#hvac

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 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 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

Steam-boiler engineering maths as an API, computed locally and deterministically — the three numbers a boiler operator, plant engineer or steam-system designer actually works with. The boiler-hp endpoint converts a required heat output into boiler horsepower (heat ÷ 33,475 BTU/hr, the standard definition), the equivalent steam output in pounds per hour "from and at" 212 °F (34.5 lb/hr per BHP) and the output in kilowatts — a 1,000,000 BTU/hr load is about 29.9 BHP or 1,031 lb/hr of steam. The factor-of-evaporation endpoint gives the real capacity for your feedwater: the factor = (the total heat of the steam − the feedwater heat) ÷ 970.3, always greater than one because the boiler must add the sensible heat to bring water up to boiling, so a boiler rated "from and at" 212 °F actually makes less with 60 °F feedwater — which is exactly why preheating feedwater with an economiser raises capacity and saves fuel. The blowdown endpoint gives the continuous blowdown rate to hold the boiler water within its dissolved-solids limit: blowdown = steam × feedwater TDS ÷ (boiler limit − feedwater TDS), with the cycles of concentration and the blowdown as a percentage of feedwater — better feedwater means more cycles, less blowdown and less wasted hot water. Everything is computed locally and deterministically, so it is instant and private. Ideal for boiler operators, steam-plant and HVAC engineers, energy auditors, water-treatment specialists and process-engineering tools. Pure local computation — no key, no third-party service, instant. Engineering estimates — verify against the manufacturer data and local code. 3 compute endpoints. For moist-air properties use a psychrometric API; for compressed air use a compressor API.

api.oanor.com/boiler-api

Pipe-insulation heat-loss maths as an API, computed locally and deterministically — the radial heat loss, thickness and energy-cost numbers a mechanical engineer or energy auditor sizes lagging with. The heat-loss endpoint gives the loss per linear foot through cylindrical insulation, Q/L = 2π·(k/12)·ΔT ÷ ln(r2/r1), where k is the insulation conductivity (BTU·in/hr·ft²·°F, ~0.25 for fibreglass), r1 the pipe radius and r2 the outer radius — a 2-inch line at 300 °F with one inch of fibreglass loses about 43 BTU/hr per foot, and because the relationship is logarithmic, doubling the thickness does not halve the loss. The thickness endpoint inverts it for a target loss: ln(r2/r1) = 2π·(k/12)·ΔT ÷ target, then thickness = r2 − r1, showing the economic-thickness point beyond which more material rarely pays. The annual-cost endpoint turns loss per foot into the yearly heat lost and fuel cost over a run of pipe, the number that justifies the lagging. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical-design and energy-audit apps, insulation-contractor and process-piping tools, building-services calculators, and engineering aids. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 compute endpoints. Ignores the outer air film (real loss slightly lower). For flat walls and roofs use a U-value API.

api.oanor.com/pipeinsulation-api

Radiant-Floor- und Hydronic-Heizungsmathematik als API, lokal und deterministisch berechnet – die Output-, Rohr- und Durchflusszahlen, mit denen ein Installateur oder Heimwerker einen warmen Fußboden plant. Der Output-Endpunkt gibt die Wärme aus, die ein warmer Fußboden abgibt: etwa 2 BTU/h pro Quadratfuß für jedes °F, das die Bodenoberfläche wärmer als der Raum ist, also liefert ein 85 °F-Boden in einem 70 °F-Raum etwa 30 BTU/h/ft² – etwa 9.000 BTU/h über 300 ft², die Komfortgrenze, da der Boden bei ~85 °F gehalten wird. Der Rohr-Endpunkt gibt das Rohr und die Schleifen für eine Fläche bei einem Abstand an: Feldrohr = Fläche × 12 ÷ Abstand, also benötigt 300 ft² bei 9-Zoll-Abstand 400 Fuß Rohr, aufgeteilt in Schleifen unter ~300 Fuß (zwei 200-Fuß-Schleifen), damit die Pumpe sie durchdrücken kann. Der Durchfluss-Endpunkt gibt die Schleifendurchflussrate für eine Heizlast an, GPM = Last ÷ (500 × ΔT), wobei 500 die Wasserkonstante und ΔT die Vorlauf-Rücklauf-Differenz ist – 9.000 BTU/h bei einer ΔT von 20 °F benötigt 0,9 GPM. Alles wird lokal und deterministisch berechnet, daher ist es sofort und privat. Ideal für Fußbodenheizungs- und Sanitäranwendungen, Hydronic-Design- und PEX-Layout-Tools, HVAC-Rechner für Auftragnehmer und DIY-Bau-Seiten. Reine lokale Berechnung – kein Key, kein Drittanbieter-Service, sofort. Live, nichts gespeichert. 3 Compute-Endpunkte. Schätzungen – mit einer vollständigen Wärmeverlustberechnung überprüfen. Für die Gebäudelast eine HVAC-API verwenden; für die Rohrgeschwindigkeit eine Durchflussraten-API.

