Remote home monitoring / Smart home systems like Google Nest

[venomtail]

Firstly, do any of you have smart homes and do you recommend then? I ask because...

 

... I will be renovating my house soon. I was hoping to put systems in place that allow me to remotely monitor the inside temperature, Smoke/CO2 alarms and as a stretch goal, remotely see energy, water and gas use. Wanted the system to be capable of allowing me to check in on it remotely because I myself travel, might be away from my house for a 2, 3 months and I'd like to check up on it to see how well it's doing. If it's a really rough winter I might get worried, what if the temperature I set it too low, etc. 

 

So I'm looking at solutions, best if it's an all in one. So far I've come across Google Nest and Bosch Smart Home ecosystems. Does anyone have experience with any and have recommendations? Bosch seems to offer mode gadgets, even radiator control but I've no idea how well that'd work as the house is old, using chunky thick cast iron radiators so no idea if connections would fit. Google Nest has less features but seems to be a powerhouse in the things they do have. On a surface level, if they offer it, it's the best of the best?

 

Then about the smart home monitoring, thermostats and so on. How exactly the work and their setup? Not sure if relevant but I've got about a 20 year old Junkers gas boiler. It has a psuedo smart thermometer attached, somehow from years ago.

 

The thing that complicated monitoring and accounts is, who will have access to it? From time to time I allow a relative to stay at the house for a few months at least. I remember one of them had my house be a really convenient place to stay whilst learning at uni. Times are hard now as well, even considering allowing people to rent the place whilst I'm away like on AirBnB. If I had a Nest or other, how would accounts work? I'd still like to monitor the place but of course still give them the option of changing the temperature and so on to their likings as they're paying, without messing or peeping in on their lives. Does google Nest have like an Owner -> guest mode, same as just about all phones, TV's, PC's, game accounts and so on?

 

In terms of remote monitoring, the only option is a dedicated wifi connection all devices are connected to? Just in case there are alternatives I am not aware of.

 

And yea last solution that I fear will likely need to be bespoke is the remote meter readings. Don't think anyone offers at least a mass market solution right?