Automating a whole house exhaust fan

Other Devices & Integrations Climate Control & Temperature Sensors
#1

Hardware:

  1. Whole house exhaust fan plugged into a Z-Wave outlet
  2. Aeon 4-in-1 sensor (outside for temperature and humidity)
  3. Aeon 4-in-1 sensor (inside for temperature)
  4. Vera Plus controller (for the programming)
  5. Ecobee thermostat

Vera ON script; Turn exhaust fan ON when ALL of the following are true (and condition);

  1. Aeon 4-in-1 sensor outside air temperature less than 72 degrees (only pull in cool air).

  2. Aeon 4-in-1 sensor outside humidity less than 75% (don’t pull in overly humid air).

  3. Aeon 4-in-1 sensor outside humidity greater than 30% (don’t pull in overly dry air).

  4. Aeon 4-in-1 sensor inside temperature greater than 72 degrees (turn on exhaust only when needed).

Vera OFF script; Turn exhaust fan OFF when ANY of the following are true (or condition);

  1. Aeon 4-in-1 sensor outside air temperature greater than 72 degrees (too warm outside to help much).

  2. Aeon 4-in-1 sensor outside humidity is greater than 75% (too humid).

  3. Aeon 4-in-1 sensor outside humidity is less than 30% (too dry).

  4. Aeon 4-in-1 sensor inside temperature is less than 72 degrees (turn off exhaust when cooling is no longer needed).

Vera ON script; Ecobee set to AWAY when fan is running. This can be done with the standard Ecobee Vera app.

Vera OFF script; Ecobee RESUME when fan is off. The Ecobee app does not support a resume function, so this has to be done via LUUP code (replace xxxx with your device number);

local service_id = “urn:ecobee-com:serviceId:Ecobee1”
local action = “ResumeProgram”
local args = {resumeAll=“true”}
local dev_num = xxxx
luup.call_action(service_id, action, args, dev_num)

Outside Aeon 4-in-1 needs to be more responsive than default.
111=300 4 byte Dec
113=300 4 byte Dec
101=225 4 byte Dec

#2

I use this to control two attic fans. No need to complicate things to connect to vera

RANCO ETC-111000 Digital Cold Temperature Control NEW

I have both set to turn on when the attic temp reaches 90F and turn off at 85F

Easy to install

Howard

#3

Automating a whole house fan can be easier LOL. But… when I controlled it just with temperature, it would pull in some massively soggy air during heat waves (like we are going through recently in California).

#4

Don’t forget to put checks in the code to ensure that windows or doors are open. You do NOT want to create a negative pressure situation where its pulling air from the chimney or any NG sources in your home such as a water heater. Also put some debounce timer logic in so that it wont turn on and off constantly. I have a pretty locked in house fan automation that took a few months to get right. Its a dual speed fan controlled by two Qubino relays (after my crappy Linears died as expected) . The relays control power through a fan capacitor to do reduced speed.

Start: (30s start timer initiated)
Uses the Ecobee set points as the target temp. (thermostat changes during the day/night). Must exceed cold set point
starts only of a 7 degree differential from the outside. (uses DarkSky / Wunderground PWS)
humidity needs to be below a set level.
at least two windows open.
Thermostats must be set to off (windows/doors open over 90s shuts down the thermostats)
Open high relay, and close slow relay. when sleep is initiated or if the temp is between the cold and hot set points.
If after 30s, all still true, start fan

Stop:
WIndows open <2 or
Temp has reached the heat set point or
Thermostat switches out of Off Mode. or
Humidity exceeds X value or
override button set or

#5

I agree that controlling a whole house fan could be easier. But you’ve done a great work!
I’m not an advanced user of all this stuff and I still need Vera to control my QuietCool, especially when I’m not at home.
Thanks for sharing