If you are in average home, you can see not only your own WiFi, but that of your neighbours also. This is exactly the same.
Things to consider:
1. Use different channels in the same frequency band (2.4 or 5 Ghz) or different bands to minimize interference.
2. You'll have to choose between having 2 Internet-connections (like you and your neighbour) or connecting both WiFi-networks to the same Internet-connection. Seen from the congestion point-of-view the first is preferable (not WiFi congestion, but connection congestion).