API · /ventilation-api

Ventilation & Airflow API

healthy 3,404 Subscribers

Ventilation and airflow maths as an API, computed locally and deterministically. The air-changes endpoint relates the air changes per hour, the airflow in CFM and the room volume — ACH = CFM × 60 ÷ volume — and solves whichever you leave out (the volume can be given directly or as length × width × height), reporting the airflow in cubic metres per hour too. The required-cfm endpoint applies the ASHRAE 62.1 breathing-zone rule, outdoor airflow = people × Rp + floor area × Ra, with sensible office defaults (5 CFM per person and 0.06 CFM per square foot), to size the fresh-air a space needs. The duct-velocity endpoint computes the air velocity in a round or rectangular duct from the flow and the duct size, V = CFM ÷ area, in feet per minute, metres per second and miles per hour, with guidance on whether it is in the quiet residential or noisier high-velocity range. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC, building-services, indoor-air-quality and facilities app developers, ventilation-sizing and duct-design tools, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is ventilation and airflow; for heating and cooling load sizing use an HVAC API.

#ventilation #airflow #hvac #air-changes #duct #developer-tools

api.oanor.com/ventilation-api

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Machine-readable spec so AI agents can integrate this API.

/api/ventilation-api/openapi.json

/api/ventilation-api/llms.txt

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Ventilation & Airflow API — live data on the oanor API marketplace

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 75 ms; Server probes · 24h
Subscribers: 3,404; active
Total calls: 76; last 7 days

Full status page → · 12 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

2,000 calls / month
2 requests / second
Hard cap (429 above quota, no overage)
Air changes per hour (ACH) ↔ CFM conversion
Room volume from dimensions
Deterministic, instant results
2,000 calls/month

Starter

€9.00 /month

30,000 calls / month
5 requests / second
Hard cap (429 above quota, no overage)
Full ACH / CFM / duct-velocity endpoints
Required airflow for target ACH
Metric and imperial units
30,000 calls/month

Pro

€24.00 /month

150,000 calls / month
15 requests / second
Hard cap (429 above quota, no overage)
Duct sizing and friction-loss maths
Batch room and zone calculations
Higher 15 rps throughput
150,000 calls/month

Mega

€69.00 /month

750,000 calls / month
40 requests / second
Hard cap (429 above quota, no overage)
Highest volume for HVAC platforms
All ventilation and airflow endpoints
Priority 40 rps throughput
750,000 calls/month

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PremiumApi

Related APIs

Other APIs with overlapping tags.

HVAC Ductwork API

HVAC duct-sizing maths as an API, computed locally and deterministically — the duct dimensions an installer or designer sizes a system with so the air moves quietly and efficiently. The round-duct endpoint gives the round duct for an airflow at a target velocity: area = airflow ÷ velocity (CFM ÷ ft/min = ft²), then diameter = √(4·area/π) — 400 CFM at a 700 fpm trunk velocity wants about a 10.2-inch round, rounded up to the next 12-inch trade size. The velocity endpoint gives the air speed inside a duct from the airflow and its size, round or rectangular — 400 CFM through a 12 × 8 duct runs at 600 fpm, comfortably quiet, while the same air in a 10-inch round moves at 733 fpm. The equivalent endpoint gives the equivalent round diameter of a rectangular duct by the ASHRAE relation De = 1.30 · (a·b)^0.625 ÷ (a+b)^0.25, so a 12 × 8 rectangular carries the same air at the same friction as a 10.7-inch round — letting you size on a round friction chart and convert to fit the space. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC-design and installer apps, duct-sizing and takeoff tools, building-services calculators, and trade-school aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. For room air changes use a ventilation API; for the cooling/heating load use an HVAC API.

api.oanor.com/ductwork-api

HVAC Air-Side Load API

HVAC air-side heat maths as an API, computed locally and deterministically with the classic standard-air factors — the sensible, latent and airflow numbers a mechanical engineer or HVAC technician sizes ducts and equipment with. The sensible endpoint gives the sensible heat an airflow carries to change temperature: Qs = 1.08 × CFM × ΔT (dry-bulb difference), where the 1.08 bundles standard-air density and specific heat — 2,000 CFM across a 20 °F difference is 43,200 BTU/hr, 3.6 tons — with the result in BTU/hr, tons and kW. The latent endpoint gives the latent (moisture) heat: Ql = 0.68 × CFM × ΔW, where ΔW is the humidity-ratio difference in grains of water per pound of dry air, the dehumidification part of a cooling load that runs high in humid climates and from people and cooking, and why air conditioners are sized on total, not just temperature. The airflow endpoint inverts the sensible relation: CFM = sensible load ÷ (1.08 × ΔT), the supply air needed at a chosen supply-to-room temperature difference (comfort cooling runs ~18–22 °F below room), the number that sets fan and duct size — sanity-checked against ~400 CFM per ton. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC-design and load-calc tools, mechanical-estimating and commissioning utilities, and building-engineering apps. Pure local computation — no key, no third-party service, instant. Standard-air factors — adjust for altitude. 3 compute endpoints. For room rule-of-thumb sizing use an HVAC API; for moist-air properties a psychrometric API; for duct sizing a ductwork API.

