Alarm Sensor Types and How to Choose Them
Different spots in your home need different sensor types — here's how to pick the right one and place it so your alarm doesn't cry wolf.
How to choose sensors, step by step
Map your zones first
Split the property into perimeter, interior and any 24h zone (like a safe) before you think about sensors — the list follows the zones, not the other way round.
Match sensor type to location
PIR motion detectors suit open interior spaces, magnetic contacts suit doors and windows, glass-break sensors suit rooms with large windows, vibration sensors suit doors and safes.
Place it correctly
Keep PIRs off pet routes and away from heaters, avoid draughty windows and direct sunlight — that alone prevents most false alarms.
Confirm with a specialist
Always check the exact model, sensitivity range and install details with a shop or a certified installer — it differs for every location.
The core sensor types
5 basic sensor types
Each one has its own job — none of them is a one-size-fits-all answer for the whole house.
PIR motion detector
Senses body-heat movement, great for open interior spaces and hallways.
Magnetic door/window contact
Detects an opening directly — the basic building block for any perimeter entry point.
Glass-break sensor
Listens for the sound of breaking glass, useful for rooms where a contact alone isn't enough.
Vibration/shock sensor
Picks up a physical hit on a door, wall or safe before it's actually broken through.
Outdoor beams and curtain sensors
Infrared beam pairs or outdoor PIRs catch an intruder before they even reach the building — good for fence lines and approach paths.
What a solid sensor plan covers
Work through these before you go shopping.
- {'t': 'Zones and partitions', 'd': "A clear picture of what needs protecting always (a 24h zone) versus only while you're away."}
- {'t': 'A sensor type per location', 'd': 'Not one type everywhere — a deliberate choice based on the room and the risk.'}
- {'t': 'Placement that avoids false alarms', 'd': 'Distance from heaters, pet routes and draughty windows checked at the planning stage.'}
- {'t': 'Wired vs wireless, weighed honestly', 'd': "Wired suits a new build, wireless (technologies like DSC PowerG, for example) suits a finished room you don't want to chase walls in."}
- {'t': 'Questions to bring to the shop or installer', 'd': 'A list of what to ask about sensitivity, supervision and install work, so the choice is deliberate, not guesswork.'}
Frequently asked questions
What sensor type do I actually need?
It depends on the location — PIR for open rooms, magnetic contacts for doors and windows, glass-break for rooms with large windows. Talk it through in the shop for your exact case.
Why does my motion sensor keep false-alarming?
Usually it's placement — aimed at a pet route, a heater, or a window that moves in the draught. Reposition or re-aim it first.
Are wireless sensors as reliable as wired ones?
It's a tradeoff, not a clear winner — wireless suits a retrofit without chasing walls, but relies on batteries and an RF link; good systems supervise every sensor and flag it if it goes quiet.
How long does a wireless sensor battery last?
That depends entirely on the model and how it's used — always check the manufacturer's datasheet rather than a generic number.
Do I need a specific EN 50131 grade?
That depends on a risk assessment and often the insurer's requirements — a certified installer should confirm it, not a guide page.
Want to talk through your sensor plan?
Book a consultation or browse sensor options in the shop — we'll help you ask the right questions, no sales pressure.