- 1. Indicative savings in buildings with connected HVAC and sub-metering; depends on project and baseline.
- 2. Aggregated roaming coverage; exact list varies by country and operator.
- 3. Aggregated multi-carrier access; automatic failover to the best available operator.
- 4. Estimated network availability; formal SLA available in Enterprise plans.
Key features
HVAC monitoring
Telemetry from HVAC equipment, fan-coils and chillers. Early fault detection and data-driven predictive maintenance.
Lighting control
Switching and dimming based on occupancy and daylight. Up to 40% electricity savings vs. conventional fixed lighting.
Energy sub-metering
Connected sub-meters per floor, zone or equipment for cost allocation and anomalous-consumption detection.
Indoor air quality
CO2, VOC, PM2.5 and humidity sensors to validate ventilation and comply with workplace and healthcare regulations.
Occupancy and capacity
Real-time people counting to optimize space usage, capacity-based HVAC and regulatory compliance.
BMS / BACnet / Modbus integration
IoT-SIM gateway connects the existing BMS to the cloud without touching the corporate network. Optional private APN for segregated traffic.
Use cases
Typical problems
- Old BMS isolated from the cloud because IT won't open ports in the corporate firewall — HVAC data stays trapped on serial RS-485.
- Sub-meters installed but offline because the building WiFi doesn't reach the basement-2 electrical panel.
- Multiple proprietary gateways (one per vendor: Carrier, Daikin, Trane, Honeywell) that don't talk to each other or to the central O&M platform.
- Air quality sensors installed only at floor level with no fallback network — if the floor WiFi drops, data is lost and the audit is incomplete.
- BACnet/MS-TP sub-meters that need a single physical integrator per floor and multiply install cost.
- Legacy systems with serial protocols (Modbus RTU, M-Bus) that need an IP converter before they can reach the cloud.
Recommended architecture
- 1
Industrial gateway with IoT SIM at each technical panel
One cellular router (Teltonika RUT240 or equivalent) per main panel and per-floor sub-panel concentrates field buses (Modbus TCP/RTU, BACnet/IP, M-Bus) and exposes them to the cloud. Independent of the corporate network.
- 2
Serial-to-IP converters on sub-buses
M-Bus → Modbus TCP, BACnet/MS-TP → BACnet/IP converters in each sub-zone. The central gateway aggregates everything into a single cellular uplink to reduce SIM cost.
- 3
Private APN with VPN to the O&M integrator's cloud
Traffic never touches the public Internet — IPsec tunnel into the integrator's VPC. Compliance-friendly with GDPR for occupancy data (which can infer presence).
- 4
Per-gateway data plan, not per-sensor
One gateway concentrates 50-200 field points (HVAC, lighting, sub-meters, IAQ probes) and uses 100-500 MB/month. One SIM per floor is the sweet spot, not one SIM per device.
Indicative data plan
| Device | Typical monthly traffic | Recommended plan |
|---|---|---|
| Central per-floor gateway (HVAC + lighting + sub-meters) | 100-500 MB/month | 500 MB plan |
| LTE-M standalone IAQ probes (CO2, VOC, PM2.5, battery) | 1-5 MB/month | Smart-meter 5 MB plan |
| Occupancy / people-counting camera (events + thumbnails) | 200 MB - 1 GB/month | 1 GB plan |
| Standard IP electric sub-meter (15-min reads) | 10-30 MB/month | Smart-meter 50 MB plan |
Indicative figures. Continuous streaming reports (live capacity cameras, BIM-stream) can multiply consumption. Request sizing with the specific gateway firmware.
When to use static IP
- The integrator's central BMS needs to initiate connection to each per-floor gateway for remote schedule or setpoint reconfiguration.
- Regulatory audit (ISO 50001 for energy management, ENS for public buildings) requires per-IP gateway traceability.
- Integration with BACnet/IP platforms that need a stable endpoint for Who-Is/I-Am discovery.
When to use private APN
- Occupancy, sub-metering, and BMS data must NOT leave the integrator's controlled environment (GDPR, end-customer professional secrecy).
- Customer is critical infrastructure (bank, hospital, corporate HQ) and demands end-to-end private network.
- BIM digital-twin integration that requires stable RFC1918 addressing to correlate gateway data with model elements.
