Kūki

How fresh is the air in this room?

CO₂, temperature, humidity and PM2.5, room by room. Drawn as an ensō, the single brush-stroke circle of Zen calligraphy.

Coming soon to theApp Store

iPhone · iPad · MacWorks with IKEA ALPSTUGA via Apple Home

Four Kūki screens: Now showing 631 ppm CO₂ and clear air in the kitchen, History comparing rooms over 24 hours, the same Now screen at night, and the dim Station Mode.

円相Clear air is a short stroke. Stale air closes the circle.

CO₂ is the one thing that matters most indoors. Kūki shows it as a brush circle and tells you, plainly, whether to open a window.

澄 Clear air

Like outside. Nothing to do.
和 Fine

Comfortable. Air it out soon.
淀 Getting stale

Open a window for a few minutes.
濁 Stuffy

Ventilate now — focus and sleep suffer.

繋Works with IKEA ALPSTUGA via Apple Home

Add the sensor to the Home app once. Kūki reads it from there. No IKEA hub, no cloud, no account.

IKEA ALPSTUGAAir-quality sensor · Matter
Thread
Apple HomeHomePod or Apple TV as Home hub
HomeKit
KūkiiPhone · iPad · Mac

Other Apple Home sensors that report CO₂, PM2.5 or air quality work too. Which sensors work?

常On the Mac, it records around the clock.

Kūki lives in the menu bar. Window open or closed, it keeps listening to your sensor and writes the history, 24/7.

Show CO₂, temperature, humidity or PM2.5 next to the clock.
A small mark appears only when the air needs opening up.
Move Sensor To, Station Mode and Open at Login from the menu.

Kūki on the Mac in dark mode: 623 ppm CO₂ in the living room, with temperature, humidity, PM2.5 and the last three hours.

書出Ask Claude or ChatGPT about your air.

Export a Markdown brief made to paste into a chat: context, a summary per room, and the data averaged so it fits.

Or take every sample at full resolution as CSV, for Numbers, Excel or Google Sheets.

The Export screen: a Markdown file for Claude or ChatGPT, and a CSV spreadsheet, for the last 24 hours, 7 days, 30 days or all.

Everything, quietly.

今
Now
CO₂ in the ensō with plain advice, plus temperature, humidity, PM2.5 and the last three hours.
居間
Places
Tell Kūki which room the sensor is in. Carry it around and it keeps a history for each room.
記録
History
3 hours to 30 days. One-line takeaways, averages, peaks and time over your limit, per room.
一目
Widgets & Live Activity
Home Screen, Lock Screen, Dynamic Island and StandBy. They fade honestly when a reading gets old.
雲
iCloud sync
Optional. History, rooms and the latest reading move between your devices through your private iCloud.
風鈴
Fūrin alert
A soft wind-bell and a notification when CO₂ crosses your limit. Once per stuffy spell, not every minute.
灯
Station Mode
A dim, always-awake screen for a spare iPhone or iPad on a charger, so it keeps recording.
常
Mac menu bar
Runs from the menu bar and records 24/7, with your chosen value next to the clock.
書出
AI-ready export
A Markdown brief for Claude or ChatGPT, or a full-resolution CSV.

On iPhone and iPad, Kūki records while it’s open. Apple Home only updates the app in front. For a full day of data, leave a spare device in Station Mode, or let your Mac record around the clock and turn on iCloud sync.