Airkit: HVAC Calculator

Superheat, target charge, the ductulator, PT charts, static pressure and MCA — every calculation a working tech needs. Fast, offline, A2L-ready.

Airkit is the all-in-one HVAC calculator built for working technicians. Superheat and subcooling, refrigerant charging, the ductulator, PT charts, airflow, static pressure, and the electrical numbers — every calc you reach for on a service call, in one fast, offline app.

Built for modern systems. Airkit handles A2L refrigerants (R-454B, R-32, R-454C) with glide done right — dew point for superheat, bubble point for subcooling — alongside R-410A, R-22, R-134a and 15+ more.

CHARGING • Superheat & subcooling with live verdicts against your target • Target superheat from indoor wet bulb + outdoor dry bulb (fixed orifice / piston) • Delta T health check • Charging assistant — pass, add, or recover refrigerant

REFRIGERANT • PT chart — a pressure-temperature slider for 20+ refrigerants • Line set charge — ounces per foot for the actual run • A2L handling, oil pairing, and cylinder-color reference

AIRFLOW • Ductulator — round & rectangular duct sizing by friction rate or velocity • CFM per ton and target airflow • Static pressure designer — TESP, filter and coil drops, friction rate

ELECTRICAL • MCA / MOCP with copper wire sizing (NEC 2023) • Capacitor check — rated vs. measured, plus under-load microfarads • Ohm's Law and AC power

PLUS • Unit converter — pressure, vacuum microns, temperature, airflow, capacity, length and more • Offline reference: thermostat wiring, superheat/subcooling targets, duct velocity, line sets, ACR copper tube, refrigerant & oil pairing

WHY AIRKIT • Works fully offline — no signal in the mechanical room, no problem • No account, no sign-up • Fast, glove-friendly, and readable in the dark or in glare • Values consistent with NEC 2023 and ASTM B280 — always verify against the locally adopted code • Available in 22 languages

Free to use, with an optional Pro unlock for the complete refrigerant set and advanced tools.

Airkit is an informational aid for trained HVAC/R professionals. Always follow equipment nameplates, OEM literature, and local code.