A think you need to know what the wattage is and what your suppliers charges per killowatthour. If you have the cameras allready and a smart metre you can test it
Does anyone use that type of CCTV these days, Hymie? Mine doesn't use a DVR - it records to the cloud, and is motion activated so isn't running 24/7.
The cost of running the router is discounted from my calculations because I would have it for the internet regardless.
There are thousands of them available on ebay – I would not trust the cloud to be a reliable connection/secure storage medium. Depending on recording image quality/frame rate, a four camera system data storage for a month will likely exceed 1TB (how much will this cost).
My system is very secure, reliable and best of all I can access the cameras and recordings wherever I am. Picture quality is very good day and night. It’s been up and running for four or five years without problem. I can download recordings if I choose to. A relative of mine had his system connected to a pvr and the burglars took that as well.
Obviously if you have a DVR ccty system, the DVR must be in a secure location.
Most have the facility to be connected to a router allowing remote access.
I can't tell you exactly how much it cost but I can tell you a way to find out how much it cost.
Multiply the wattage by the average number of hours the device is used per day. Let's say you use a 100-watt electric fan for 10 hours per day. Multiplying 100 watts by 10 hours will result in 1,000 watt-hours—that's how much your electric fan consumes in a day. Convert watt-hours to kilowatts.
If you have separate plugs on the system, plug them all into a 4 or 6 way mains extension block and then plug that into the monitor before plugging the device into your wall socket.