# SunStem vs E

The clearest difference is in-app purchases: SunStem at none against E's 3. SunStem also leads on ads (none vs shown) and update cadence (weekly vs every 3 weeks). E's advantage is device support (4 vs 2) and iOS requirement (15.0 vs 17.0). On price there is nothing between them.

Both are free to download. E sells 3 in-app purchases, starting at $2.99 per month. SunStem asks for nothing beyond the download.

SunStem ships an update weekly, E every 3 weeks. Both last shipped on October 15, 2026.

## The numbers

| Metric | SunStem | E |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | **Weekly** | Every 3 weeks |
| Size | 7 MB | 37 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Dmitriy Motorin](https://appshunter.io/developer/1495533596) | [Mohamed Mubarak](https://appshunter.io/developer/6787548629) |

## What reviewers say

### SunStem

[App page](https://appshunter.io/ios/app/sunstem-solar-calculator/id6787007719)

**Features:** macOS Compatibility

**In-app purchases:** none


### E

[App page](https://appshunter.io/ios/app/e-light-circuit-simulator/id6787548627)

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Monthly | $2.99 | per month |
| Pro Quarterly | $7.99 | per 3 months |
| Pro Yearly | $24.99 | per year |


## Frequently asked questions

### Is SunStem free?

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

### Is E free?

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

### Do SunStem or E have ads?

E shows ads; SunStem does not.

### Which is updated more often, SunStem or E?

SunStem ships an update weekly, and E every 3 weeks. Most recently, SunStem was updated on October 15, 2026 and E on October 15, 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.*