SwitchBot
SwitchBot Meter Pro CO2
- Bluetooth
Verified September 2026
The affordable route to CO2 monitoring: a genuine NDIR sensor (Sensirion SCD40) plus temperature and humidity on a big desk display for around £60 — half the price of an Aranet4. Reviewers cross-checking it against calibrated meters report readings within about 5%, respectable for this price. The catch is Bluetooth: it only talks to whatever's nearby, so anywhere outside your HA host's BLE range needs an ESPHome proxy or USB Bluetooth adapter in the same room. Best sited in a bedroom or home office, where stale air affects sleep and focus — keep it on a desk away from doors and vents, not a draught. No SwitchBot hub required.
In Home Assistant
| Control | Type | What it does |
|---|---|---|
| CO2 | Sensor (ppm) | NDIR carbon dioxide reading |
| Temperature / Humidity | Sensor | Room conditions |
| Sync time | Button | Correct the onboard display's clock |
A confirmed HA bug had this specific model misidentified as a completely different SwitchBot product (a light strip), creating a light entity instead of sensors until fixed — worth an integration reload if readings don't appear after pairing. Because it's read over BLE, having the SwitchBot app open on a phone at the same time as HA's connection can cause timeouts from competing connections. There's also a sync-clock button entity worth automating on a daily schedule to keep the onboard display's time accurate through DST changes, something manual in the SwitchBot app otherwise.
Specs
- power
- 2x AA batteries (pre-installed, ~1 year) or USB-C
- display
- LCD, no backlight, large digits with comfort indicator
- requires
- HA Bluetooth adapter or ESPHome Bluetooth proxy in range
- co2 range
- 400-9999 ppm
- dimensions
- 92 x 79 x 25 mm, 154g
- sensor type
- CO2 (NDIR, Sensirion SCD40), temperature, humidity
- co2 accuracy
- ±(50 ppm + 5% of reading)
- temp humidity accuracy
- ±0.2°C (0-65°C); ±2% RH (10-90%)