You'll have to make sure your wifi is turned on if you want the possibility of using wifi when available. As far as using wifi for calls, not unless you're doing it through some kind of voip. Likely that it'll default all regularly placed calls through the 3g network.

 

Which will cause the battery to drain faster? While I am sitting at home I would prefer to have the wifi turned on...but not if it eats the battery much faster.

Anyone know for sure?

 

I don't know if this is the case for everyone else, but I have found that my battery drains MUCH faster when my WIFI is turned on. My battery stays charged way longer when I am only using 3G and have WIFI off.

 

WiFi will use less juice than 3g. But if you're away from WiFi, turn it off cuz the WiFi radio will drain for nothing. Luckily both Android and HTC have WiFi widgets to plop on your home screen to make turning off & on easy.

 

I don't know if mine has a problem then or what, because even when I'm in my living room right next to my Wireless router with full strength, my phone still uses way more battery with my WIFI on then if I am just using 3G