Support

Contact us

Found a bug, want a feature, or think a number looks off? Email hello@pairmind.dev and include your iOS version and, if it's about a calculation, the exact inputs you used — we verify every report against published reference data.

Frequently asked questions

Does the app work offline?

Yes — completely. Every calculator, saved job, and PDF report works with no signal at all. Airplane mode in a mechanical room is a supported workflow, not a fallback.

Which refrigerants are included?

R-410A is free forever. Pro adds R-32, R-454B, R-22, R-134a, and R-407C. Pressure–temperature data is computed from NIST-published equations of state, with correct dew-line superheat and bubble-line subcooling for blends.

How do I restore a purchase on a new phone?

Open the paywall from any Pro feature and tap Restore Purchases. Make sure you're signed into the same Apple Account you bought with. If it doesn't come back, email us.

How do I cancel a subscription?

Subscriptions are managed by Apple: open Settings → your name → Subscriptions on your iPhone, or visit apps.apple.com/account/subscriptions. Deleting the app does not cancel a subscription. The lifetime unlock is a one-time purchase — nothing to cancel.

My PDF report is missing my company name

Open the Jobs tab and edit the technician details — your name and company are stored on your device and stamped onto every report you export.

Is the load estimate a Manual J?

No. The load estimator is clearly labeled a rule-of-thumb for quick sanity checks. For design work, use a full ACCA Manual J/D/S calculation.

Accuracy & data sources

Refrigerant tables are computed from NIST-published Helmholtz equations of state (the same models behind REFPROP), duct friction uses the Colebrook–White equation with real roughness values for sheet metal and flex, and airflow formulas follow standard ASHRAE practice. The app is a reference tool for trained technicians — always verify against manufacturer specifications.

Privacy

The app has no accounts and your calculations never leave your phone. Full details in the privacy policy.