HVAC Pro Calculator: NEC + P-T

HVAC Pro Calculator — BTU load sizing, duct calc, NEC voltage drop, refrigerant P-T charts, superheat & subcooling, plus camera nameplate scanning. 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. Square footage, ceiling height, climate zone, occupancy, and sun exposure.
• Duct Sizing — Manual D simplified via the ASHRAE friction-rate equation. Round and rectangular duct, equivalent-diameter solver, velocity check with noise warnings.
• Unit Converter — BTU/hr ↔ kW ↔ tons, CFM ↔ L/s ↔ m³/h, °F ↔ °C, PSI ↔ kPa ↔ bar. Everything an HVAC tech converts in a day.
• Save up to 2 jobs — Name and store calculations locally. No account, no cloud.

UPGRADE TO PRO — 9 field calculators + camera nameplate scanning

• PlateScan — Point your camera at any condenser or furnace nameplate. On-device OCR reads the model and serial and decodes tonnage, manufacture date, and refrigerant type, then drops them straight into your calc. Works offline.
• Voltage Drop & Wire Size — NEC voltage-drop formula sized to NEC Table 310.16 ampacity. Single- or three-phase, copper or aluminum. Recommends the smallest AWG that meets both ampacity and your drop limit.
• Refrigerant P-T Charts — Pressure ↔ temperature for R-410A, R-32, R-454B, and R-22. Saturation tables baked from manufacturer data, interpolated for any temp or pressure in range.
• Superheat & Subcooling — Charging diagnostics off the P-T tables for fixed-orifice and TXV systems. Status badge flags on-target, undercharged, or overcharged at a glance.
• Refrigerant Charge — Adjusts the nameplate charge for non-standard line-set length (per Copeland AE 17-1335) and returns the exact amount to add or recover.
• System Capacity (ΔT) — Actual sensible capacity an installed system is delivering, from measured airflow and supply/return temperature split.
• Psychrometric — Give any two of dry bulb, wet bulb, RH, or dew point; returns the full state — humidity ratio, enthalpy, specific volume, and the remaining temperatures (ASHRAE Fundamentals Ch. 1).
• Fan Laws — Scales CFM, static pressure, and brake horsepower from a known operating point to a new RPM.
• Sheet Metal Offset — Diagonal cuts and angles for duct transitions, per SMACNA HVAC Duct Construction Standards.
• Capacitor Test — Actual μF of a run capacitor from in-circuit amps and volts, compared to nameplate with an ADD / OK / REPLACE verdict (±6%).
• Unlimited Saved Jobs — Remove the 2-job cap; save every calculation by job name.
• PDF Export — One-tap PDF for customer estimates and code submittals.

WHY PROS PICK HVAC PRO

• Cited sources, not "approximate." Every formula references its standard (ASHRAE, NEC, SMACNA, manufacturer P-T tables). Status badges flag when readings are out of range.
• Field-readable design. 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 — built for iPhone and iPad on iOS 17+.

PRICING

HVAC Pro is $19.99 / year (with a 3-day free trial) or $4.99 / month. One subscription unlocks every Pro calculator, PlateScan, 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.

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