Sixteen channels is the professional threshold: a medium-sized business, a building, a warehouse, or a site across two buildings.
What changes compared to 8 channels
Beyond the number of cameras, two things matter. First, the recording bandwidth: a 16-channel NVR accepts a higher total bitrate, allowing 8MP cameras to run smoothly without compromise. Second, the two drive bays, present on most models: they double the capacity, thus the retention duration.
Sizing the storage
Sixteen 4MP cameras continuously consume around 8 TB per week. Over thirty days, we're talking about 24 TB—either two 12 TB drives or switching to recording on detection. This calculation should be done before ordering, not after.
Networking becomes an issue
With sixteen cameras, the switch and cabling are no longer neutral. Plan for Cat 6, check the total PoE budget, and don't forget the 100-meter limit per Ethernet segment—beyond that, an intermediate switch or fiber is needed.
UPS
For an installation of this size, a UPS is no longer an option. A power outage during writing can corrupt the file system and result in the loss of several days of recording.