Is there a good Android app to check if my air conditioner or heater is working properly?

Room Temperature Thermometer is a practical utility app designed to provide immediate feedback on ambient indoor conditions. For users troubleshooting an air conditioner or heater, its primary function is to deliver a quick, sensor-based temperature reading of the room. The app interfaces with the device's built-in ambient temperature sensor, displaying the result in a clear, large-font interface. A key feature for this use case is the ability to track slight changes over time, helping to confirm whether a newly adjusted thermostat is actually affecting the room's climate. Reviews indicate users frequently employ it for this exact scenario, comparing the app's reading to their HVAC system's display to check for discrepancies.

However, the app's effectiveness is inherently tied to the hardware. Not all Android devices possess a dedicated ambient temperature sensor; on models without one, the app may provide an estimated reading based on other data, which can be less reliable. The interface is simple and ad-supported, which keeps it accessible but may include occasional banner ads. While it won't replace a professional-grade thermometer for precision tasks, for a quick diagnostic check on home climate systems, it serves its purpose well. The option to calibrate the reading with a known offset can help improve accuracy if a baseline discrepancy is discovered.