How To Prevent Pipe Freezing in Power Outage Using Battery Backup Only
Pipe Freezing in Power Outage – How To Prevent with Battery Back Up Only
‘Weekend only Single family house
Climate Zone 6
What system(s) and components would you suggest to prevent pipe freezing when we are not there during a potential multi-day power outage, considering the following:
Electric only house
Well pump
Septic pump
Grinder pump
heat pump with ducted air handler
Well insulated
It seems any number of battery back up systems (without solar) can handle everything ‘except’ hvac.
IDEA: What about a small, manually operated oil filled or other electric heater set to lowest temperature, and placed in the below grade mechanical room, where the water heater, well tank, PEX lines, and copper lines to kitchen sink, are located.
If we leave during the week, close well tank supply valve, leave all plumbing fixtures open, will this small heater be enough to keep this area warm enough? I realize it may be impossible to calculate how long this set up would last. Do we have to drain the tanked hot water heater each time?
Thanks
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Replies
17whippoorwill,
Almost all the damage occurs due to pressure building up in the lines when there is no outlet, as opposed to the expansion of the water as it becomes ice, so opening up valves or faucets to relieve pressure goes a long way to eliminating the risk.
If you are able to isolate the plumbing in a single well insulated space, a very small direct vent propane heater can keep it warm enough. You can get one that doesn't require power, or if you have battery back-up, use it to run the controls, which draw very little.
You may find this excellent blog by Jon Harrod useful: https://www.greenbuildingadvisor.com/article/why-pipes-freeze-and-how-to-prevent-it
You might find this video interesting.
https://www.youtube.com/watch?v=gNKTZosL6d8
Very low cost Chinese diesel heaters designed for RVs and automobiles requires very little electricity.
Walta
Walta
Always remember to turn off the breaker to your hot water tank if you shut off the water supply valve. Not a bad idea to put a reminder note at the water supply valve.
I've thought about this issue a few times before but don't have a great answer. I've been thinking about it for more extreme scenarios.
My specific questions are:
1) If you partially drain the water pipes (e.g. by releasing the pressure,) do you facilitate the growth of bacteria in those pipes? E.g. is it better or worse (or the same) to leave a house unoccupied with the water pipes full of water (no air) or half full of water (some air).
2) Should it be possible to set up an air-purge system for water systems in remote vacation homes to blow out all the pipes before winter (like people do for irrigation systems or in some RVs.) Similar to the above concerns, if the pipes, mixing valves, etc, are left in a state where they are moist..(not fully dried out,) could that facilitate growth of bad stuff? Is there a reasonable way to safely purge the system with air? (clean air - no oil, dry air, etc.)
3) Should people consider setting up remote vacation homes in cold areas with a system that allows them to easily fill the pipes with RV water system antifreeze (very different from the toxic antifreeze used in engines.) https://www.thervgeeks.com/is-rv-antifreeze-toxic/
In your situation, it sounds like a supplementary heating system based on propane may be the right answer. If you only need to keep the pipes above freezing for a few days, then you won't need a massive tank of propane.
Do you have a sense for how warm you need the interior of the house to be and how much area you need to heat?
Using Celsius... If you have a pipe in the middle of an exterior insulated wall and it is -20 outside, then you will need to keep the temperature inside at greater than 20 degrees. That is a lot worse than a scenario where the pipe is an interior wall so you just need to keep the temperature above 0.
One final consideration.... You might be able to use heating cables for small sections of pipe that are most at risk (e.g. where the supply pipe enters your house through an outside wall.)
Michael Maines says the Passive Houses he designed in New England don't ever freeze when the power goes out. I hope he chimes in.
Interesting. Meaning that the solar gain from windows and thermal gain from the earth through the basement is enough to keep the temperature above freezing?
Plus occupant activity.
DC,
I guess meaning they might not function that way if no one is there.
I have a seasonal house, for 20 years I've drained the pipes about three times a year.
I haven't noticed anything with bacteria, and I do test the water. What I do notice is that over time sludge tends to build up on the inside of pipes. When the pipes are drained the sludge tends to dry out and loosen, and when you turn the water back on there's crud in your water. So I take all the aerators off the faucets when I drain, and I flush the pipes until the water runs clear when I turn it back on again. I think if there were bacteria that would blow most of it out.
I blow my pipes out with compressed air when it's time to drain them. I've fitted valves to simplify the process, but it takes about an hour to do the whole house, 3-1/2 baths, kitchen and laundry.
This is interesting. I'm going to keep this in mind if I ever build a seasonal escape in the mountains.
One year I tried filling the pipes with RV antifreeze. Yes, it's non-toxic, but it has a taste and smell. It took a long, long time for the taste and smell to go away.
Good to know. I'm pretty picky about that.
As a cheap addition to whatever other freeze protection you may utilize, I have liked using a freeze miser on the hose bib that is the farthest/lowest section of plumbing on my house. It starts dripping as the temperature drops below 37F, increasing as it gets colder, bringing warmer water through to keep it from freezing since my water supply stays above 50F. It could also serve to depressurize lines if the pump is off and the water is near freezing. It doesn't rely on electricity, just a sort of thermal wax that shrinks as it freezes and expands as it warms. You can test it by throwing it in the freezer for an hour and then connecting it. My plumbing runs through a conditioned crawl space so hopefully freezing will be a non issue but I like the extra security and have used one for 3 winters now.
https://www.freezemiser.com/pages/how-it-works
This isn't really a question that can be answered from theory.
You can buy wifi temperature sensors for less than $20. Put a bunch around the house. If you also get a wifi thermostat you can turn the heat off and get a feel for how fast the temperature drops and how low it goes.
Just turning the well off and cracking a faucet depressurizes the plumbing and gives some protection. I would turn the well off when nobody's there as best practice anyway.