How to add presence detection to every room

Presence detection is one of the most useful automations you can build, but it requires more than just a motion sensor in each room. True presence detection tells your system not just that something moved, but that a person is actually in the space. Here’s how to approach room-by-room presence detection with local control.

Why Room Presence Matters

The difference between motion detection and presence detection is the difference between a light that turns off when you’re still and one that stays on while you read in bed. Basic motion sensors only trigger on movement, so they fail in exactly the situations where you need them most—sitting still, sleeping, or working at a desk.

True room presence detection keeps your automations running smoothly without manual overrides. You can auto-off lights when everyone leaves a room, maintain climate control while someone’s home, or trigger ventilation based on occupancy rather than arbitrary schedules.

Sensor Types and Tradeoffs

Different sensor technologies give you different capabilities, and each has real limitations worth understanding.

PIR (Passive Infrared) motion sensors are the cheapest option and work well for basic occupancy. The Philips Hue motion sensor is reliable if you already have Hue, but it requires the Philips Hue Bridge and won’t report no-motion for 10 minutes after detecting activity. The Aqara Motion Sensor P2 uses Matter over Thread, works locally with Home Assistant, and integrates cleanly without any cloud dependencies.

Millimeter-wave (mmWave) sensors detect micro-movements like breathing, making them far better for true presence detection. The Aqara FP2 is the standout option here—it detects presence even when completely still, supports multiple detection zones per room, and runs locally. The Everything Presence One is purpose-built for Home Assistant with excellent community integration. These sensors do cost more than PIR alternatives, but the reliability gains are substantial if you want automation that actually works.

Door and window sensors are a simpler approach—install them on interior doors and you can infer room occupancy based on which doors are open. The Aqara Door Window Sensor P2 is Matter-compatible and reliable. This works best as a complement to motion sensors rather than a standalone solution, since you can’t tell if someone’s still in a room with the door closed.

Smart thermostats with room sensors like the Ecobee Premium or Google Nest Thermostat can contribute occupancy data, though they’re primarily climate devices. The Ecobee’s remote sensors detect motion and can feed presence data to Home Assistant.

Choosing Sensors by Room Type

For bedrooms and offices where people sit still, mmWave is essential. PIR sensors will constantly time out and leave you in the dark. The Aqara FP1E is a more affordable fp2 variant that still handles static presence well.

For bathrooms and kitchens, PIR is usually sufficient since people are typically moving in these spaces. The Eve Motion works well with Home Assistant via Thread, or you can use Shelly Plus 1 with a basic PIR for a budget approach.

For living areas where you might be watching TV or reading, mmWave again proves worthwhile. Consider the Everything Presence Lite if you want a dedicated presence sensor without the full feature set of the One.

For garages, basements, or utility rooms, door sensors plus basic motion is usually enough. These spaces have lower automation needs and simpler detection requirements.

Implementation Tips

Whatever sensors you choose, a few practical notes will save you headaches:

Use occupancy holds. Set a delay before declaring a room empty—10 minutes is a good starting point. This prevents lights from cutting out when you sit still to check your phone.

Combine sensor types for better reliability. Use motion as the trigger, then mmWave or door sensors to confirm presence. The Aqara FP2 supports this natively with its motion + presence detection modes.

Mind the installation angle. mmWave sensors need proper placement—ceiling mount typically works best, and they can struggle around air vents or fans that cause false positives.

Consider power options. Most mmWave sensors need constant power (Aqara FP2 includes a USB-C power option), while battery-powered PIR sensors are easier to place but require occasional battery changes.

Bottom line

For most rooms, the Aqara FP2 is the best balance of capability and local control. Pair it with Aqara Door Window Sensor P2 for door-based confirmation, and you have reliable presence detection that works entirely offline. If budget is tight, use Aqara Motion Sensor P2 with appropriate occupancy delays—it won’t match mmWave reliability, but it’ll work for basic automation needs.

The real insight: don’t try to solve every room the same way. Bedrooms need mmWave. Hallways might only need a door sensor. Utility rooms might not need presence at all. Build sensor coverage to match your actual automation needs, not an idealized perfect system.