# SunSpan vs Aerzeit

The clearest difference is in-app purchases: SunSpan at none against Aerzeit's 1. On price, rating, ratings volume and update cadence there is nothing between them.

Both are free to download. Aerzeit sells 1 in-app purchase, starting at $9.99 per year. SunSpan asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for SunSpan against 5.0 for Aerzeit. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

SunSpan ships an update every 2 days, Aerzeit every 3 days. Both last shipped on October 31, 2026.

## The numbers

| Metric | SunSpan | Aerzeit |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/sunspan/id6761731642/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/aerzeit-when-to-open-windows/id6787749300/reviews) |
| Number of ratings | 1 | 1 |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 3 days |
| Monetization | **Free** | Freemium |
| Size | 6 MB | 27 MB |
| Requires iOS | **16.0** | 16.4 |
| Devices | iPhone, iPad | **iPhone, iPad, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [Mykhailo Chelnokov](https://appshunter.io/developer/1891136089) | [Samuel Harrold](https://appshunter.io/developer/6775297361) |

## What reviewers say

### SunSpan

[App page](https://appshunter.io/ios/app/sunspan/id6761731642)

Visualize an entire year of daylight, sunrise, sunset, and twilight on a single, intuitive chart. Easily inspect daily solar times and phases by tapping or dragging across the visual representation. Offers detailed insights into seasonal changes and astronomical events.

**Highlights:** Full-year daylight chart, Eight-stop twilight gradient, Inspect daily solar times, DST transitions marked, Location picker via map/GPS, Automatic time zone resolution

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

**In-app purchases:** none


### Aerzeit

[App page](https://appshunter.io/ios/app/aerzeit-when-to-open-windows/id6787749300)

This app analyzes outdoor conditions for the next 48 hours to identify optimal times for ventilation. It allows customization of temperature ranges and environmental factors like rain, humidity, and pollen to help you decide when to open windows.

**Highlights:** 48-hour outdoor condition forecast, Customizable temperature ranges, Rain, humidity, wind, air quality, pollen filters, UV and sun position tracking, Apple Watch app and complication, Home Screen widget, Multi-language support

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Aerzeit Premium | $9.99 | per year |


## Frequently asked questions

### Is SunSpan free?

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

### Is Aerzeit free?

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

### Which has better reviews, SunSpan or Aerzeit?

SunSpan and Aerzeit are both rated 5.0 out of 5 on the App Store, from 1 and 1 ratings respectively.

### Do SunSpan or Aerzeit have ads?

Neither SunSpan nor Aerzeit shows ads.

### Which is updated more often, SunSpan or Aerzeit?

SunSpan ships an update every 2 days, and Aerzeit every 3 days. Most recently, SunSpan was updated on October 31, 2026 and Aerzeit on October 31, 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.*