api.oanor.com/hvacload-api

Electric Motor FLA API

Electric-motor electrical maths as an API, computed locally and deterministically — the full-load-current, NEC-sizing and starting-current numbers an electrician, panel designer or estimator runs for every motor circuit. The full-load-amps endpoint gives the motor current from its power, voltage and phase: FLA = (output ÷ efficiency) ÷ (√3 × volts × power factor) for three-phase (drop the √3 for single-phase) — a 10 hp, 460 V, three-phase motor at 90 % efficiency and 0.85 power factor draws about 12.2 A — and it also returns the input kW and kVA. The sizing endpoint applies NEC Article 430 from the full-load current: branch-circuit conductors at 125 %, overload protection at 115–125 % by service factor, and branch-circuit short-circuit/ground-fault protection up to 250 % for an inverse-time breaker or 175 % for a time-delay fuse — the larger protection lets the inrush pass while the overload guards the windings. The starting endpoint gives the locked-rotor (inrush) current, about six times full-load for an across-the-line start, the figure that sets the voltage dip and why soft starters and VFDs exist. Everything is computed locally and deterministically, so it is instant and private. Ideal for electrical-design and estimating tools, panel-builder and field utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Calculated values — use the NEC FLC tables for code work. 3 compute endpoints. For general three-phase power use a three-phase API; for conduit fill a conduit API.

api.oanor.com/motorfla-api

Heat Pump COP API

Heat-pump and refrigeration performance maths as an API, computed locally and deterministically — the efficiency numbers an HVAC engineer, energy auditor or heat-pump installer actually works with. The cop endpoint gives the coefficient of performance and the US EER rating from the thermal capacity and the electrical power: a unit moving 7 kW of heat on 2 kW of electricity has a COP of 3.5 (an EER of 12), meaning 3.5 units of heating or cooling for every unit of electricity — which is why a heat pump beats resistance heating, where the COP is exactly 1. The carnot endpoint gives the unbeatable ideal limit set only by the absolute temperatures — heating = Th ÷ (Th − Tc), cooling = Tc ÷ (Th − Tc) in kelvin, where heating COP always equals cooling COP plus one — and, given a real COP, the second-law efficiency that says how close the machine runs to that ceiling; the smaller the temperature lift, the higher the limit, which is why ground-source and low-temperature systems beat air-source on a cold day. The capacity endpoint turns electrical power and a COP into the delivered heating or cooling in kilowatts, BTU per hour and tons of refrigeration — the extra energy over the electricity is pulled from the outside air, ground or water. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC and refrigeration engineers, energy auditors, heat-pump and building-performance tools, and sustainability dashboards. Pure local computation — no key, no third-party service, instant. Estimates at the stated conditions — real COP falls as the temperature lift rises. 3 compute endpoints. For room sizing use an HVAC BTU API; for moist-air properties use a psychrometric API.

api.oanor.com/heatpump-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Ventilation & Airflow API?

Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Ventilation & Airflow API with the x-oanor-key header. No credit card needed for the free tier.

What's the rate limit for Ventilation & Airflow API?

Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.

How much does Ventilation & Airflow API cost?

Ventilation & Airflow API has a free tier with 100 calls / month. Paid plans start at €9.00 / month with higher quotas and faster rate limits.

Can I cancel my subscription anytime?

Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.

Is Ventilation & Airflow API GDPR-compliant?

All requests to Ventilation & Airflow API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Ventilation 3

Meta 1

Pick an endpoint from the list on the left to see its details and try it.

GET /v1/air-changes

Air changes per hour

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Parameters

Custom headers

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GET /v1/duct-velocity

Duct velocity

Playground

Parameters

Custom headers

Language: Client:

GET /v1/required-cfm

ASHRAE required CFM

Playground

Parameters

Custom headers

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GET /v1/meta

Spec

Playground

Custom headers

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Code snippets

curl https://api.oanor.com/ventilation-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."

const res = await fetch("https://api.oanor.com/ventilation-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();

$ch = curl_init("https://api.oanor.com/ventilation-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);

import requests
r = requests.get(
    "https://api.oanor.com/ventilation-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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Ventilation & Airflow API

API health

Pricing

Built by

Related APIs

HVAC Ductwork API

HVAC Air-Side Load API

Electric Motor FLA API

Heat Pump COP API

Frequently asked questions

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