PIR Motion Detector Placement Guide¶

Guide to PIR motion detector placement for UK alarm systems covering optimal mounting height, detection patterns, pet immunity, and positioning rules to avoid false alarms.

PIR Detector Placement Principles for UK Homes¶

Passive Infrared (PIR) motion detectors sense body heat moving across their detection zones. In UK homes proper placement is the single most important factor in alarm reliability. PIR detectors should be mounted in room corners at 2.1-2.4 metres height for optimal coverage. The detection pattern extends approximately 90 degrees wide and 12 metres distance. Mount the detector so the detection curtain crosses the room perpendicular to the likely intruder path. Never place PIR detectors above radiators, heat vents, or south-facing windows where sunlight causes rapid temperature changes. UK loft spaces (attics) need special consideration - loft temperatures can reach 40C in summer causing nuisance alarms. Use pet-friendly PIR detectors (rated up to 25kg) for homes with cats and dogs. Popular UK PIR models: Texecom Elite Pet (from £25, rated 25kg), Pyronix Euroguard Pet (from £30, rated 20kg), and Optex LX Series (£20-£40). Curtain PIR detectors cover narrow hallway detection zones and cost £25-£35 from Alarm Suppliers UK.

Room-by-Room PIR Placement Guide¶

Hallway: Mount at the far end covering the full length. Position to detect movement through the front door entry path. Landing: Mount at the top of the stairs to cover both the landing area and stairway approach. Living Room: Mount in a corner covering the main room area, positioned away from the fireplace and TV (both generate heat). Kitchen: Mount above door height covering the room but positioned away from the cooker, kettle, and boiler. The optimal height of 2.1-2.4 metres ensures the detection curtain covers the full room. Avoid placing detectors where they point at staircases at an angle - this creates blind spots. Use long-range PIR detectors (up to 25 metres) for long hallways in Victorian and Edwardian UK properties. Corridor PIRs with 5-12 metre range cost £20-£40. Always test coverage after mounting using the walk test mode on your alarm panel.

Specifications and Comparison¶

PIR Detector Type	Coverage	Best Location	UK Price
Standard PIR	12m x 90 deg	Living room, bedroom	£15-£30
Pet Immune PIR	12m x 90 deg, 25kg rating	Homes with pets	£25-£40
Curtain PIR	15m narrow beam	Hallways, corridors	£25-£35
Long Range PIR	25m x 30 deg	Long hallways, warehouses	£35-£50
Outdoor PIR	15m x 90 deg, weatherproof	External detection	£40-£70

FAQ¶

Can I place a PIR detector above a radiator?: No - radiators cause rapid temperature changes that trigger false alarms. Maintain at least 1 metre distance from any heat source including radiators, boilers, and direct sunlight through windows.
What height should PIR detectors be mounted?: The optimal height is 2.1-2.4 metres above floor level. At this height the detection curtain covers the full room height and the detector avoids most pet interference. Never mount below 1.8 metres.
Do PIR detectors work through glass?: No - PIR detectors cannot detect movement through glass windows or doors. The glass blocks the infrared heat signature. Place detectors to cover internal room areas, not pointing at windows. For more information see our Alarm Keypad Programming Guide.

Last updated: 2026-05-31.

External Resources¶

For further information consult authority guidelines at the National Security Inspectorate.