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Terms of Use

Subcool

Terms of Use for Subcool

Subcool - HVAC Field Calculator Published by OFO Labs

Last Updated: August 2026

Please read these Terms of Use carefully before using Subcool. By downloading or using the app, you agree to these terms.

Acceptance of Terms

By accessing or using Subcool, developed and published by OFO Labs, you agree to be bound by these Terms of Use. If you do not agree, do not use the app.

License

OFO Labs grants you a limited, non-exclusive, non-transferable, revocable license to use Subcool on any Apple device you own or control, subject to the Apple Media Services Terms and Conditions. Subcool is a professional tool and using it in the course of your trade is exactly what it is for.

What Subcool Does

Subcool performs calculations on measurements you take yourself. Given a refrigerant and a gauge pressure it returns the saturation temperature interpolated from that refrigerant manufacturer's published pressure-temperature chart, and from there superheat and subcooling. It also computes airflow, duct sizes, psychrometric properties, electrical values and gas appliance figures from published engineering equations, and it can store the readings you enter and produce a report from them.

What Subcool Is Not

Subcool is a calculator. It is not a certification, an inspection, or a substitute for training.

  • It does not measure anything. Every value it works from is one you entered.
  • It does not certify that equipment is correctly charged, safe, efficient or compliant with any code or standard.
  • It gives no instructions for handling refrigerant, and none for A2L refrigerants in particular. Where it states a safety classification it is repeating a published fact and deferring to the equipment manufacturer and your local requirements on everything else.
  • Its diagnostic notes describe what a set of readings commonly suggests. They are a starting point for your own diagnosis and never a conclusion about a specific machine.
  • It reproduces no code tables. There is deliberately no electrical ampacity table and no gas pipe sizing table, because those belong in the codes that publish them.

Always check a result against the data on the unit and the manufacturer's own literature before you act on it. You are the qualified person; Subcool is arithmetic.

Accuracy

Refrigerant saturation values are interpolated between rows of charts published by Honeywell and Chemours. Psychrometric properties come from the equations in the ASHRAE Handbook of Fundamentals and duct friction from Darcy-Weisbach with the Colebrook-White friction factor. These are the recognised sources, and Subcool names the source alongside the result so you can check it.

Interpolation, rounding and the resolution of the published charts all introduce small differences. OFO Labs makes no warranty that a result is exact, and no warranty that it is appropriate for any particular piece of equipment.

Your Data

Subcool stores what you enter on your device and nowhere else. There is no account and no server. You are responsible for the records you keep in it, including any customer details, and for exporting anything you need to keep before you delete the app. See the Privacy Policy for the detail.

Purchases

Subcool is free to download and use for charging work. Subcool Pro is a single non-consumable in-app purchase that unlocks duct sizing, full psychrometrics, the combustion checks, saved job records and the PDF and CSV export. It is a one-time payment, not a subscription, and it does not expire.

Purchases are processed by Apple and governed by the Apple Media Services Terms and Conditions. Refunds are handled by Apple, not by OFO Labs.

Limitation of Liability

To the fullest extent permitted by law, OFO Labs is not liable for any loss, damage, cost or injury arising from the use of Subcool or from reliance on any figure it produces, including damage to equipment, loss of refrigerant, wasted materials, or any commercial loss. Subcool is provided as is and without warranty of any kind.

Nothing in these terms limits liability that cannot lawfully be limited.

Changes

These terms may change. The date at the top will change with them, and continuing to use the app means accepting the revised terms.

Contact

OFO Labs ofolabs@gmail.com