Empty room sits at 19°C. Someone walks in — temperature rises to 21°C in 5 minutes. Leaves — back down. ~25% heating saving.
Trigger
Presence sensor (mmWave radar) detects change
Action
TRV setpoint 21°C while presence active · 19°C while room empty > 10 min
Devices needed
Why it helps
In many Moldovan flats and houses every room is heated the same, even the ones where no one sits for hours — the bedroom by day, the office at night, the guest room almost always. This scenario keeps empty rooms at an economical background temperature (19°C) and brings them to comfort (21°C) only when you are actually there, read correctly by a radar that also sees people sitting still. In the cold season, when heating is the bulk of the bill, that means comfort where you are and less heat wasted on empty rooms — without touching a manual thermostat.
How it works
The trigger is the Zigbee mmWave radar presence sensor placed in each room: unlike a classic PIR sensor, radar detects people who sit still, so real occupancy is read correctly. When the radar reports "occupied", the logic on the hub sends the TRV (the thermostatic head on the radiator) a 21°C setpoint command, and the room reaches comfort within a few minutes. When the radar no longer sees anyone, a timer starts: if the room stays empty for more than 10 minutes, the setpoint drops back to the 19°C background. The 10-minute threshold stops the temperature from swinging when you just pass through or step out briefly, and each room runs its own loop, independent of the rest of the house.
CasaSmart configures all of this logic locally, on a central hub (usually Home Assistant). The mmWave sensors and TRV heads talk to the hub directly over Zigbee, with no dependence on a cloud server — the core automation keeps working locally even if the internet drops. We choose the radar placement to cover the seating area without false triggers from the hallway, tune sensitivity and delays, calibrate the TRV's offset against the room's real temperature, and bind each sensor to the correct radiator. In the end you get clear scenes (Home / Away / Night) and control from one app, while the 19°C and 21°C thresholds are adjusted to your preference.
Setup steps
Together we decide which rooms join the scenario and check that each radiator has a valve where a Zigbee TRV head can be fitted. We note where you usually sit (desk, bed, sofa) to place the radar correctly.
We mount one Zigbee mmWave sensor per room aimed at the seating area, and replace the old valve with a Zigbee TRV on each radiator. Everything connects to the central hub over Zigbee.
We calibrate each mmWave sensor's sensitivity and range so it catches a still person but ignores hallway movement or curtains. We set the "room empty" delay to 10 minutes.
We program the logic on the hub: 21°C on presence, 19°C after 10 minutes empty, each room separately. We add Away and Night scenes and bring control into a single app.
We test every room under real conditions, fine-tune the thresholds to your comfort, and show you how to change temperatures or temporarily pause the scenario from the app.
Practical tips
FAQ
A classic PIR sensor only sees movement, so it would leave you cold while you sit still at a desk or read on the sofa. The mmWave radar detects real presence, including a person sitting quietly, so the comfort temperature stays on as long as you are actually in the room.
Yes. The logic runs locally on the central hub (usually Home Assistant), and the sensors and TRV heads communicate over Zigbee, not the cloud. The core automation — presence, the 21°C/19°C thresholds — keeps working locally even without internet; only remote access and notifications need a connection.
Usually yes, if the radiator has a valve where a Zigbee TRV head can be screwed on — that covers most water radiators in flats. During the survey we check the thread and the valve's condition; if needed, we recommend replacing the valve. Systems with no radiator valve (some underfloor heating, for example) need a different approach, which we discuss on site.
Savings depend on the home: insulation, how many rooms sit empty, and how big the gap is between 19°C and 21°C. The principle is simple — you stop heating empty rooms to comfort, and over a season that shows on the bill. We can start with a single room so you see the effect before extending the scenario to the whole house.
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