We have good neighbors. It helps.
Wireless thermometers to houses both sides. Plus a large outdoor circular thermometer that we leave in the window facing neighbors house, just in case.
Another item... A Honeywell Winter Watchman that we picked up for $1 at the resale shop. Plus in to wall plug, and then you plug in any light or other device that turns on when the temperature goes below a preset level. For us 45 degrees.
No phone alert as we turn off internet and the VOIP phone.
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The failsafe, is RV antifreeze in traps and tanks, and we call the town, to have the water turned off at the street. A no charge, mind easing safety precaution.
One more thought... we used to leave thermostat turned down to 55 degrees, but have found it safe to reduce that to 45 degrees.
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Even with the water turned off, a learning experience:
In Florida, in our mfg home, the shut off at the street... a bronze gate valve, seeped, allowing a build up in pressure in the home. The plastic fitting on the riser to the toilet tank, cracked with resultant flood and $7K damage. That fitting has a history of weakness caused by the flouride in the water. Since then (8 years ago) we had the supply pipes throughout the house replaced with braided metal and metal connectors and individual shut offs.... A good item to check... and a relatively cheap fix.