# CO2 sensor vs Census Scan

The clearest difference is update cadence: Census Scan at daily against CO2 sensor's every 12 months. CO2 sensor's advantage is device support (4 vs 1) and iOS requirement (15.6 vs 17.0). On price, 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.

CO2 sensor ships an update every 12 months, Census Scan daily. The most recent releases landed on October 24, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | CO2 sensor | Census Scan |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.4 (7 ratings)](https://appshunter.io/ios/app/co2-sensor/id1643286074/reviews)** | — |
| Number of ratings | **7** | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 12 months | **Daily** |
| Monetization | Free | — |
| Size | 0 MB | 1 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [sighmon](https://appshunter.io/developer/377815161) | [Keith Rowell](https://appshunter.io/developer/6797726533) |

## 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


### Census Scan

[App page](https://appshunter.io/ios/app/census-scan/id6797726531)

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

**In-app purchases:** none


## Frequently asked questions

### Is CO2 sensor free?

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

### Is Census Scan free?

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

### Do CO2 sensor or Census Scan have ads?

Neither CO2 sensor nor Census Scan shows ads.

### Which is updated more often, CO2 sensor or Census Scan?

CO2 sensor ships an update every 12 months, and Census Scan daily. Most recently, CO2 sensor was updated on October 24, 2026 and Census Scan on October 25, 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.*