Sigfox, Wifi, or else, my recommendation is the same : when you have nothing to say, do nothing :)

In most "connected" devices, you don't need to keep an established connection which will drain the battery fast.

This is why idle consumption is key, as it will often be the state of the solution 99.x% of the time

Simply turn the communication module on when you need it.

Then the difference between solutions consumption-wise will be on time needed to establish connection if any, time & power to send your data.