# Ref Tools vs Zerk

The clearest difference is rating: Zerk at 5.0 against Ref Tools's 3.9. Ref Tools's advantage is ratings volume (52 vs 1). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Zerk holds the better App Store score, 5.0 against 3.9. That said, the two scores are not equally well evidenced: Ref Tools has 52 ratings behind it against 1, so its average is the more settled of the two.

Ref Tools ships an update every 5 weeks, Zerk monthly. The most recent releases landed on October 7, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Ref Tools | Zerk |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.9 (52 ratings)](https://appshunter.io/ios/app/ref-tools/id472312541/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/zerk-ai/id6792633785/reviews)** |
| Number of ratings | **52** | 1 |
| Positive reviews | 57.6% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 5 weeks | **Monthly** |
| Monetization | Free | Free |
| Size | 98 MB | 16 MB |
| Requires iOS | **15.0** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Danfoss A/S](https://appshunter.io/developer/423984644) | [晨阳 栗](https://appshunter.io/developer/6784480667) |

## 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


### Zerk

[App page](https://appshunter.io/ios/app/zerk-ai/id6792633785)

Diagnose and fix home appliance issues with AI. Scan your appliance's model label, describe the problem, and receive instant repair guidance and compatible parts. Avoid unnecessary service calls and save money.

**Highlights:** AI-powered diagnosis, Model identification via camera, Step-by-step repair guidance, Compatible parts marketplace, Repair ticket submission, Live chat support, Order management

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

**In-app purchases:** none


## Frequently asked questions

### Is Ref Tools free?

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

### Is Zerk free?

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

### Which has better reviews, Ref Tools or Zerk?

Zerk is rated higher. Ref Tools averages 3.9 out of 5 from 52 ratings, while Zerk averages 5.0 from 1 ratings.

### Do Ref Tools or Zerk have ads?

Neither Ref Tools nor Zerk shows ads.

### Which is updated more often, Ref Tools or Zerk?

Ref Tools ships an update every 5 weeks, and Zerk monthly. Most recently, Ref Tools was updated on October 7, 2026 and Zerk on October 1, 2026.

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