I want to add a second Roku3 in another room but the range of a RoKu3 remote covers the whole house. Can I have 2 RoKu3 units in one house without the remotes controlling the wrong RoKu ?

Less important, but the opposite question. Can 2 RoKu3 remotes be assigned to one RoKu ? (Like DishTV UHF remotes get "paired" to thier boxes in any combination to be separate or mirrored)

The remotes pair with their own Roku so they operate independently.

You can pair two remotes with one Roku but the earphone function only works one at a time.

^This.

C. Shawn Smith

You will have extra wifi interference however since they use a full channel (as opposed to BT which uses a fraction of a channel.) Many routers will detect this and go into neighbor friendly mode. If possible I'd put one or both on a different frequency from other devices. I've been told that the interference isn't as bad as the router thinks it is since little of that channel is actually used, too bad the routers don't take that into account.