Over the air convenience
A real pain point when developing sensor nodes that are scattered around a building (or a country or the world!) is the updating part. How do you get new firmware onto the devices?
The cell phone manufacturers were early to investigate the options, but from my days in that industry I know first-hand how challenging it was to send new firmware to tens or hundreds of thousands of devices. Lot’s have happened since, today a system update for tens of millions of Android or IOS devices is no big deal, you just make sure your phone is plugged into power before starting the upgrade. Leave it overnight, and next morning you have the latest (and hopefully greatest) version installed.
Looking specifically at the ESP8266, it does have drawbacks in terms of power consumption (it’s hard to get the power consumption down for a device that needs 3-4 seconds to wake up from sleep, connecting to a wifi network and send its sensor readings – but improvements are possible). On the other hand, its wifi connectivity means Over The Air (OTA) updating is possible.
Having a bunch of ESP8266’s lying around, I looked into the options for doing OTA on ESP8266.