I just put in an Ecobee thermostat a few weeks ago now and it is Wi-Fi enabled so you can control and monitor it online. If you are looking just to control temps for a house in a cold climate that is a good option. It is not cheap, but it does a great job so far. There are cheaper options out there, but since I haven't used those I can't comment on them.

My BIL had a monitor, wired in to the local fire/police dept, that alerted them if the temperature in their lake/summer cottage (vacation home) went below a certain temp. (no burglar monitor, just the temp) It turned out to be a brilliant idea.

A few years ago, several of the 30+ y/o water pipes in the baseboard heating system finally burst, from either mineral buildup or age, and spewed water all over the house for three days. The monitoring system called his cell phone (He had given them multiple contact #s.) He was out of the country on vacation and had to cut it short.
It was Spring, or the temp would have gone down faster and the alarm would have sounded a day or two earlier with less damage, but at least he had the alarm/monitoring.

The house had to be gutted, and was an excellent opportunity for them to remodel, since he planned to live in it full-time after retirement, which is the case right now. Without the monitor, the house would probably have been 100% ruined from all the water spewing.