# Ref Tools vs Fixture Unit Calc Plumb

The clearest difference is price: Ref Tools at Free against Fixture Unit Calc Plumb's $0.99. Ref Tools also leads on in-app purchases (none vs 1) and ads (none vs shown). Fixture Unit Calc Plumb's advantage is iOS requirement (13.0 vs 15.0). On update cadence and device support there is nothing between them.

Ref Tools is free to download; Fixture Unit Calc Plumb costs $0.99 up front. Fixture Unit Calc Plumb sells 1 one-off in-app purchase. Ref Tools asks for nothing beyond the download.

Ref Tools ships an update every 5 weeks, Fixture Unit Calc Plumb every 3 weeks. The most recent releases landed on September 29, 2026 and September 17, 2026 respectively.

## The numbers

| Metric | Ref Tools | Fixture Unit Calc Plumb |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | **[3.9 (52 ratings)](https://appshunter.io/ios/app/ref-tools/id472312541/reviews)** | — |
| Number of ratings | **52** | — |
| Positive reviews | 57.6% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 5 weeks | **Every 3 weeks** |
| Monetization | Free | — |
| Size | 98 MB | 33 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Danfoss A/S](https://appshunter.io/developer/423984644) | [Rizvan Adzhoian](https://appshunter.io/developer/1891746079) |

## What reviewers say

### Ref Tools

[App page](https://appshunter.io/ios/app/ref-tools/id472312541)

This app provides HVACR technicians with essential tools and information for field service. It includes refrigerant calculators, troubleshooting guides, product finders, and access to spare parts. Listen to educational podcasts to enhance your knowledge on the go.

**Highlights:** Refrigerant Slider for P/T calculations, Solenoid valve coil testing tool, Refrigeration system troubleshooting guide, Product data finder, Spare parts ordering, Low-GWP refrigerant comparison, TXV Superheat optimization, Educational podcasts

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 👍 Useful tool for HVAC/R techs
- 👍 Great idea for an app
- 👍 Best refrigeration and hvac app
- 👍 Useful App for HVACR
- 👍 Brilliant app

**What reviewers complain about**

- 🐛 Crashes instantly on launch
- 🐛 App won’t open on iPhone
- 🐛 Flashes up and disappears
- 🐛 Cannot open app
- 🐛 Immediately shuts off

**Reported bugs**

- CRASHED instantly on Mac Mini M4
- App won’t open on iPhone
- App flashes up and disappears
- Cannot open app
- Immediately shuts off since recent release

**Requested features**

- More residential AC information
- Troubleshooter for Residential & Commercial
- Add SP22 refrigerant
- Add R-11 refrigerant
- Add R-123 range down to 40 degrees


### Fixture Unit Calc Plumb

[App page](https://appshunter.io/ios/app/fixture-unit-calc-plumb/id6765783513)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Unlock | $2.99 | one-time |


## Frequently asked questions

### Is Ref Tools free?

Ref Tools is free to download, with no in-app purchases.

### Is Fixture Unit Calc Plumb free?

Fixture Unit Calc Plumb costs $0.99, and also offers in-app purchases.

### Do Ref Tools or Fixture Unit Calc Plumb have ads?

Fixture Unit Calc Plumb shows ads; Ref Tools does not.

### Which is updated more often, Ref Tools or Fixture Unit Calc Plumb?

Ref Tools ships an update every 5 weeks, and Fixture Unit Calc Plumb every 3 weeks. Most recently, Ref Tools was updated on September 29, 2026 and Fixture Unit Calc Plumb on September 17, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*