As I've pointed out before, home IoT ought to include duct damper controls, vents and fans to the outside, and sensors which measure temperature, humidity, CO2, and maybe other pollutants, both inside and outside the house. Then they can use outside air when appropriate. You can buy all that. It's common in commercial building control. Honeywell and Johnson Controls, old-line building control vendors, sell this stuff. It requires some engineering for each building. That's why it's rarely seen in homes.

Some years ago I went to an IoT meeting in the Dogpatch area of San Francisco. The meeting was in a big room on the waterfront, in a refurbished industrial space. The room had skylights with glass vents that could be opened and windows onto the Bay that could be opened. Both were controlled by a manual endless chain, which could have been motorized without too much trouble. There were ceiling fans, and a standard dumb HVAC system. None of this stuff was interconnected. With a big group in there, it should have sensed rising CO2, opened some of the windows, cranked up the fans, and run the room without active HVAC until sunset. Then it should have gradually closed the windows as the room cooled, kept the ceiling fans turning over, and added some heat. Once everyone left, it should have briefly ventilated the room thoroughly, then closed up everything, stopped the fans, and let the room cool down to 60F or so while unoccupied. But no.

That's building automation.

Hotels go for this stuff, because they have big energy costs and a huge range of occupancy, especially in function rooms.