3 of the 13 features in our table differ between the SCD40 and the SCD41.
CO₂ · temperature · humidity · I²C · 2.4 to 5.5 V
Sensirion’s small photoacoustic CO₂ sensor: ±(50 ppm + 5 %) from 400 to 2,000 ppm, 2.4 to 5.5 V, I²C.
Watch out: Specified only up to 2,000 ppm: for greenhouses or higher levels, choose the SCD41.
CO₂ · temperature · humidity · I²C · 2.4 to 5.5 V
Like the SCD40 but specified to 5,000 ppm with ±(40 ppm + 5 %), plus a single-shot mode that averages 0.45 mA at one reading every 5 minutes.
Watch out: Costs more than the SCD40. Readings settle slowly: 60 s to reach 63 % of a change.
| Feature | SCD40 | SCD41 |
|---|---|---|
| CO₂ range | 400 to 2,000 ppm | 400 to 5,000 ppm |
| CO₂ accuracy | ±(50 ppm + 5 %) | ±(40 ppm + 5 %) |
| Lowest average current | 3.2 mA | 0.45 mA |
Same on both: measures · technology · interface · I²C address · supply · ESPHome · status.
In our table the SCD40 has nothing the SCD41 lacks: choose it for price, availability or a board you already have.
Open the sensor comparison →Tick what your project needs and see which sensor fits best.
SCD40: I²C address, wiring and pull-ups →
SCD41: I²C address, wiring and pull-ups →
The SCD41 offers better CO₂ accuracy, a wider CO₂ range, and a lower average current; in our table the SCD40 has no advantage of its own, apart from price or availability.
Both measure real CO₂: ±(50 ppm + 5 %) for the SCD40 (400 to 2,000 ppm), ±(40 ppm + 5 %) for the SCD41 (400 to 5,000 ppm).
Often yes: both use I²C and the same ESPHome component (scd4x), so mostly the settings change.
SCD40 vs MH-Z19C SCD40 vs SCD30
Figures from the makers’ datasheets and product pages and the ESPHome documentation, checked in November 2026.