After my second Ecobee died in the middle of a heat wave a few weeks out of warrantee, I decided to replace it with an ESPHome Climate Controller.
- Quad relay ESP32 module
https://www.aliexpress.com/item/2255799905174014.html
This one takes 24VAC supply directly (R and C wires – my own furnace supplies 28VAC and it is fine). Be sure to specify you want a “test board” so you can reflash it. The header pin assignment (and tons of other info) can be found here.
Note: You need external power to re-program it. Powering using the 3.3V header on the debug port is not sufficient.
- Temperature Sensor
I’m reusing the interior temperature sensor I already have
https://www.aliexpress.com/item/3256804542206729.html
- ESPHome Climate Configuration
Being located in the US, I use Fahrenheit instead of Celsius (I know, I know, I’m Canadian and hate it too). There is a problem in that temperature sensors are reported in C but ESPHome does not convert them into F even if you specify the measurement unit as such. Thus a conversion lambda is necessary. Specifying F everywhere else works fine.
sensor:
- platform: homeassistant
id: temperature_sensor
name: "Temperature Sensor From Home Assistant"
entity_id: sensor.th_inside_temperature
unit_of_measurement: °C
filters:
- lambda: return (x - 32.0) * 5.0/9.0;
switch:
- platform: gpio
pin: GPIO16
id: G
name: "Fan"
- platform: gpio
pin: GPIO02
id: W1
name: "Low Heat"
- platform: gpio
pin: GPIO32
id: W2
name: "High Heat"
- platform: gpio
pin: GPIO12
id: Y
name: "Cool"
# Dual-point Climate Controller
# See https://www.techsolutions.support.com/how-to/how-to-set-a-threshold-on-an-ecobee-thermostat-12429
# for sensible values
climate:
- platform: thermostat
name: "Thermostat Climate Controller"
sensor: temperature_sensor
cool_deadband: 2 °F
cool_overrun: 2 °F
heat_deadband: 2 °F
heat_overrun: 2 °F
min_cooling_off_time: 300s
min_cooling_run_time: 300s
min_heating_off_time: 300s
min_heating_run_time: 300s
min_fanning_off_time: 30s
min_fanning_run_time: 30s
min_idle_time: 300s
set_point_minimum_differential: 3 °F
cool_action:
- switch.turn_on: Y
heat_action:
- switch.turn_on: W1
max_heating_run_time: 300s
supplemental_heating_delta: 5 °F
supplemental_heating_action:
- switch.turn_on: W2
idle_action:
- switch.turn_off: G
- switch.turn_off: W1
- switch.turn_off: W2
- switch.turn_off: Y
fan_only_action:
- switch.turn_on: G
fan_with_cooling: True
fan_with_heating: True
default_preset: Home
on_boot_restore_from: memory
preset:
- name: Home
default_target_temperature_low: 68 °F
default_target_temperature_high: 78 °F
mode: HEAT_COOL
- name: Comfort
default_target_temperature_low: 70 °F
default_target_temperature_high: 74 °F
mode: HEAT_COOL
- name: Sleep
default_target_temperature_low: 65 °F
default_target_temperature_high: 70 °F
mode: HEAT_COOL
- name: Away
default_target_temperature_low: 50 °F
default_target_temperature_high: 85 °F
mode: HEAT_COOL
- name: OverCool
default_target_temperature_low: 60 °F
default_target_temperature_high: 65 °F
mode: COOL
- Wiring
The common terminal of all relays is wired to R and the G/W1/W2/Y wires are connected to the Normally-Open (NO) terminal of the corresponding relay. This got mounted on the wall in the mechanical room (turn off power to the furnace when doing the actual wiring!). I added a cut off switch in case it needs to be taken out of service.
- Created a climate control panel on my wall console, along with schedules and “It’s hot!”, “It’s cold!”, and “We’re away” helpers that are used as conditions in the schedules.
The gorgeous temperature forecast is courtesy of the Clock Weather Card.
Automation (there are two more like it) making sure only one climate mode is turned on:
alias: When Climate Set to Summer
description: ""
trigger:
- platform: state
entity_id:
- input_boolean.it_s_hot_outside
to: "on"
condition: []
action:
- service: input_boolean.turn_off
metadata: {}
data: {}
target:
entity_id:
- input_boolean.it_s_cold_outside
- input_boolean.we_re_on_vacation
- service: climate.set_temperature
metadata: {}
data:
temperature: 50
target:
entity_id:
- climate.master_bathroom
- climate.main_bathroom
- service: climate.set_temperature
metadata: {}
data:
target_temp_high: 76
hvac_mode: cool
target_temp_low: 65
target:
entity_id: climate.house_thermostat_thermostat_climate_controller
mode: single
- Installed a dumb thermostat as a back up
Should HA go off-line or my ESP board die, I can shut it off and simply turn on my dumb thermostat. It also nicely covers the hole in the wall.
