ThermoLog

ThermoLog is a fully offline tool for testing and comparing the insulation performance of your thermos bottles. No internet required—all your data stays private on your device.

Add your bottles with names, brands, capacities, and photos. To run a test, simply record the initial water temperature, the ambient temperature, and then log temperature readings at different time points—after 1 hour, 3 hours, 6 hours, or any custom intervals you choose. The app automatically calculates the temperature drop and the overall heat retention rate for each test. A built‑in line chart visualizes the cooling curve, showing exactly how well a bottle held its temperature over time.

You can compare two bottles side by side by overlaying their cooling curves from selected tests. The stats screen gives you each bottle’s best and average retention rates, along with a trend chart of recent tests, so you can see if a bottle’s performance is declining.

Everything is organized in a clean, card‑based interface with a subtle textured background. ThermoLog never needs an internet connection, never asks for an account, and never collects any data. There are no ads and no in‑app purchases. It’s a simple, focused notebook for anyone who wants to know which thermos really keeps drinks hot the longest.