# Solar Potential vs Postfach

The clearest difference is price: Postfach at Free against Solar Potential's $1.99. Postfach also leads on update cadence (daily vs every 8 days). Solar Potential's advantage is in-app purchases (none vs 1) and iOS requirement (13.0 vs 18.0). On ads and device support there is nothing between them.

Postfach is free to download; Solar Potential costs $1.99 up front. Postfach sells 1 one-off in-app purchase. Solar Potential asks for nothing beyond the download.

Solar Potential ships an update every 8 days, Postfach daily. The most recent releases landed on October 8, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Solar Potential | Postfach |
| --- | --- | --- |
| Price | $1.99 | **Free** |
| Positive reviews | 60.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 8 days | **Daily** |
| Monetization | Paid | — |
| Size | 1 MB | 19 MB |
| Requires iOS | **13.0** | 18.0 |
| Devices | iPhone, iPod | **iPhone, iPad, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [soft-evolution GmbH & Co. KG](https://appshunter.io/developer/320755965) | [esense GmbH](https://appshunter.io/developer/1545555949) |

## What reviewers say

### Solar Potential

[App page](https://appshunter.io/ios/app/solar-potential/id6448853706)

Estimate your solar energy generation and potential savings by simulating solar panels using your phone. Simply place your device in the planned panel position to get an instant estimate of yield in kWh and Euros, considering location, orientation, tilt, and weather trends.

**Highlights:** Simulate solar panel placement with phone, Estimate energy yield in kWh, Calculate potential savings in Euros, Consider orientation and tilt, Factor in long-term weather trends, Supports balcony power plants

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

**In-app purchases:** none


### Postfach

[App page](https://appshunter.io/ios/app/postfach-private-mail/id6809901522)

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Postfach Pro | $22.99 | one-time |


## Frequently asked questions

### Is Solar Potential free?

Solar Potential costs $1.99, with no in-app purchases.

### Is Postfach free?

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

### Do Solar Potential or Postfach have ads?

Neither Solar Potential nor Postfach shows ads.

### Which is updated more often, Solar Potential or Postfach?

Solar Potential ships an update every 8 days, and Postfach daily. Most recently, Solar Potential was updated on October 8, 2026 and Postfach on October 13, 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.*