Each camera will have a 12V DC adapter that plugs into a 120 volt AC wall outlet. How the power is run to each unit will need to be given some thought. This is not as difficult a hurdle though as having to run wires through walls. Summary Using a wireless security camera system with a DVR is a good option when adding wires is not an option. Keep in mind wireless doesn’t perform well in some cases and degrades with distance and barriers. One way to get a rough idea how well a system will work is to use a smartphone or tablet to stream YouTube videos and walk around to spots the camera will be located at. While there is different WiFi technology being used for each device it can give a general idea how well wireless will stream to a location. While WiFi cameras and DVRs have come a long way from the older early days they still can at times lag a bit. As long as you are aware of it limitations than you should have limited problems setting up and using a system. Always be sure to read the reviews on Amazon or elsewhere to be sure a system is a good fit for you. We all want to feel safe and secure at home.