Our devices are shipped with built-in temperature sensors and that can "estimate" room temperature using an algorithm that runs on the device.
The learning period to estimate the room temperature usually takes between 3 to 5 HVAC cycles that have at least 2 hours of time distance between them. In extreme cold or hot weather, since the system is working for longer periods than usual and short intervals between them, the learning may take longer. During this time, the device will function fully as expected however, the users will not be able to see the room temperature until the learning period is finished.
Although this is not the most accurate and practical approach in some cases, it works perfectly for good majority of our users.
As part of our plans, we are working to integrate with standalone ecobee, Nest and 3rd party temperature sensors that can be placed anywhere in the rooms for better accuracy and also to avoid long learning times that some of our customers are experiencing.
* Please kindly note that any power outage and device reset will cause the learning process to re-start over again so do not reset the device and let the device continue its normal operation. As mentioned, during this time you will be able to use all the features of the app except room temperature.