India, Nov. 8 -- A smart home is easiest to admire when everything works. Its engineering becomes far more interesting when something does not. The broadband link fails, but local Wi-Fi remains alive. Power returns after an outage, yet the router, automation controller, and connected devices recover at different speeds. Someone turns off a familiar wall switch and cuts power to the smart bulb behind it. A robot vacuum gathers dust on an optical sensor. A purifier suddenly runs harder while dinner is being cooked.

Each incident exposes a dependency that was easy to ignore during installation. That is what makes the Indian home such a useful stress test for smart-home technology. Dust, cooking emissions, reinforced walls, existing electric...