This project creates an energy-saving HVAC control system that automatically adjusts temperature settings based on room occupancy. When a room is occupied, the system maintains normal temperature; when the room is empty for a set period, it enters an energy-saving mode with a temperature setback. This can reduce heating and cooling costs by 10-20% annually.<\/p>\n
Difficulty:<\/strong> Intermediate PIR sensors placed in key rooms detect occupancy. When no motion is detected for a set period, the system sends a signal to the HVAC system to adjust the temperature setpoint (higher for cooling, lower for heating). When occupancy is detected again, the system returns to the normal setpoint.<\/p>\n This occupancy-based HVAC control system automatically reduces energy waste when rooms are empty, lowering utility bills without sacrificing comfort.<\/p>\n","protected":false},"excerpt":{"rendered":" Project Overview This project creates an energy-saving HVAC control system that automatically adjusts temperature settings based on room occupancy. When a room is occupied, the system maintains normal temperature; when the room is empty for a set period, it enters an energy-saving mode with a temperature setback. This can reduce heating and cooling costs by […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-4128","post","type-post","status-publish","format-standard","hentry","category-projects"],"blocksy_meta":[],"yoast_head":"\r\n
\nEstimated time:<\/strong> 3-4 hours
\nEstimated cost:<\/strong> $30-50<\/p>\nHow It Works<\/h2>\n
Materials Needed<\/h2>\n
\n
Home Assistant Setup<\/h2>\n
\n
ESPHome Configuration<\/h2>\n
esphome:\n name: occupancy_sensors\n\nesp32:\n board: esp32dev\n\nwifi:\n ssid: \"YourWiFiSSID\"\n password: \"YourWiFiPassword\"\n\napi:\n password: \"YourAPIPassword\"\n\nbinary_sensor:\n - platform: gpio\n pin: GPIO4\n name: \"Living Room Motion\"\n device_class: motion\n filters:\n - delayed_on: 100ms\n - delayed_off: 60000ms\n \n - platform: gpio\n pin: GPIO5\n name: \"Bedroom Motion\"\n device_class: motion\n filters:\n - delayed_on: 100ms\n - delayed_off: 60000ms\n<\/code><\/pre>\nHome Assistant Automations<\/h2>\n
# configuration.yaml\nautomation:\n - alias: \"HVAC - Enter Away Mode\"\n trigger:\n - platform: state\n entity_id: \n - binary_sensor.living_room_motion\n - binary_sensor.bedroom_motion\n to: \"off\"\n for: \"00:30:00\"\n condition:\n - condition: state\n entity_id: binary_sensor.house_occupied\n state: \"on\"\n action:\n - service: climate.set_temperature\n target:\n entity_id: climate.main_thermostat\n data:\n temperature: 62\n - service: input_boolean.turn_off\n target:\n entity_id: input_boolean.house_occupied\n\n - alias: \"HVAC - Return to Normal\"\n trigger:\n - platform: state\n entity_id: \n - binary_sensor.living_room_motion\n - binary_sensor.bedroom_motion\n to: \"on\"\n condition:\n - condition: state\n entity_id: binary_sensor.house_occupied\n state: \"off\"\n action:\n - service: climate.set_temperature\n target:\n entity_id: climate.main_thermostat\n data:\n temperature: 68\n - service: input_boolean.turn_on\n target:\n entity_id: input_boolean.house_occupied\n<\/code><\/pre>\nStandalone Arduino Version<\/h2>\n
\/\/ Standalone HVAC Controller with PIR\nconst int pirPin = 4;\nconst int relayPin = 5;\n\nunsigned long lastMotionTime = 0;\nconst unsigned long setbackDelay = 1800000;\nbool inSetback = false;\n\nvoid setup() {\n pinMode(pirPin, INPUT);\n pinMode(relayPin, OUTPUT);\n digitalWrite(relayPin, LOW);\n delay(60000);\n}\n\nvoid loop() {\n bool motion = digitalRead(pirPin) == HIGH;\n \n if (motion) {\n lastMotionTime = millis();\n if (inSetback) {\n digitalWrite(relayPin, LOW);\n inSetback = false;\n }\n }\n \n if (!inSetback && (millis() - lastMotionTime > setbackDelay)) {\n digitalWrite(relayPin, HIGH);\n inSetback = true;\n }\n \n delay(100);\n}\n<\/code><\/pre>\nInstallation Steps<\/h2>\n
\n
Conclusion<\/h2>\n