I send the data from my esp8266's directly to the internet if needed (to thingspeak cloud) and also to my local qnap NAS hosting a postgres database. I'm removing the thingspeak calls progressevely to postgres so I don't rely on cloud services anymore. works really nice. each 8266 holds 1 to 5 sensors or actuator in the house. running fans, hvac, burner, or measuring temperatures or humidity.
enough for a modern house without polluting the internet and other's expensive servers.
and I use simple arduino sketches to run all this. with OverTheAir updates of course.