[lfjj]

I always switch to 2G (data off) when I am not doing anything with the phone. Does 2G drain less battery than 3G in standby/idle?

[JammyGitz]

Yes 2G is better for battery because I think it runs on a lower frequency

[Philippe Maes]

The difference is very noticable when you have very bad 3G reception (1 bar). My phone would drain 8%/hour when idle, so I always switch to 2G then.

[eric12341]

Yea unless you have poor 3G/4G reception where you'll be leaving the phone idle it's best to switch to 2G otherwise no difference. In fact in areas where 2G reception is even with 3G/4G reception then battery consumption with data usage on 2G would be greater because the modem is working harder to transmit data.