I looked at my system. I have a Unifi AP-AC-Lite Access Point for all of my WiFi traffic in my home, and thus have all of these fancy statistics that I can look up.
For my Iro2, it connected with a 2.4 GHz signal, at 57% of full strength, running a TX rate of 65 Mbps and an RX rate of 19.5 Mbps.
I turned on statistics collection for a couple of hours. I see that 16.8 kB were downloaded, and 47.2 kB were uploaded.
My Iro2 is ranked last in the list of WiFi connections to my AP in terms of bytes downloaded (or bytes uploaded) during the couple of hours.. Each of my hot water heaters (also connected to the Net) transmit and receive more than my Iro2 does.