I need to wire a new house for ceiling fans. We want two fans to run off the same wiring, with switches on either side of the house....back door and front door. Do I need to run power to both switches, or will one side power both?

 

There are many ways to do this. The best way for you depends on the topology of your house.

Do I understand you right that you want two switches controlling two fans, and that flipping either switch will turn on and off both fans? Will the fans have a light kit and if so do you want separate switches for the lights?

If "=" represents a 14/3 cable, and "-" represents a 14/2 cable, then the main two options are:[list=1][*]Power-S1=S2-F1-F2.[*]Power-S1=F1=S2, and F1-F2.[/list=1]Based on what you said, the second option may be better for you. This wiring only gets you one switch for the fans' motors. You'd need more if you want a separate switch for a light on each fan.

You might also consider remote controls. There are pros and cons to them, but most fans these days seem to be sold with them already included.