Smart Home Climate Control Mobile App Development
Thermostats, air conditioners, heat recovery systems, radiant floor heating — one apartment can have equipment from three different manufacturers with different protocols. The mobile app's task is to present a unified interface and provide control without needing to switch between five different applications.
Climate Equipment Protocols
Nest Thermostat — Google Smart Device Management (SDM) API. OAuth2, REST. Supports temperature control (sdm.devices.commands.ThermostatTemperatureSetpoint.SetHeat), mode (Heat/Cool/HeatCool/Off), reading current temperature from built-in sensor.
Ecobee — proprietary REST API with PIN-based OAuth2. Endpoint POST /1/thermostat for updating settings. Supports schedules (climate), occupancy detection via PIR sensors.
Mitsubishi, Daikin, LG ThinQ — typically cloud APIs with limited or no public documentation. Real-world solution — integration via Home Assistant (climate domain) or homebridge as middleware.
Zigbee/Z-Wave thermostats (Eurotronic, Danfoss) — via Zigbee2MQTT or Z-Wave JS. Command setpoint_type, setpoint to MQTT topic.
Modbus — for commercial HVAC systems, boilers, chillers. Modbus TCP via local network. Mobile app → backend → Modbus TCP → device.
Thermostat Interface: What Matters
The main thermostat screen in a mobile app is a circular control with target temperature, current temperature, and mode. Standard components don't fit. You need to draw a custom widget.
On Flutter — CustomPainter with Canvas.drawArc, Canvas.drawPath. Interactivity via GestureDetector with onPanUpdate: calculate touch angle relative to center, convert to temperature. Smoothness — AnimationController with CurvedAnimation.
Temperature range typically 5–35°C. Step: 0.5°C or 1°C. Haptic feedback when reaching target — HapticFeedback.selectionClick() on iOS, HapticFeedback.vibrate() on Android.
Important: don't send MQTT/REST commands for every rotation step. Debounce 500ms + mandatory send on onPanEnd. Otherwise Nest thermostat starts ignoring requests with too frequent changes (rate limiting: 1 request per second per device).
Climate Scheduling and Automation
Heating/cooling schedule — weekly grid with time slots. Each slot: start time, target temperature, mode. UI — horizontal timeline for a day, swipe to switch days.
Implementation on Flutter: CustomScrollView with horizontal PageView for days and Stack for timeline. Tap on slot — showBottomSheet with settings.
Complex case: the app must account for vacation mode. User sets date range — system ignores schedule, maintains economy mode. After return (geolocation or manual confirmation) — switch back to normal mode.
Multi-zone Climate
Apartment split into zones, each zone has its own thermostat or radiator valve. Display floor plan (SVG or Canvas) with overlaid temperature widgets. Tap on room — detailed screen for that zone.
SVG plan loaded as asset or from server. On Flutter use flutter_svg + GestureDetector on each SVG area. On React Native — react-native-svg with similar approach.
Sync states across all zones — via WebSocket from backend. Don't use polling: with 10 thermostats polling every 30 seconds — 20 requests per minute per phone. At 1000 users — 20,000 requests per minute. WebSocket with push updates on changes — the right approach.
Integration with External Sensors
CO2 sensors (Aranet4, Netatmo) — influence ventilation decisions. Humidity sensors — for dehumidifier control. Outdoor weather station — for heating threshold adjustment.
Aranet4 data via Bluetooth BLE (GATT characteristics) or through Aranet Cloud API. flutter_blue_plus for BLE reading on Flutter. BLE polling once per 1–5 minutes — sensor battery is not infinite.
Timeline
Integration with one system (e.g., Nest + scheduling + basic control) — 6–8 weeks. Multi-zone climate, multiple protocols, floor plan, automation — 3–5 months. Cost determined after auditing customer's equipment.