api.oanor.com/radiant-api

HVAC-Kanaldimensionierungsmathematik als API, lokal und deterministisch berechnet – die Kanalabmessungen, mit denen ein Installateur oder Planer ein System dimensioniert, damit die Luft leise und effizient strömt. Der Rundkanal-Endpunkt gibt den runden Kanal für einen Luftstrom bei einer Zielgeschwindigkeit aus: Fläche = Luftstrom ÷ Geschwindigkeit (CFM ÷ ft/min = ft²), dann Durchmesser = √(4·Fläche/π) – 400 CFM bei einer Hauptgeschwindigkeit von 700 ft/min benötigt etwa einen 10,2-Zoll-Rundkanal, aufgerundet auf die nächste handelsübliche Größe von 12 Zoll. Der Geschwindigkeits-Endpunkt gibt die Luftgeschwindigkeit in einem Kanal aus Luftstrom und Größe an, rund oder rechteckig – 400 CFM durch einen 12 × 8 Kanal laufen mit 600 ft/min, angenehm leise, während die gleiche Luft in einem 10-Zoll-Rundkanal mit 733 ft/min strömt. Der Äquivalenz-Endpunkt gibt den äquivalenten runden Durchmesser eines rechteckigen Kanals nach der ASHRAE-Beziehung De = 1,30 · (a·b)^0,625 ÷ (a+b)^0,25 an, sodass ein 12 × 8 rechteckiger Kanal die gleiche Luft mit dem gleichen Reibungsverlust wie ein 10,7-Zoll-Rundkanal führt – so können Sie mit einer runden Reibungstabelle dimensionieren und an den verfügbaren Platz anpassen. Alles wird lokal und deterministisch berechnet, daher ist es sofort und privat. Ideal für HVAC-Design- und Installateur-Apps, Kanaldimensionierungs- und Auslegungswerkzeuge, Gebäudetechnik-Rechner und Berufsschulhilfen. Reine lokale Berechnung – kein Key, kein Drittanbieter-Service, sofort. Live, nichts wird gespeichert. 3 Compute-Endpunkte. Für Raumluftwechsel verwenden Sie eine Lüftungs-API; für die Kühl-/Heizlast verwenden Sie eine HVAC-API.

api.oanor.com/ductwork-api

Propane and LPG tank maths as an API, computed locally and deterministically — the usable-fill, energy and burn-time numbers a homeowner, RV-er, grill-master or HVAC tech works out at the tank. The tank endpoint turns a tank size into real numbers: liquid propane is 4.24 lb per gallon and holds 91,452 BTU per gallon (about 21,569 BTU per pound), so a 20 lb barbecue cylinder carries roughly 4.7 gallons and 431,000 BTU. It knows the two ways tanks are sized — a portable cylinder (20, 30, 40 lb) is rated by the propane weight it holds, while a bulk tank (100, 250, 500, 1000 gal) is filled to only 80 % of its water capacity to leave room for expansion, so a 500-gallon tank actually holds 400 gallons of propane and about 36.6 million BTU. The burntime endpoint divides that energy by an appliance’s BTU-per-hour input rating to give run time: that same 20 lb cylinder runs a 30,000 BTU/hr patio heater about 14 hours, and an optional hours-per-day turns it into days. The refill endpoint costs a fill from a price per gallon, gives the cost per 100,000 BTU so you can compare propane to natural gas or electricity, and — with an appliance rating — the running cost per hour. Everything is computed locally and deterministically, so it is instant and private. Ideal for home-energy, HVAC, RV, off-grid, grilling and outdoor-living app developers, fuel-cost and tank-monitor tools, and propane-delivery calculators. Pure local computation — no key, no third-party service, instant. US units. Live, nothing stored. 3 compute endpoints. For vehicle fuel economy or the ideal gas law use a different API.

