,
        "title": "Marginal purchased fuel price",
        "x-unit": "$/MMBtu",
        "minimum": 0.001
      }
    }
  },
  "example_inputs": {
    "installedCost": "",
    "incentiveAmount": 0,
    "annualMaintenanceSavings": 0,
    "projectLife": 10,
    "discountRatePercent": 7,
    "energyEscalationPercent": 0,
    "exhaustMassLbHour": 1000,
    "heatCapacity": 0.25,
    "referenceTemperatureF": 70,
    "existingExhaustTemperatureF": 500,
    "proposedExhaustTemperatureF": 350,
    "existingOtherLoss": 20000,
    "proposedOtherLoss": 10000,
    "hours": 4000,
    "marginalEfficiencyPercent": 80,
    "fuelCostPerMmbtu": 12
  },
  "source_url": "https://www.energy.gov/sites/default/files/2014/05/f15/process_heating_sourcebook2.pdf",
  "formulas": [
    "Exhaust sensible loss = mass flow × mean specific heat × (exhaust − reference temperature). Add separately estimated shell/opening losses.",
    "Annual avoided heat = (existing loss − proposed loss) × hours ÷ 1,000,000. Indicative displaced fuel = avoided heat ÷ marginal efficiency. Assumes unchanged mass flow, production and operating hours, with all avoided heat usefully replacing fuel; excludes latent heat, chemistry, auxiliary electricity and heat-recovery costs. Verify corrosion/dew point, draft, emissions and safety limits; use a full furnace heat balance for design."
  ],
  "disclaimer": "Screening estimate only. Verify measurements, assumptions, tariffs, equipment constraints, and applicable requirements before making a project or purchasing decision."
}