# LightFi Air vs HiiTRAIN

The clearest difference is iOS requirement: LightFi Air at 12.4 against HiiTRAIN's 16.2. 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.

LightFi Air ships an update every 3 months, HiiTRAIN every 2 months. The most recent releases landed on September 29, 2026 and October 28, 2026 respectively.

## The numbers

| Metric | LightFi Air | HiiTRAIN |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 2 months** |
| Monetization | Free | — |
| Size | 17 MB | 78 MB |
| Requires iOS | **12.4** | 16.2 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [LightFi Limited](https://appshunter.io/developer/1598090866) | [Hii Gym Limited](https://appshunter.io/developer/1736730594) |

## What reviewers say

### LightFi Air

[App page](https://appshunter.io/ios/app/lightfi-air/id1598090864)

Monitor your indoor air quality by displaying live Carbon Dioxide (CO₂) levels and other sensor data from connected devices. The app helps you understand your environment's impact on health, well-being, and productivity, suggesting actions like increasing ventilation when levels are high.

**Highlights:** Live CO₂ level display, Monitors multiple sensors, Customizable sensor names, Sorts sensors by distance, Health and productivity insights

**Features:** macOS Compatibility

**In-app purchases:** none


### HiiTRAIN

[App page](https://appshunter.io/ios/app/hiitrain/id6760403578)

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

**In-app purchases:** none


## Frequently asked questions

### Is LightFi Air free?

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

### Is HiiTRAIN free?

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

### Do LightFi Air or HiiTRAIN have ads?

Neither LightFi Air nor HiiTRAIN shows ads.

### Which is updated more often, LightFi Air or HiiTRAIN?

LightFi Air ships an update every 3 months, and HiiTRAIN every 2 months. Most recently, LightFi Air was updated on September 29, 2026 and HiiTRAIN on October 28, 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.*