# Rhythm Lighting vs CircadiaOS

The clearest difference is in-app purchases: Rhythm Lighting at none against CircadiaOS's 4. Rhythm Lighting also leads on ads (none vs shown) and iOS requirement (15.0 vs 18.0). CircadiaOS's advantage is update cadence (every 3 days vs every 2 weeks). On price and device support there is nothing between them.

Both are free to download. CircadiaOS sells 4 in-app purchases, starting at $9.99 per month. Rhythm Lighting asks for nothing beyond the download.

Rhythm Lighting ships an update every 2 weeks, CircadiaOS every 3 days. Both last shipped on October 24, 2026.

## The numbers

| Metric | Rhythm Lighting | CircadiaOS |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.5 (11 ratings)](https://appshunter.io/ios/app/circadiaos-sleep-tracker/id6761959749/reviews)** |
| Number of ratings | — | **11** |
| Positive reviews | — | 75.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 2 weeks | **Every 3 days** |
| Monetization | — | Free with in-app purchases |
| Size | 37 MB | 25 MB |
| Requires iOS | **15.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 17+ |
| Developer | [DT Concepts, LLC](https://appshunter.io/developer/1872148996) | [CircadiaOS LLC](https://appshunter.io/developer/1892208236) |

## What reviewers say

### Rhythm Lighting

[App page](https://appshunter.io/ios/app/rhythm-lighting/id6758312802)

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

**In-app purchases:** none


### CircadiaOS

[App page](https://appshunter.io/ios/app/circadiaos-sleep-tracker/id6761959749)

This app learns your body's ideal sleep temperature and automatically adjusts your smart thermostat throughout the night. It uses data from your wearable to personalize a four-phase temperature schedule for optimal sleep recovery. Requires a compatible smart thermostat and sleep-tracking wearable.

**Highlights:** Learns ideal sleep temperature, Personalized four-phase temperature schedule, Integrates with smart thermostats, Syncs with sleep-tracking wearables, Analyzes sleep quality, Two-week calibration period

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| CircadiaOS Lite Monthly | $9.99 | per month |
| CircadiaOS | $19.99 | per month |
| CircadiaOS Lite Yearly | $99.99 | per year |
| CircadiaOS | $159.99 | per year |


## Frequently asked questions

### Is Rhythm Lighting free?

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

### Is CircadiaOS free?

CircadiaOS is free to download, with in-app purchases available.

### Do Rhythm Lighting or CircadiaOS have ads?

CircadiaOS shows ads; Rhythm Lighting does not.

### Which is updated more often, Rhythm Lighting or CircadiaOS?

Rhythm Lighting ships an update every 2 weeks, and CircadiaOS every 3 days. Most recently, Rhythm Lighting was updated on October 24, 2026 and CircadiaOS on October 24, 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.*