CFM from BTU load & air changes API

Computes the required airflow CFM = BTU/h / (1.08·ΔT) to deliver a sensible HVAC load (also in L/s and m³/h) and the air changes per hour ACH = CFM·60/volume for a room. Answers 'What CFM do I need for this cooling load?', 'How many air changes per hour does this airflow give?'.

Price$0.04per request

MethodPOST

Route/v1/engineering/airflow-cfm

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

engineeringthermofluidshvaccfmbtuair-changesachairflowventilationcooling-load

API URLhttps://x402.hexl.dev/v1/engineering/airflow-cfm

Integration docs

Example request

{
  "sensibleLoadBtuH": 24000,
  "supplyTempDiffF": 20,
  "roomVolumeFt3": 2000
}

Example response

{
  "sensibleLoadBtuH": 24000,
  "supplyTempDiffF": 20,
  "formula": "CFM = BTU/h / (1.08*ΔT_F); ACH = CFM*60/Volume_ft3",
  "cfm": 1111.1111,
  "airflowLs": 524.385556,
  "airflowM3h": 1887.788889,
  "roomVolumeFt3": 2000,
  "airChangesPerHour": 33.3333
}

Input schema

{
  "type": "object",
  "required": [],
  "properties": {
    "sensibleLoadBtuH": {
      "type": "number",
      "description": "sensible heating/cooling load (BTU/h)",
      "examples": [
        24000
      ]
    },
    "supplyTempDiffF": {
      "type": "number",
      "description": "supply-to-room temperature difference (°F)",
      "examples": [
        20
      ]
    },
    "cfm": {
      "type": "number",
      "description": "airflow (CFM); alternative to load+ΔT"
    },
    "roomVolumeFt3": {
      "type": "number",
      "description": "room volume (ft^3) for ACH"
    },
    "roomVolumeM3": {
      "type": "number",
      "description": "room volume (m^3) for ACH"
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}