WattNest
Smart Water Heater
Overview
Built an IoT controller and web dashboard to optimize water heating schedules, reducing peak load via demand-response and real-time telemetry.
Context
Water heating accounts for significant residential energy use. Smart scheduling can reduce costs and grid load by shifting heating to off-peak hours.
Constraints & Decisions
Constraints
Limited hardware budget, need for reliable edge computing, and integration with existing water heater systems. Must work offline and sync when connected.
Key Decisions
Built a Node.js-based edge controller with local scheduling logic, cloud sync for analytics, and a Next.js dashboard for user control. Used MQTT for device communication.
System
Edge controller runs on Raspberry Pi, communicates with water heater via relay control, and syncs telemetry to cloud. Dashboard provides scheduling interface and energy analytics.
Outcome
Demonstrated 15-20% energy cost reduction through optimized scheduling. System handles offline operation gracefully and provides clear user feedback.
Learnings
Learned IoT system design, edge computing patterns, and energy system integration. Gained experience as a founder building and shipping a complete product.