AM103 vs EM500-CO2: indoor room sensor or sealed CO2 sensor?
Short answer: Both measure CO2 with an NDIR sensor from 400 to 5,000 ppm, to ±(30 ppm + 3% of reading), plus temperature and humidity, over LoRaWAN. The AM103 is a small IP30 room sensor with an E-Ink screen and a traffic light indicator, for offices and classrooms. The EM500-CO2 is an IP65 sensor rated from -30°C to 70°C that adds barometric pressure and a 19,000 mAh battery, for cellars, plant rooms, farm buildings and anywhere damp, dusty or cold.
Where will it be mounted?
Choose the AM103 for occupied indoor rooms. It measures 68 × 65 × 20.5 mm, mounts with tape or screws, and its traffic light LED shows the CO2 state in the room without a dashboard. The AM103L is the same sensor without the screen. It operates from -20°C to 60°C, with the E-Ink screen rated from 0°C to 40°C.
Choose the EM500-CO2 for harsh or unheated spaces. It is IP65, rated from -30°C to 70°C, mounts on a pole, wall or DIN rail, and also measures barometric pressure from 300 to 1,100 hPa.
Accuracy and battery
CO2 accuracy is specified identically. Temperature and humidity differ slightly: the AM103 reads to ±0.2°C between 0°C and 60°C and ±2% RH at 25°C, the EM500-CO2 to ±0.3°C between 0°C and 70°C and ±3% RH between 10% and 90%.
The AM103 runs around 4.5 years at SF7 on two replaceable ER14505 cells at a 10 minute interval. The EM500-CO2 has a replaceable 19,000 mAh cell rated for 10 years at a 10 minute interval.
What neither is
Both top out at 5,000 ppm, so neither is a CO2 gas safety alarm for spaces where a leak can push levels far higher, such as a beer cellar with CO2 cylinders. They monitor ventilation and trends alongside a proper gas alarm.
Milesight AM103 / AM103L Indoor Ambience Monitoring Sensor
AM103
Price range: £127.19 through £142.15 ex VAT (£152.63 – £170.58 inc. VAT)
DisplayAM103: 2.13-inch Black & White E-Ink Screen (AM103L: Not Support)
View the AM103
Milesight EM500-CO2 CO2 Sensor (4 in 1)
EM500-CO2-868M
£179.56 ex VAT (£215.47 inc. VAT)
CO2 measuring range400 - 5000 ppm (NDIR), ± (30 ppm + 3% of reading)
View the EM500-CO2-868MSpecification comparison
| Specification | AM103 | EM500-CO2-868M |
|---|---|---|
| Advanced features | Calibration, Threshold Alarm, Data Storage (640 entries), Data Retrievability, Data Retransmission, Screen Hibernate Mode, Smart Screen Mode | Data storage (1,000 entries), data retransmission, data retrievability, threshold alarm, calibration |
| Approvals | CE, CE(RED), FCC, ISED; RoHS | CE, FCC, LoRaWAN® Certified, ISED, ICASA, Telec; EN62368-1; RoHS |
| CO2 accuracy | ±(30 ppm + 3 % of reading) (0°C to +50°C) | ± (30 ppm + 3% of reading) (0°C - 50°C, 0 - 85% RH) |
| CO2 range | 400 to 5000 ppm | 400 - 5000 ppm |
| CO2 sensor type | Nondispersive Infrared (NDIR) | NDIR |
| Configuration | Mobile App via NFC, Downlink | Mobile app via NFC, PC software via USB Type-C, downlink |
| Ingress protection | IP30 | IP65 |
| Installation | Wall Mounting via 3M Tape or Screws | Pole, wall or DIN rail mounting |
| Operating temperature | -20°C to +60°C (E-Ink Screen: 0°C - 40°C) | -30°C to +70°C |
| Power supply | 2 × 2700 mAh ER14505 Li-SOCl2 Replaceable Batteries | 1 × 19000 mAh ER34615 Li-SOCl2 battery (replaceable) |
| Sensitivity | -137dBm @300bps | -137 dBm @300bps |
| Tx power | 16 dBm (868 MHz)/22 dBm (915 MHz)/19 dBm (470 MHz) | 16 dBm (868 MHz) / 20 dBm (915 MHz) / 19 dBm (470 MHz) |
| Wireless technology | LoRaWAN®, internal antenna | LoRaWAN® |
| Barometric pressure | — | 300 - 1100 hPa; ± 1 hPa; 0.1 hPa resolution |
| Battery life | — | 10 years (10 min interval, 25°C) |
| Battery life (AM103, 10 min interval, 25°C) | Around 4.5 Years (SF7, EU868 & US915); Around 3 Years (SF10, EU868); Around 2.3 Years (SF10, US915) | — |
| Dimensions | 68 × 65 × 20.5 mm (2.68 × 2.56 × 0.81 in) | — |
| Dimensions / weight | — | 147.9 × 71 × 69.5 mm; 434.7 g (with battery and mounting bracket) |
| Display | AM103: 2.13-inch Black & White E-Ink Screen (AM103L: Not Support) | — |
| Housing & colour | PC + ABS, White | — |
| Humidity | — | 0% to 100% RH; ± 3% (10-90% RH), ± 5% below 10% and above 90%; 0.5% RH resolution |
| Humidity accuracy | Typ. ±2% RH (25°C) | — |
| Humidity range | 0% ~ 100% RH | — |
| Humidity resolution | 0.5% RH | — |
| LED | 1 × Traffic Light Status Indicator | — |
| LoRaWAN mode | — | OTAA/ABP Class A |
| Measured parameters | Temperature, humidity and CO2 | — |
| Mode | OTAA/ABP Class A | — |
| Relative humidity | — | 0% to 95% (non-condensing) |
| Relative humidity (operating) | 0% to 95% (non-condensing) | — |
| Temperature | — | -30°C to +70°C; ± 0.3°C (0 to +70°C), ± 0.6°C (-30 to 0°C); 0.1°C resolution |
| Temperature accuracy | Typ. ±0.3°C (-20°C ~ 0°C), ±0.2°C (0°C ~ 60°C) | — |
| Temperature range | -20°C ~ 60°C | — |
| Temperature resolution | 0.1°C | — |
| Transmission range | — | Line of sight up to 10 km |
| Weight | 182.5g (Batteries included) | — |
| CO2 resolution | 1 ppm | 1 ppm |
| Frequency | CN470/IN865/RU864/EU868/US915/AU915/KR920/AS923-1&2&3&4 | CN470/IN865/RU864/EU868/US915/AU915/KR920/AS923-1&2&3&4 |
Specifications taken from the manufacturer datasheets. Rows where the models are identical are dimmed. Prices are ex VAT and read live from the catalogue.
Frequently asked questions
Do the AM103 and EM500-CO2 measure CO2 the same way?
Yes. Both use an NDIR sensor over 400 to 5,000 ppm with an accuracy of u00b1(30 ppm + 3% of reading) and 1 ppm resolution.
Which is better for a classroom or office?
The AM103. It is sized for indoor rooms, and its E-Ink screen and traffic light LED show conditions to the people in the room.
Which is better for a cellar or livestock building?
The EM500-CO2. It is IP65, rated from -30u00b0C to 70u00b0C, and mounts on a pole, wall or DIN rail.
Is either a CO2 safety alarm?
No. Both read up to 5,000 ppm and are monitoring sensors. Spaces with CO2 cylinders need a fixed gas detection alarm.