api.oanor.com/propane-api

Moist-air (psychrometric) thermodynamics as an API, computed locally and deterministically. The dewpoint endpoint computes the dew-point temperature and the saturation and actual water-vapour pressures from a dry-bulb temperature and relative humidity, using the Magnus-Tetens relation over water, es = 6.112·exp(17.62·T/(243.12+T)) hPa — the dew point is the temperature to which air must cool for water vapour to start condensing. The humidity-ratio endpoint computes the humidity ratio (mixing ratio) W = 0.621945·Pw/(P−Pw), the specific and absolute humidity, the vapour pressure and the moist-air enthalpy h = 1.006·T + W·(2501 + 1.86·T) kJ per kg of dry air, at any total pressure (default sea-level 101325 Pa). The wet-bulb endpoint computes the wet-bulb temperature with the Stull (2011) empirical fit and the wet-bulb depression, the gap between dry- and wet-bulb that widens as the air gets drier. Temperatures are in °C, relative humidity in %, pressures in Pa. Everything is computed locally and deterministically, so it is instant and private. Ideal for HVAC, building-physics, meteorology, drying, greenhouse and data-centre-cooling app developers, comfort and condensation-risk tools, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is moist-air psychrometrics; for ASHRAE ventilation airflow use a ventilation API, for the WBGT heat-stress index a WBGT API and for the standard atmosphere an atmosphere API.

api.oanor.com/psychrometric-api

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.

api.oanor.com/ventilation-api

Heating and cooling degree-day maths as an API, computed locally and deterministically. The daily endpoint computes the heating degree days, HDD = max(0, base − mean), and the cooling degree days, CDD = max(0, mean − base), for a single day from a base temperature and the daily mean — or the minimum and maximum, since the mean is taken as their average. The period endpoint sums the degree days over a list of daily temperatures (means or min/max pairs), returning the total HDD and CDD, the count of heating and cooling days and the average temperature — the standard way to characterise a heating or cooling season. The energy endpoint turns degree days into an energy estimate: the heat delivered is UA·DD·24/1000 kWh from the building heat-loss coefficient, the fuel or electricity input is that divided by the boiler efficiency (or a heat-pump COP), and — with an energy price — the cost. Everything is computed locally and deterministically, so it is instant and private. Ideal for building-energy, HVAC and facilities tools, heating-bill and fuel-budget estimation, weather-normalisation and energy-benchmarking apps, and engineering education. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is degree-day demand estimation; for U-value and heat-loss fabric calculations use a U-value API.

api.oanor.com/degreeday-api

Matemáticas de dimensionamiento de HVAC como API, calculadas local y determinísticamente a partir de factores estándar de regla general. El endpoint de refrigeración estima la carga del aire acondicionado para una habitación — en BTU por hora, toneladas de refrigeración y kilovatios — a partir del área del piso (en pies cuadrados o metros, o largo × ancho) usando una línea base de aproximadamente 20 BTU/h por pie cuadrado, con ajustes por el número de ocupantes, una cocina, exposición solar y altura del techo. El endpoint de calefacción estima la carga de calefacción a partir del área y una zona climática (templada a muy fría) o un BTU personalizado por pie cuadrado. El endpoint de conversión convierte entre BTU por hora, toneladas de refrigeración, kilovatios y vatios (una tonelada = 12,000 BTU/h ≈ 3.517 kW). Todo se calcula local y determinísticamente, por lo que es instantáneo y privado. Estas son estimaciones de regla general al estilo EnergyStar — se recomienda un cálculo de carga Manual J adecuado que tenga en cuenta el aislamiento, las ventanas y el clima local para una instalación real. Ideal para herramientas de HVAC y mejoras del hogar, guías de dimensionamiento de aires acondicionados y calefactores, aplicaciones de hogar inteligente y energía, y cotizaciones para contratistas. Cálculo local puro — sin clave, sin servicio de terceros, instantáneo. En vivo, nada almacenado. 3 endpoints. Esto es dimensionamiento de HVAC; para el costo de funcionamiento de electrodomésticos, use una API de costo de energía.

api.oanor.com/hvac-api