
HVAC Calculator: Superheat P/T
Subcooling, PT Chart, Duct CFM
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About
The HVAC technician's calculator that works where you do - on the rooftop, in the mechanical room, in the dead zone.
HVAC Tech is a fast, no-nonsense field calculator for technicians, installers, estimators, and apprentices. Six pro calculators, grounded in published refrigerant data and standard field methods, all running 100% on your phone. No account. No login. No internet. Just answers.
FULLY OFFLINE - ALWAYS
Rooftops, crawlspaces, new construction with no service - HVAC Tech needs zero signal. Every P/T table, every formula, every result is computed on-device. Your data never leaves your phone because there's nothing to send.
NOW IN SPANISH TOO
The whole app is also in Spanish: every calculator, every note, every diagnosis. It follows your iPhone's language automatically.
SIX PRO CALCULATORS
- Superheat: target (fixed-orifice charging chart or TXV range) vs. actual, with a charge read and the saturation temperature.
- Subcooling: target vs. actual, with a charge read.
- Refrigerant P/T Chart: pressure to saturation temperature, with separate bubble and dew points for glide blends.
- Delta-T: supply/return temperature split vs. a humidity-based target range, with typical-cause guidance.
- Duct Sizing: CFM to round or rectangular duct size and air velocity.
- Airflow & Tonnage: CFM to tons and back (400 CFM/ton, adjustable) plus fan-law RPM changes (CFM, static, and BHP).
FREE FOREVER
All six calculators, unlimited use, on R-410A and R-22 - no trial, no ads, no sign-in. Plus up to three saved jobs.
ONE-TIME PRO. NO SUBSCRIPTION. EVER.
Unlock HVAC Tech Pro once for $9.99 and keep it:
- Every refrigerant: R-454B, R-32, R-134a, R-404A and R-407C - the A2L blends shipping in new equipment and the commercial ones - across superheat, subcooling and the P/T chart.
- Glide-aware readings: separate bubble and dew points on every blend.
- Unlimited saved jobs.
- PDF and share export.
One payment, handled by Apple. No monthly fee, no renewal.
SAVE THE JOB
Tag any reading as a saved job - unit, call, and the numbers - one tap away.
HVAC Tech is an estimation aid and is not a substitute for proper diagnostic procedures. Always verify results against the manufacturer's charging charts and target values.
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What's New in HVAC Calculator
1.3.0
October 24, 2026
• Now in Spanish too: the whole app, every calculator and every note. Ahora en español. • New in Settings: rate HVAC Tech or share it with a coworker in one tap. • Layout polish on the calculator grid.
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Subscriptions & In-App Purchases
$9.99
HVAC Tech Pro
Unlimited saved jobs and PDF / share export.





