Insulating pipes can prevent freezing.
Water pipes in your home can burst when freezing temperatures create ice in the pipes. As ice continues to form, it acts as a piston and subjects water trapped between the blockage and your faucet to tremendous pressure, causing pipes to spring leaks.
Ironically, burst pipes are a real problem in the South, where building practices there may not adequately protect pipes from the unseasonably cold temperatures encountered this winter. Pipes that snake through attics, crawl spaces, or exterior walls—especially poorly insulated pipes—are most likely to freeze.
You probably have a frozen pipe if the faucet or appliance relying on it isn't getting flowing water. A temporary solution is to allow the faucet to drip slowly. While this may not prevent an ice blockage, it can prevent the pressure from building up and possibly bursting your pipes. If the faucet stops dripping, don't close it—the pressure still may need to be released.
“You want the smallest drip rate that will provide pressure relief. A slow trickle is overkill; just make sure there is a consistent dripping,” says Bill Rose, a research architect at the University of Illinois' Building Research Center. “If you have a single-lever faucet setting, provide pressure relief to hot and cold pipes by leaving the setting in the middle so water can drip out from both the hot and cold water supply pipes." As for outside spigots, turn off the water to these lines and drain them. Don't leave a hose attached to the spigot.
“Basically, water pipes should be within an insulated space if you’re anywhere north of the Rio Grande,” Rose says. “Everyone knows that water freezes at 32°F, but the process that leads to burst pipes needs persistently lower temperatures, and every case is different. We have reported that pipes begin to freeze when the temperature approached 20°F, but this number was derived from tests at our field laboratory in Illinois that had an eight-foot section of water pipe running through an uninsulated attic. If the length of pipe was longer than eight feet, an ice blockage would have been more likely. Ice formation would also depend on the thermal conductivity of the pipe materials and the insulation."
Where you can, cover water pipes with insulation. If freezes are common where you live, consider warming the problem pipes with electric heat tape.
“Often we think of putting insulation on the pipe to protect it from the freezing air on the outside; this does have an effect, but the water must be able to give off heat to become ice,” Rose says. “Insulation can delay this process and prevent ruptures."
If you go on vacation, do not turn your heat totally off—leave it set to around 55°F. But Rose advises caution here also. "Fifty-five degrees is a broad rule of thumb, just like the 20°F mark at which pipes freeze. It may work in a house with a basement but not one with a crawlspace." The ideal solution if you're leaving a house unoccupied during cold weather, according to Rose, is to call a plumber get his advice. And if you're going away for a long period, consider learning how to fully drain your system.
"We’re moving into an era where energy will be scarcer and more intermittent, and it’s good for consumer to get into any habit that will let their homes withstand occasions when they can’t keep heat in the house, such as when the furnace goes out," Rose adds. —Gian Trotta
Essential information: See our recent Weekend Projects on insulating water pipes and weatherizing your attic.