HVAC Calculator - FieldCalc
Superheat, R-454B & Duct Tools
Only for iPhone
Free · In‑App Purchases · Designed for iPhone. Not verified for macOS.
iPhone
R-410A is out, R-454B is in. Get PT charts, superheat & subcooling, duct sizing, psychrometrics & load estimates — all offline, one app. Built for HVAC technicians.
FieldCalc HVAC is the all-in-one field calculator for HVAC technicians. From R-454B PT lookups to duct sizing and load estimates — everything you need, working offline, right in your pocket.
► R-454B READY
The industry is switching from R-410A to R-454B. Get instant pressure-temperature data for R-454B, R-32, R-410A, plus 10 more refrigerants (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.
► DUCT SIZING
Size round and rectangular ducts using the equal-friction method (ASHRAE Fundamentals / Manual D methodology). Enter airflow and friction rate — get diameter, velocity, 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 mini psychrometric chart with the state point plotted.
► 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.
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, pin your favorites, add notes for each job
• Export professional PDF reports
• 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 5 calculators, full refrigerant library (13), history, PDF export, and all future updates.
No subscription. No ads. No data collection. Buy once, own forever.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
What's New in v1.0.1:
• R-454B & A2L refrigerant support — ready for the 2025 phase-out
• Enhanced PT chart with bubble/dew pressure glide display
• Superheat & subcooling with target-range diagnostics
• Duct sizing (equal-friction method) and Manual J load estimates
• Psychrometrics: dew point, wet bulb, enthalpy
• Full unit converter: °F/°C, PSIG/kPa, CFM/m³·h, BTU/kW
• History with notes, pinning, and PDF export
• 100% offline — no internet needed in the field
No subscription. No ads. Buy once, own forever.
The developer, 静 李, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- 静 李
- Size
- 5.2 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- FieldCalc HVAC Pro $9.99
- Copyright
- © 2026 jing