The setting is obviously based around a future world with an unprecedented level of technological sophistication. But your question also points towards the mood that is created by the description of the setting. It is clear that the description Bradbury uses creates a desolate, lonely mood, as we are presented with a world in which humans have been made extinct. Consider the following examples:
The morning house lay empty. The clock ticked on, repeating and repeating its sounds into the emptiness. Seven-nine, breakfast time, seven-nine!
Notice how the repetition of "empty" and "emptiness" serve to create the desolate mood of a world without humans.
The sun came out from behind the rain. The house stood alone in a city of rubble and ashes. This was the one house left standing. At night the ruined city gave off a radioactive glow which could be seen for miles.
Here, the description of the one house left standing in a city of "rubble and ashes" again reinforces that impression of desolation and destruction. Note how the "radioactive glow" creates an eerie impression of danger.
This mood continues to be sustained and developed throughout the story as we are witnesses to the normal daily routine of this household - but without humans. Again and again the high level of technological sophistication we are presented with emphasises one of the key themes of the story - the irony that man has reached such scientific heights but has also managed to make itself extinct through those same advances.