I have a pretty simple smart thermostat without many fancy features. Every Spring and Fall I tell myself I should set up some kind of system where if the outdoor weather is good enough, maybe I dial back the heating / cooling, maybe send myself a text to open windows, etc.
Small example: I normally keep my house at 72 in the summer, but if it’s up to 76 or so outside, it’d be nice if the thermostat turned off the cooling. I could manually turn it back on if I have guests over, etc.
I’m sure some of this logic would be easy to code myself, but wanted to check out what anyone else is doing first.
Using home assistant.
I have one where I put a door/window sensor on a window and anytime that window is opened it turns off the HVAC, then when closed, turns it back on.
I tried once to setup a notification to open the windows if the weather was nice, but I’d never gotten to work quite like I wanted, and so I turned it off.
Using the Ecobee thermostat, I use the built in weather module in Home Assistant to give local weather data to the system. In summer, I set it up to watch for the lowest overnight temps via forecast, and trigger on the lowest temperatures we’d see. Then I’d drop the house temp to 66 or 64 degrees when the AC had to do the least amount of work. Then I’d use the basement air to keep the upstairs cool enough and use the AC as little as possible.
My last house was old and had some drafts I couldn’t find. So in the winter, if the weather turned to windy I’d increase the temp a degree or two for comfort.
I don’t have a thermostat, but I have indoor and outdoor temp and humidity sensors, and a window position sensor. HA notifies me (via lighting color) if I should open the window because the outdoor conditions are better than indoors, or vice versa.
I have some logic around notifications and a few actions. My spouse and I both grew up in houses with heat, but no AC, so I’ve programmed HA to send notifications to our phones if the setpoint on our Ecobee thermostat is warmer than the outside temperature in Cooling mode, and cooler than the outside temp in Heating mode. Outdoor temps are a blend of three weather service feed “feels like” observations and two outdoor temperate/humidity sensors.
The outdoor sensors are a ZigBee sensor, and some area sensors I snoop a few times an hour with an RTL-SDR radio single via MQTT bus. I have a helper that blends the weather service and local obs to compare with the thermostat. It bothers us every 2 hours to open some windows.
We both also have a bad habit of not closing the back door all the way, so the Assistant bugs us if a door or window is open for more than 10 minutes and the outdoor temperature is below the heating setpoint, or above the cooling setpoint. It turns off the HVAC a few minutes later if the condition persists and sends a snarky notification about not being made of enough money to fix climate change. However, it will turn the heat back on to 60F if the house falls below 58F and send notifications every hour til the condition is addressed.
Otherwise the ecobee does a fair job adjusting itself to maintain a desired inside temp on its own.