# FieldCalc: HVAC & Plumbing — Duct, charge and pipe math

> Duct, charge and pipe math (iPhone/iPad app by SG APPs.)

- Source: https://appshunter.io/ios/app/fieldcalc-hvac-and-plumbing/id6797057864 (this page in markdown: same URL + `.md`)
- Developer: [SG APPs](https://appshunter.io/developer/1507658418)
- Category: Productivity, Reference
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 13.0 · 27 MB
- Languages: American English
- Released: 2026-09-29
- Data updated: 2026-10-31

## What is FieldCalc?

FieldCalc is the calculator set for people who actually install and service the equipment. It is built around the numbers you reach for on a call — duct sizes, charge, load, pipe volume, grade — and it runs entirely on the phone.

No signal in the crawlspace. No account. No data leaving the device.

AIR SIDE
---------
• Ductulator — round and rectangular sizing, with velocity and friction rate updating as you type, plus the next standard size up
• Ventilation & ACH — air changes, outdoor air rates and exhaust requirements
• Airflow by temperature rise — CFM from furnace rise, the fast field check

REFRIGERATION
----------------
• PT chart — 16 refrigerants with bubble, dew and glide, from CoolProp's Helmholtz equations of state rather than a typed-in table
• Superheat — target superheat for fixed orifice and TXV systems, with live off-target and an explanation of what it means
• Subcooling — liquid side charging against nameplate

LOADS & EQUIPMENT
----------------------
• Block load — whole-house heating and cooling estimate with a full breakdown of where the load comes from, so you can see what is driving the number

PLUMBING
-----------
• Pipe volume — fill, weight and chlorination dosing
• Offset & rolling offset — travel, run and cut length for any angle
• Slope & grade — fall, percent grade and code minimums

UTILITIES
----------
• Unit converter — every unit the trade actually uses
• Reference library — copper, steel and PVC dimensions, duct tables and
  refrigerant properties, bundled in the app

WHY IT IS DIFFERENT
---------------------
Refrigerant properties are computed from real equations of state, not interpolated from a screenshot of a chart. Glide is shown for every blend, so you know when bubble and dew actually differ.

Every result shows its working. Tap the sigma to see the method, the inputs and the assumptions behind a number, because a calculator you cannot check is a calculator you cannot defend to an inspector.

Warnings are advisory, not blocking. If the velocity is high, FieldCalc says so and tells you the target it is comparing against — then gets out of the way.

Both unit systems, everywhere. Switch IP and SI per screen without losing your inputs.

HONEST ABOUT SCOPE
------------------------
The block load is a block estimate. It is a solid sizing sanity check and it shows you its assumptions, but it is not a substitute for a room-by-room Manual J when the job calls for one. FieldCalc tells you that on the screen rather than hiding it in a disclaimer.

Built for HVAC technicians, refrigeration techs, plumbers, sheet metal workers, service managers, estimators and apprentices.

Privacy Policy: https://www.mindzbase.com/privacy-policy
Terms of Use: https://www.mindzbase.com/terms-of-use

InApp and Subscription Info
---------------------------
Lifetime inApp purchase | $9.99

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Lifetime Access | $9.99 | one-time |


## Is FieldCalc safe?

Not enough ratings yet to assess FieldCalc.

## Is FieldCalc legit?

FieldCalc: HVAC & Plumbing appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for FieldCalc is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0 — 2026-09-29

No release notes.

## More apps by SG APPs

- [CISSP Prep](https://appshunter.io/ios/app/cissp-prep/id6740624648)
- [CompTIA A+ Prep App](https://appshunter.io/ios/app/comptia-a-plus-prep-app/id6741076350)
- [Network+ : CompTIA Exam Prep](https://appshunter.io/ios/app/network-plus-comptia-exam-prep/id6741431408)
- [Security+ : CompTIA Exam Prep](https://appshunter.io/ios/app/security-plus-comptia-exam-prep/id6741431430)
- [.NET Core : Interview Prep](https://appshunter.io/ios/app/net-core-interview-prep/id6742101259)
- [Smart Sleep Calculator](https://appshunter.io/ios/app/smart-sleep-calculator/id6744327999)

All apps by SG APPs: https://appshunter.io/developer/1507658418

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-31.*