If your insurance requires you to monitor/alert for sub-freezing temps or water, try the products made by Sensatronics in Bow, N.H. (
www.sensatronics.com)
They make monitors for IT (computer) server rooms that can monitor temp/humidity, wetness, open doors, etc. The monitors have built-in mini-computers with their own IP addresses so all you have to do is plug them into an internet outlet (or router) and you can start your remote monitoring. I believe they can also email you or send a text message to alert you of various conditions.
There are also a number of temperature monitoring devices that can send remote alerts on
www.ambientweather.com.
To defend against power outages you can use a surge protector with battery backup (available at Staples and similar stores.) They'll run a computer & monitor for 30 minutes or so (their intended purpose, so you have time to save your work and shut down), but if you only use the battery for modem/router and temp monitoring device it lasts a lot longer, especially if you have a top-of-the-line battery backup.
I do recommend testing the whole system when you're present, just to see exactly how long the battery will last. It can vary.