Door & Window Sensors

The best all-round pick for most homes. It is the smallest sensor here, comes in three finishes so it actually disappears against a frame, and manages five years on a single common coin cell — while also reporting tilt and temperature, which most rivals at twice the price do not.

The trade-off is Bluetooth: it does not join a mesh, so it needs a hub or Bluetooth-capable device within range. In a normal house that is a non-issue; in a large or thick-walled one, check coverage before buying twelve.

If battery maintenance is what you dread, this is the answer. Nine years sounds implausible until you understand that battery-powered Zigbee devices spend almost all their time in deep sleep — and frient uses AAA cells rather than a coin cell, giving it far more capacity to work with.

The vibration sensor makes it a better security device than a plain contact, because it detects a window being forced while still closed. The shape is the compromise: long, thin and white, which is invisible on white uPVC and obvious on oak.

The choice when the sensor must not be visible. At 3 mm thick it follows the line of the frame and genuinely disappears — which is why architects and interior designers specify it. It is also properly weatherproof and works to −30 °C, so it covers garden gates, sheds and outbuildings.

The ten-year battery is sealed. When it eventually dies, replacing it requires soldering, so in practice treat this as a ten-year consumable. At around €40 that is €4 a year, which is reasonable for something invisible.

The future-proof pick. Matter over Thread means it pairs directly with a Thread-capable hub and will keep working as ecosystems change. The larger CR123A cell buys three years of life, and the supplied slim magnet makes it usable on metal surfaces where an adhesive pad alone would struggle.

Its one flaw is length — 77 mm is a lot of sensor. Measure your narrowest frame first. Worth noting that Aqara’s previous-generation Zigbee sensor remains one of the best small contacts ever made, and is cheaper if you do not need Thread.

This one sits inside a hole drilled in the frame, so once the door is closed there is nothing to see at all. If a visible sensor is unacceptable and 3 mm is still too much, this is the option — at the cost of a drill and a careful afternoon. Aeotec also makes a Zigbee multipurpose version that adds vibration, tilt and temperature.

Fibaro solves the visibility problem differently: rather than making the sensor small, they make it available in seven colours so it matches the frame. Match it correctly and the size stops mattering. Build quality and Z-Wave stability are both excellent, and the built-in temperature sensor doubles its usefulness.

The security-focused Z-Wave pick. S2 encryption and SmartStart pairing make it a good fit if the point of the exercise is genuinely protecting the house rather than triggering lights. Zooz sells a weatherproof case for outdoor use. The one-year battery life is the weak point, so budget for annual changes.

Beautifully made and completely reliable, with a status indicator built into the button in the middle. It is also the least featured sensor here at the highest price, with no temperature, tilt, vibration or tamper detection. Buy it if you already run Hue and want everything in one app; otherwise the value is hard to justify.