A PoE+ switch supplies more power per port than standard PoE, following the 802.3at standard. That headroom runs PTZ motors, heaters and blowers, or cameras with powerful infrared illuminators. Roughly 25 watts reach the device, against about 13 for standard PoE.
PoE+ is a power budget, not a speed upgrade. The data rate is unchanged; what changes is how much a single port can give.
Per-port and total budget
A switch may allow 30 watts on one port yet cap total output well below the sum of its ports. Add up every camera and heater, then compare with the switch’s total budget and power supply.
Heat and headroom
Powered devices draw most at startup, and heaters switch on in cold weather. Leave headroom, keep ventilation clear and put the switch on a UPS so cameras survive an outage with the recorder.