Frozen water pipes cost more than you could ever save by shutting the heat completely off. Shutting your furnace off saves on your heating bill while you are away from home. But, only as long as the weather does not go below freezing. You need to watch the weather very carefully.
When we lived in Virginia, back when I worked at a shipyard, the management of the townhouse apartment we lived in told us to leave the water running on cold nights. We were warned that the pipes would freeze if we didn’t leave water running.
At first, we didn’t believe them since we were not expecting cold weather like we knew growing up in Michigan. But, we did leave a trickle of water running and sure enough, our neighbors pipes froze and ours didn’t.
Leaving the water running for freeze prevention works, but it is a waste of resources.
I have been trading messages with readers in New York State where the cost of home heating fuel is extremely high and in Minnesota where cold weather is brutal. Both are trying to reduce the money they pay out for home heating.
The objective is saving money
So, we sure don’t want to risk a flood from a frozen and burst water pipe. Then the question becomes, “how low can I go with the thermostat without risking a freeze?”
We all know water freezes at 32F. We also know that at a distance away from the thermostat it may be colder than what the thermostat reads. To me that means 35 is not warm enough for freeze prevention. 40 may work, but 45 in my choice as a minimum. That is a safety margin of 13 degrees. 13 sounds lucky to me!
I suggest you take some temperature readings where your water pipes are located. Then compare them with the thermostat reading. Find out just how many degrees colder it is where pipes are than the thermostat reading.
If your pipes are at a corner of your basement where the temperature is 20 degrees less that the thermostat reading, you better go no lower than 55 on the thermostat. (35 minimum plus 20 = 55)
You can add a heat source right where the pipes are. Space heaters, heat lamps and electric heat cable have all have been used for this. Put the extra heat where it is needed and let the rest of the building cool down more.
I cannot give you an exact best way to prevent freezing because each building or house is different and the weather varies so much.
Just keep in mind the less you heat an empty building the less it costs..until the pipes freeze.
As you work your empty house thermostat setting lower, you may discover another problem. Some thermostats don’t go very low. The old standard was no lower than 55. You may need to get a different thermostat to allow you to get down to 45 or 50.
To maximize your savings now, I recommend you set the thermostat at 62 or lower while you sleep and down to 55 when no one is home for half a day or longer. You should see the savings on your next heating bill.