Compatible devices
Teltonika RUT240 / RUT956 / RUTX10
Industrial routers with 2FF SIM, Modbus TCP/RTU gateway support, OpenVPN, MQTT pub/sub. Standard in BMS projects for cost/feature ratio.
MOXA UC-2100 / UC-3100 series
Industrial IIoT gateways with optional cellular, BACnet/IP support, protocol-to-protocol conversion. For deployments with high reliability requirements.
Aranet4 / Awair Element / Senseair IAQ probes
Standalone CO2, temperature, humidity, VOC and PM2.5 sensors. Some with direct LTE-M (no intermediate gateway); others via LoRaWAN or BLE.
Schneider iEM / ABB B-series sub-meters
Electric sub-meters with built-in Modbus RTU/TCP. They connect to the gateway over the bus, no SIM of their own.
PointGrab / Density / Steinel occupancy sensors
PIR, ToF or camera sensors with on-edge analysis. Report to the gateway via LoRaWAN or local WiFi; rarely with direct SIM.
M-Bus / BACnet converters (Relay PadPuls, Anybus)
To bring legacy M-Bus meters or BACnet/MS-TP BMS into the IP gateway. Low cost and critical for retrofits in older buildings.
Frequently asked questions
- Why not use the building's corporate WiFi for the BMS gateway?
- It works, but the BMS then depends on the IT provider's SLA and any SSID/encryption/policy change. A dedicated SIM at the BMS gateway is independent, segregated from corporate traffic, and simplifies security audit. In practice, the cost of an industrial SIM (€5-15/month) is negligible compared to the cost of a BMS down because of an IT change.
- Do I need one gateway per floor or one central gateway per building?
- Depends on size and existing wiring. Small buildings (<5,000 m²) work with a central gateway + LoRa/BLE extenders. Large buildings or those with distributed technical floors need a per-floor or per-panel gateway to avoid relying on a kilometer-long single bus (more failures, more latency).
- How does gateway data integrate with platforms like Schneider EcoStruxure or Siemens Desigo?
- Gateways export over MQTT, REST or BACnet/IP, which modern BMS platforms consume directly. For legacy systems that only speak BACnet/IP, configure the gateway as a BACnet Bridge — it presents each field point as a BACnet object on the customer's IP network.
- Do LTE-M IAQ probes use a lot of data?
- Typical hourly reports use less than 1 MB/month. Alarm events (CO2 > threshold) add little. A 5 MB/month smart-meter SIM is enough with 5x headroom. Standalone probe batteries last 2-5 years with 1-6 hour reports.
- Are we GDPR-compliant if we log occupancy data?
- Yes, if the data is aggregate (people count) and non-identifying (cameras with on-edge analysis that count without recording). If you record video or use facial recognition, you enter full GDPR territory and need explicit legal basis + DPIA. For simple capacity counting, anonymous aggregate data = low risk.
- Can I control HVAC setpoints remotely from the cloud?
- Yes, if the gateway supports it and you have static IP (so the central platform can initiate the connection). Important: limit allowed ranges in the gateway firmware — never let the cloud send arbitrary setpoints without local validation. A poorly secured API that turns off a hospital's heating is catastrophic.
Pre-deployment checklist
- 1Per-floor equipment inventory: BMS, HVAC, lighting, sub-meters, IAQ probes, occupancy sensors. Protocol and bus for each.
- 2Map of electrical and technical panels — physical location of each candidate gateway.
- 3Cellular coverage at each technical panel (basements, plant rooms) before choosing SIM — measure RSSI/RSRP with a test phone.
- 4Central gateway vs per-floor gateway decision based on size and dispersion.
- 5Static vs dynamic NAT IP decision — documented per gateway.
- 6Private vs public APN based on customer requirements (corporate, hospital, retail).
- 7Per-gateway data plan with 3x headroom and auto-block at 4x to avoid bill surprises.
- 8Gateway SIM replacement procedure for failures — local stock or express shipping?
- 9ISO 50001 (energy management) compliance and, if applicable, ENS / GDPR for occupancy data.
- 10Pilot of 2-3 floors for 2 months validating bus uptime, remote command latency, and reading accuracy vs manual verification.
Need a printable version? See the pre-deployment guide.
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