Sigrile: Room Heat

Sigrile turns a phone left still by the bed into an evidence-aware record of how a room releases retained heat overnight.

The battery sensor is not the room. It responds slowly and includes heat made by the phone itself. Sigrile identifies that delay and the effect of idle, charging and screen activity, then reconstructs the finished night with a thermal model. The result is one plain sentence above a night band whose thickness shows uncertainty.

Each morning, see whether the room released heat before dawn, the estimated minimum when an absolute anchor has been earned, and the evidence behind the answer. If movement, screen use, changing power, missing samples or uncertainty make the night unreliable, Sigrile refuses the result in plain words instead of presenting a confident number.

Add an optional town or city for an evening forecast. Sigrile stores only coordinates rounded to 0.25 degrees and uses the outdoor curve to estimate the likely overnight range and the time when cooler outside air may begin to help. It never asks for Android location access or an address.

Core overnight sampling, filtering and room inference work on the phone without an account or network. Samples use their actual timestamps, tolerate normal irregular spacing, and remain in the private app database.

With consent, add one trusted person using a short-lived code. They see one morning sentence and nothing else. Either installation can end sharing silently. A structured cooler-room offer can be sent only after two independent eligible nights; it expires, has no free-text message or public home directory, and can be declined or reported.

Anonymous locality comparison is separately opt-in. An eligible night contributes only a coarse four-character geohash cell, minimum and hour, crossover, uncertainty, and broad building type. One-use blind-signed tokens separate the summary from the installation. Results stay hidden until at least five independent rooms contribute.

Sigrile is an uncertainty-aware household estimate, not a certified thermometer or alarm. Its 24 °C night context is attributed in the app to published World Health Organization heat-wave advice; Sigrile does not make a personal claim from that threshold.

Accessibility includes clear contrast, scalable text, Celsius or Fahrenheit, and a reduced-motion thermal band.