About 4 years ago I bemoaned the heating in our house. It turns out that providing you're willing to connect things to the internet it's super easy. It was probably possible the time I wrote the post if you're okay with the internet.
Simply use Tado°! Replace your thermostat with theirs, connect the internet bridge to your network and you've a minimal setup. At this point through the app you can define arbitrarily complicated heating schedules, have it adapt to the weather, detect open windows by drops in temperature, reduce the heating if you leave the house.
This is great but didn't solve the problem that our thermostat lives next to the front door in the coldest part of the house. The eyeballing of what temperature that zone should be to give comfortable results elsewhere continues but more accurate and on a schedule.
The evening we installed their wired thermostat we ordered four of their radiator valves doodads. They replace the dial on your radiators, connect to the network, control the flow into the radiator, and measure temperature and humidity. Now you can set those arbitrary schedules on a room by room basis. Now the boiler fires up when a room needs to be warmed and it doesn't overheat any of the other rooms. Golden.
The installation of all these was very simple and the app walks you through it all. No complaints there.
We have a couple of radiators that don't currently have valves (think bathroom style ones). To smarten these, we'll need to get a plumber to add them in which involved draining the system. A future job.
All in all, I'm very happy with the solution. The Tado being based in Germany gives me some hope about their privacy policies. They’ve also been around for more than a decade and aren’t owned by Google so I’ve some faith that they won’t just kill the product. Various features require connection to the outside world which is a bit funky but I’m coming around to the idea after having some smart bulbs for a year.
 - It turns out a friend was already doing this back then.