Microwave Motion Sensors: What They Are and Why You Need One
When it comes to keeping your house safe, motion sensors are a must. Most people think of the little PIR (passive infrared) units that sit on ceilings, but there’s another option that often gets overlooked – microwave sensors. They send out low‑power radio waves and listen for changes, which lets them spot movement even through glass or thin walls.
That might sound like something out of a spy movie, but the technology is simple, cheap, and reliable. In the UK market of 2025, you’ll find several dual‑tech devices that combine PIR and microwave to give you the best of both worlds. If you’re setting up a new alarm system or upgrading an old one, understanding microwave sensors can save you money and headaches.
How Microwave Sensors Differ From PIR
PIR sensors detect heat. When a warm body moves in front of the sensor, the temperature change triggers an alarm. They work great in rooms where the temperature stays steady, but they can miss a fast‑moving intruder or be fooled by drafts.
Microwave sensors, on the other hand, use Doppler radar. They emit a short burst of microwaves and measure the echo. If something moves, the echo changes and the sensor reacts. This means they can sense motion behind a glass door, through thin partitions, and even in bright sunlight where PIR sometimes struggles.
The trade‑off is a slightly higher chance of false alarms from pets or fans, but modern units let you adjust sensitivity and filter out small objects. That flexibility makes them a solid pick for garages, basements, and larger open‑plan areas.
Choosing the Right Sensor for Your Home
First, think about where you need coverage. If you’re protecting a front porch with a glass front door, a microwave or dual‑tech sensor will catch someone standing just outside. For a bedroom or living room, a PIR unit is usually enough and cheaper.
Second, consider integration with your existing alarm. Most UK‑based systems – including ADT, SimpliSafe alternatives, and local providers – support standard zones, so you can mix and match. Look for models that list “dual‑technology” or “PIR + microwave” in the specs. Those give you redundancy: if one method fails, the other still catches motion.
Third, check power requirements. Microwave sensors draw a bit more current, so they’re best placed on circuits that can handle the load. If you’re wiring a new panel, ask your installer to allocate a dedicated line for sensors that need extra power.
Finally, test before you lock the system down. Walk around each sensor’s range, open and close doors, and see how quickly the alarm triggers. Adjust the sensitivity knob until you get reliable detection without constant beeps from your cat.
In short, microwave motion sensors fill the gaps that PIR leaves open. By pairing them with the right alarm panel and fine‑tuning the settings, you’ll have a layered defence that’s harder for a burglar to bypass. Whether you’re a DIY homeowner or working with a professional security company, adding a microwave or dual‑tech sensor can boost your peace of mind without breaking the bank.
