# HygieneKey vs SMART_AROMA

The clearest difference is review sentiment: SMART_AROMA at 100% against HygieneKey's 50%. SMART_AROMA also leads on update cadence (every 8 days vs every 2 months). HygieneKey's advantage is iOS requirement (8.0 vs 11.0). On price, ads, in-app purchases and monetization model there is nothing between them.

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

HygieneKey ships an update every 2 months, SMART_AROMA every 8 days. The most recent releases landed on September 23, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | HygieneKey | SMART_AROMA |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.0 (2 ratings)](https://appshunter.io/ios/app/smart-aroma/id1627724129/reviews)** |
| Number of ratings | — | **2** |
| Positive reviews | 50.0% of reviews | **100.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 8 days** |
| Monetization | Free | Free |
| Size | 59 MB | 32 MB |
| Requires iOS | **8.0** | 11.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [春华 赖](https://appshunter.io/developer/1604536904) | [萍萍 刘](https://appshunter.io/developer/1626043006) |

## What reviewers say

### HygieneKey

[App page](https://appshunter.io/ios/app/hygienekey/id1178896230)

Control smart devices integrated with a special chip through your mobile. Easily program machines, manage schedules, monitor battery, and set refill life. Save and import device settings as profiles for quick setup.

**Highlights:** Profile setting and import, Battery status indication, Refill life setting and status, Working schedule setting, Normal/Peak time options, Device reset and service span setting, Password support

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

**In-app purchases:** none


### SMART_AROMA

[App page](https://appshunter.io/ios/app/smart-aroma/id1627724129)

Manage your smart fragrance device remotely using your smartphone. Adjust fan speed, set fragrance intensity, and customize device settings without needing an internet connection.

**Highlights:** Device search and add, Rename and remark devices, Adjust fan wind/power, Set fragrance density, Password protection

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is HygieneKey free?

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

### Is SMART_AROMA free?

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

### Do HygieneKey or SMART_AROMA have ads?

Neither HygieneKey nor SMART_AROMA shows ads.

### Which is updated more often, HygieneKey or SMART_AROMA?

HygieneKey ships an update every 2 months, and SMART_AROMA every 8 days. Most recently, HygieneKey was updated on September 23, 2026 and SMART_AROMA on October 17, 2026.

---

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