HVAC Pro Calculator: NEC + P-T

HVAC Pro Calculator — BTU load sizing, duct calc, NEC voltage drop, refrigerant P-T charts, superheat & subcooling. Field tools for HVAC techs and electricians. Every formula cited (ASHRAE, NEC, SMACNA). No ads, no tracking. WHAT YOU GET — FREE • BTU & Cooling Load — Heat and cool sizing using ASHRAE-derived rules of thumb. Inputs for square footage, ceiling height, climate zone, occupancy, and sun exposure. • Duct Sizing — Manual D simplified using the ASHRAE friction-rate equation. Round and rectangular duct, equivalent-diameter solver, velocity check with noise warnings. • Unit Converter — BTU/hr ↔ kW ↔ tons of refrigeration, CFM ↔ L/s ↔ m³/h, °F ↔ °C, PSI ↔ kPa ↔ bar. Everything an HVAC tech converts in a day. UPGRADE TO PRO • Voltage Drop & Wire Size — NEC voltage-drop formula sized to NEC Table 310.16 ampacity. Single-phase or three-phase, copper or aluminum. Recommends the smallest AWG that meets both ampacity and your drop limit. • Refrigerant P-T Charts — Pressure ↔ temperature lookup for R-410A, R-32, R-454B, and R-22. Saturation tables baked from manufacturer data. Linear interpolation for any temp or pressure in range. • Superheat & Subcooling — Standard charging diagnostics using P-T tables. Status badge tells you at a glance if the system is on target, undercharged, or overcharged. • Sheet Metal Offset — Diagonal cuts and angles for duct transitions, per SMACNA HVAC Duct Construction Standards. • Unlimited Saved Jobs — Save every calculation by job name. Free tier saves up to 2; Pro unlocks unlimited. • PDF Export — One-tap PDF for customer estimates and code submittals. WHY PROS PICK HVAC PRO • Cited sources, not "approximate." Every formula in the app references its standard (ASHRAE, NEC, SMACNA, manufacturer P-T tables). Status badges flag when readings are out of range. • Field-readable design. Cool, high-contrast layout that works in direct sunlight and one-handed gloved typing. • No analytics, no ads, no upsell spam. Free tier is genuinely useful. Pro is genuinely valuable. • Apple-native. SwiftUI, dark mode, Dynamic Type, iPad split view, Apple Pencil — built for iPhone and iPad on iOS 17+. PRICING HVAC Pro is $9.99 / year with a 3-day free trial. One subscription unlocks every Pro calculator, unlimited saved jobs, and PDF export. Cancel anytime in Settings > Apple ID > Subscriptions. Auto-renews until canceled. — Built by PLAYRIOT LLC. Calculations are estimates intended for trade professional use. For code-compliant Manual J load submittals, use ACCA-certified software. Support: https://hvacprocalc.aiappnation.com Privacy: https://hvacprocalc.aiappnation.com/privacy Terms: https://hvacprocalc.aiappnation.com/terms