# CO2 sensor vs Ear Spy Apps

The clearest difference is rating: Ear Spy Apps at 4.4 against CO2 sensor's 3.4. Ear Spy Apps also leads on update cadence (every 5 weeks vs every 12 months) and ratings volume (1.2K vs 7). CO2 sensor's advantage is in-app purchases (none vs 4). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Ear Spy Apps sells 4 in-app purchases, starting at $5.99 per 7 days. CO2 sensor asks for nothing beyond the download.

Ear Spy Apps holds the better App Store score, 4.4 against 3.4. That said, the two scores are not equally well evidenced: Ear Spy Apps has 1.2K ratings behind it against 7, so its average is the more settled of the two.

CO2 sensor ships an update every 12 months, Ear Spy Apps every 5 weeks. The most recent releases landed on October 3, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | CO2 sensor | Ear Spy Apps |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.4 (7 ratings)](https://appshunter.io/ios/app/co2-sensor/id1643286074/reviews) | **[4.4 (1.2K ratings)](https://appshunter.io/ios/app/ear-spy-apps-super-hearing/id6468564704/reviews)** |
| Number of ratings | 7 | **1.2K** |
| Positive reviews | — | 79.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 12 months | **Every 5 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 0 MB | 45 MB |
| Requires iOS | 15.6 | **14.0** |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [sighmon](https://appshunter.io/developer/377815161) | [Nino Gogoladze](https://appshunter.io/developer/1710106916) |

## What reviewers say

### CO2 sensor

[App page](https://appshunter.io/ios/app/co2-sensor/id1643286074)

Monitor CO2, temperature, and humidity levels in real-time using a Bluetooth sensor. Save readings with location data and sync them across Apple devices via iCloud. View historical data on a map.

**Highlights:** Real-time CO2, temperature, and humidity readings, Bluetooth sensor integration, Save readings with location, iCloud sync across devices, Map view of saved readings, Open source code available

**Features:** Vision Pro support

**In-app purchases:** none


### Ear Spy Apps

[App page](https://appshunter.io/ios/app/ear-spy-apps-super-hearing/id6468564704)

Securely hide private photos, videos, and files in a password-protected vault. Capture high-quality audio with advanced recording features, including long-range directional microphones and night vision. Enhance audio clarity and customize sound with EQ adjustments for professional-grade results.

**Highlights:** Secure private vault, Advanced audio recording, Long-range directional microphone, Night vision recording, Password protection, EQ adjustments

**Features:** macOS Compatibility

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unlimited Access - Weekly | $5.99 | per 7 days |
| Hearing Amplifier, SpyFall | $9.99 | per month |
| Hearing Amplifier - Ear Spy | $19.99 | per 3 months |
| Tape Recorder, SpyTec | $34.99 | per year |

**What reviewers like**

- 👍 Clear audio quality
- 🚀 Awesome app
- 👍 User-friendly
- 👍 Great features
- 👍 Helpful for hard of hearing

**What reviewers complain about**

- 🐛 Can't open existing files
- 🔒 Lots of ads in free version
- 🐛 Won't restore itself after reinstall
- 🐛 Paywall nags interfere with usage
- 🐛 No sound recording in free version

**Reported bugs**

- Can't open existing files
- No sound recording in free version
- Won't restore itself after reinstall

**Requested features**

- Longer free trial period
- Restore full access after reinstall
- Reduce ad frequency in free version


## Frequently asked questions

### Is CO2 sensor free?

CO2 sensor is free to download, with no in-app purchases.

### Is Ear Spy Apps free?

Ear Spy Apps is free to download, with in-app purchases available.

### Which has better reviews, CO2 sensor or Ear Spy Apps?

Ear Spy Apps is rated higher. CO2 sensor averages 3.4 out of 5 from 7 ratings, while Ear Spy Apps averages 4.4 from 1.2K ratings.

### Do CO2 sensor or Ear Spy Apps have ads?

Neither CO2 sensor nor Ear Spy Apps shows ads.

### Which is updated more often, CO2 sensor or Ear Spy Apps?

CO2 sensor ships an update every 12 months, and Ear Spy Apps every 5 weeks. Most recently, CO2 sensor was updated on October 3, 2026 and Ear Spy Apps on October 20, 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.*