The professional HVAC calculator for technicians and contractors. Superheat, subcooling, charge by weight, R-454B PT charts, duct sizing, load estimates, and psychrometrics — seven field-ready tools, all offline, in one app. Whether you're charging a system with R-454B, checking superheat with your manifold gauge, sizing a duct run, or estimating cooling load for a new install, FieldCalc HVAC gives you instant, transparent answers — no internet required. ► R-454B & A2L READY The industry is switching from R-410A to R-454B and other low-GWP A2L refrigerants. Get instant pressure-temperature data for R-454B, R-32, R-410A, plus 13 more refrigerants (R-452B, R-1234ze, R-290, R-600a, R-134a, R-22, R-404A, R-407C, R-448A, R-449A, R-507A, R-1234yf, R-452A, R-513A). Drag the temperature slider and see bubble/dew pressures in real time. Includes GWP and ODP data for every refrigerant. ► SUPERHEAT & SUBCOOLING Verify refrigerant charge on the spot. Enter suction or liquid pressure, line temperature, and your target — get instant superheat or subcooling with a clear status indicator (green/amber/red) and diagnostic guidance. ► CHARGE BY WEIGHT Weigh in the total charge: enter the nameplate charge, factory and actual line-set lengths, and liquid line size — get the adjusted total in lb & oz with a scale-ready target. Default per-foot rates are theoretical and editable to match your OEM install manual. ► DUCT SIZING Size round and rectangular ducts using the equal-friction method (ASHRAE Fundamentals / Manual D methodology). Enter airflow (CFM) and friction rate — get diameter, velocity (FPM), and a velocity-range check for main vs. branch ducts. ► LOAD ESTIMATE Quick cooling load estimates using Manual J methodology (simplified). Enter floor area, climate zone, windows, occupants, and appliances — get total BTU/h, tons, and a recommended unit size with a breakdown bar. ► PSYCHROMETRICS Calculate dew point, wet bulb, enthalpy, humidity ratio, and vapor pressure from dry-bulb temperature and relative humidity. Includes a full interactive psychrometric chart — drag the state point and watch wet-bulb & enthalpy update live. ► UNIT CONVERTER Convert between °F/°C/K, PSIG/kPa/bar/MPa, CFM/m³·h/L/s, and BTU/h/kW/tons/hp — instantly, with conversion formulas shown. ► HOME-SCREEN WIDGET Add the PT widget to your Home Screen — pick a refrigerant and see saturation pressures at a glance. Tap it to jump straight into the chart. WHY FIELD CALC HVAC? • Works 100% offline — no internet needed on the roof or in the mechanical room • Every calculation shows its work — formulas, substitution, and standard references • Save calculations to history, group them by job, pin your favorites, add notes • Export professional PDF reports with your client info as the letterhead • Clean, modern interface designed for one-handed field use • Light & dark themes DATA SOURCES Refrigerant PT data is factual physical property data sourced from manufacturer publications (Honeywell, Chemours, Arkema), Hudson Technologies PT charts, and NIST Refprop. Calculations reference ASHRAE Fundamentals and ACCA Manual J/D methodology. FieldCalc HVAC is not affiliated with or endorsed by ASHRAE or ACCA. FREE vs PRO Free: Unit Converter, PT Charts (3 refrigerants: R-454B, R-32, R-410A) Pro ($9.99 one-time): All 6 calculators, full refrigerant library (17), history, PDF export, and all future updates. No subscription. No ads. No data collection. Buy once, own forever.
Utilities · iPhone, iPad · Free
