Smart Energy Metering IoT System — Sub-Metering for Commercial Buildings
An IoT sub-metering system installed across a 20-floor commercial tower, tracking energy consumption per tenant and floor in real time — reducing the building's total energy bill by 21% in 6 months.
⚠The Problem
The owner of a 20-floor commercial office tower received a single monthly utility bill with no visibility into which tenants or floors consumed the most energy. Tenant billing was estimated from square footage, creating disputes. HVAC was running at full capacity 24/7, including nights and weekends. Energy waste was estimated at 30–35% of total consumption.
💡Our Solution
We installed current transformer clamps at each floor's distribution board (no electrical rewiring), connected to PZEM-004T 3-phase meters via RS485, aggregated through ESP32 Modbus gateways, and published to AWS IoT Core. InfluxDB stores per-circuit energy at 1-minute intervals. A Lambda function calculates monthly tenant bills based on actual consumption and generates PDF invoices. An anomaly detection model flags circuits consuming energy outside business hours. The HVAC control integration automatically reduces setpoints on floors with no occupancy detected (via PIR sensor input).
🔗System Architecture
CT Clamps → PZEM Meters → ESP32 Modbus GW → MQTT → AWS IoT Core → InfluxDB → Lambda → React DashboardTech Stack
- 3-phase smart meter (PZEM-004T)
- ESP32 Modbus gateway
- Current transformers (CTs) per circuit
- Power factor meter
- RS485 bus wiring
- DIN-rail enclosures
- Modbus RTU → ESP32
- MQTT to cloud via Ethernet
- InfluxDB Line Protocol
- AWS IoT Core
- InfluxDB (energy time-series)
- Lambda (billing calculations)
- SES (automated tenant reports)
- React energy dashboard
- Per-tenant energy usage heatmap
- Demand forecasting charts
Key Features
Results Delivered
- 21% reduction in total building energy consumption in 6 months
- Tenant billing disputes reduced to zero (metered actuals)
- 40% reduction in HVAC runtime via occupancy-based scheduling
- Peak demand charges reduced by identifying and shifting loads
- Carbon footprint reporting enabled ESG compliance for tenants
Technologies
Who This Is For
Commercial building owners, facilities managers, energy management companies, utilities
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Frequently Asked Questions
What technology does this smart energy metering iot system use?+
Smart Energy Metering IoT System — Sub-Metering for Commercial Buildings is built on ESP32, Modbus, MQTT, React, InfluxDB. The stack was chosen for real-world reliability in a production deployment — full details are in the tech stack section.
Can CodeCaracal build a similar system for us?+
Yes. The same team that designed and deployed this energy / smart building system takes on new projects across the stack — firmware, connectivity, cloud and dashboards. Tell us your requirements and we will architect a solution for your environment.
Is this case study a real deployed system?+
Yes — every case study on this site describes a production system we designed and shipped. The problem, architecture, features and metrics are from the actual deployment.
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