There is a new version of the iSocket coming out shortly and it is on pre-release sale for a few more days (to end of Oct. ??). The device plugs into the electrical socket and notifies you by phone of a power failure. It also has an optional temperature monitor that you can set the range for (monitor heat or A/C as needed). You can communicate with the device interactively by text message from your cell phone (for example, ask if the power is on).
The "new" model that is being released is to be compatible with newer USA 3G/LTE cellular systems (non-GSM systems, which were covered by the older model). It requires the purchase of a separate Sim card, which is a one time purchase and does not require a monthly plan. All the details are on these pages:
Cost is $189 for iSocket 3G, $9 for short temp sensor) more for an extended length one) and from a separate vendor $15 for the SIM card and $15 for a prepaid account that does not expire. Text messages are $.09 so $15 will last a good long time.
I'm going to order one for the RV today and would actually like to have one for the house too!
Land of 10,000 Lakes
2016 Forester MBS 2401R
Nights camped 2016: 29; RV to date: 32