Home assistant & Nest SDM API blower control

Hardware
1

I am willing to buy a Home Assistant Green, but before I do, I’d like to verify its official integration with the Nest SDM API specific to being able to control a Nest Gen 3 blower motor function.

I have a bilevel home with a cold basement and roommates who don’t like it as cold as I do. But with a brown roof I need a/c and am trying to minimize running it and driving my basement roommates nuts so am trying to find a solution.

I’d like to cook some code so that once temps upstairs reach say 72, the blower motor turns on for specific and perhaps gradually increasing times triggered by thermostat until it reaches like 74 and then would kick on a/c and then have a time based stop to say at 4:30 PM, turn a/c off and turn blower motor on until outside temp reaches 71.

I put in a fresh air return which is making s difference in keeping the basement from being too fridgid given the thermodynamics of my home as despite sealing upstairs from down and closing basement registers, when it’s 74 upstairs it’s like 63-66 downstairs. My roommate finds that unbearable, and because of brown roof it gets hot in the afternoon upstairs where my dog lives too.

Unfortunately my environmental allergies have gotten worse as I’ve gotten older and as it’s the Rockies my old energy conserving strategy of opening windows at night and closing them early and leaving shades shut is untenable given increasingly poor air quality due to summer wildfires. There’s some carbon filter material that’s expensive but it’d involve basically eliminating light when things get bad and labor intensive to build frames for modular material installation to return to it, and costly.

So, basically the Nest app (Gen 3) only allows you to do blowe motor schedule for 0.25 increments of an hour up to 3 between certain hours.

So I found Home Assistant through searching and then asked AI if it could verify compatibility but Gemini suggested that there was not functionality through the API integration to send commands but only to change state and thought that switching state on gen 3 to blower only then having my regular a/c schedule but could not verify if it could be switching state to ‘blower only’ if it could actually start the blower then switch to cool mode when triggered by thermostat.

Thanks in advance for advice.

Plus it would help conserve energy doing it this way too.

2

From your integration documentation I found the nest integration and there’s a note that all thermostats are supported with the API through device management but a blue note that temperature sensors are not. I’m unsure if that means that the integration does not support reading temperatures on the thermostat inside. But I think after reading through the link above it does appear that I could do what I want to do.

I’m only novice as a coder but also am not afraid to play until I get something to work. I was able to use IFTT and tasker to turn off all lights when I place my phone on a Qi charger so I figured sooner or later I’ll figure it out.

While anyone is at it, is there a way to to access real time forecast data within two hours of my locale and trigger different actions based on it? I presume so, but I want to be sure before buying.