Aerzeit: Window Airing Timer

Know the right moments to open your windows for fresh air — timed around the weather, so you open up when it's worth it and rain-free. No accounts, no tracking.

Aerzeit tells you when to open your windows so outside air becomes inside air at the temperature you want. It reads the local forecast and points to the moments worth opening up — working around the weather so you're not airing the house into a shower.

WHAT IT DOES

Pick the outdoor temperature range you'd be happy to let in. Aerzeit watches the local 48-hour forecast and tells you when conditions match — twice a day, morning and evening. Turn on the rain filter to skip the openings when showers are forecast, so you only hear about the windows of time actually worth using. Optional filters for humidity, wind, air quality, pollen and UV let you tune it to what matters to you. Tap "Use current location" to set a spot to roughly 1 km precision, or search for a town.

WHAT IT DOESN'T DO

Aerzeit doesn't model your home — it reports the outdoor conditions and leaves the judgment to you. Opening, sizing and timing the actual airing is yours. It reports public weather and environmental data (including air quality, pollen and UV) as a comfort tool, not medical advice; if a health condition makes any of those matter for you, follow your clinician's guidance.

PRIVATE BY DESIGN

• Empty Privacy Manifest. The app calls none of Apple's required-reason APIs.
• Minimal data. To fetch a forecast, the app sends a roughly 3 km grid cell to a server in the EU — no account, no identifiers, no raw GPS, no history. Your temperature range and all your filter settings stay on your device. The data export (Settings → Export my data) shows exactly what's held — it's all on your phone.
• No accounts. No analytics. No tracking. No advertising. No third-party SDKs beyond a small geospatial math library.

MADE INDEPENDENTLY

Aerzeit is built and published by Samuel Harrold, based in Indianapolis, Indiana, USA. Cultural reference: Stoßlüften — the German habit of a short, brisk airing-out — adapted for anywhere the weather gives you a window: between the humidity, the rain and the AC season, the trick is timing it right.

Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/