The real fork is specialized function versus pir motion sensors
mmWave presence sensors win when they can detect stationary occupancy where a PIR sensor would time out and that function removes a known recurring problem. PIR motion sensors win when they reach the same outcome with fewer dependencies, less maintenance, a more understandable failure mode, or a cleaner return path.
Normalize detection zones and range and wall, ceiling, or corner geometry
Compare both paths across the same fixture, circuit, controller ecosystem, radio path, owner account, and manual fallback, with every required dependency included. A complete mmwave presence sensors package should not be compared with an incomplete alternative, and a retailer headline should not replace product-level compatibility evidence.
Use false presence through thin materials and hub, power, and automation latency as tie-breakers
In a mmwave presence sensors comparison, false presence through thin materials and hub, power, and automation latency reveal the friction that appears after an attractive demo. Choose the path that can be installed, used, cleaned, updated, and recovered by the people who will actually own it. Prefer the simpler failure mode when performance is otherwise close.
Compare ownership, not only purchase price
mmWave presence sensors bring an ownership path of zone retuning, firmware, permanent power, changed furniture, and false triggers from fans, curtains, pets, or activity beyond walls. Price that against the maintenance and replacement work of pir motion sensors over one normal year. Include the value of time and the cost of losing the service while a proprietary part, account, or repair is unavailable.
Make the choice reversible
Use this test path before the return window closes: mount temporarily, observe raw detection for several days, exclude fans and adjacent rooms, then use presence in noncritical automations. Preserve the old setup and packaging until the product survives normal use. Choose the alternative immediately when the room geometry cannot isolate the target area or the automation has safety consequences when presence is wrong.