A homeowner's cold-weather prep guide

What we mean by cold-weather prep

This isn't about snowstorms or power outages, exactly. It's about the specific small things that go wrong when a house meets sustained sub-freezing temperatures: pipes that split, furnaces that quit, water that finds its way in somewhere new.

The work is mostly preventive, mostly cheap, and mostly forgotten. Here's the short version.

Before the first freeze

These are the items to handle in fall, ideally weeks before you actually need them. If you only do one section of this guide, do this one.

Outdoor pipes

• Disconnect every hose from every faucet. A connected hose holds water in the pipe behind the faucet. That water freezes, expands, and splits the pipe. The split is invisible from outside until you turn the faucet on in spring and discover the wall is wet.
• Shut off and drain exterior lines if you can. Many homes have a shutoff valve inside (basement or crawlspace) for each outdoor faucet. Close it, then open the outside spigot to drain whatever's still in the line.
• Insulate any exposed pipe. Foam pipe sleeves cost a few dollars at the hardware store and slip over the pipe in seconds. Focus on pipes in the garage, crawlspace, attic, and along exterior walls.

Indoor systems

• Service the furnace. Annual maintenance, before you need it. The service catches small failures before they become a no-heat call on the coldest weekend of the year.
• Stock filters. You'll burn through them faster in heavy use. Buy a few.
• Test the CO detectors. Winter is when CO problems happen, because that's when the furnace is running hard and windows are closed.
• Find your main water shutoff and make sure it works. Turn it off, turn it back on. If it's seized, you want to know that on a Saturday afternoon, not at 2 a.m. when a pipe has burst.

Outside

• Trim branches near the house and over the roof. Snow and ice load makes weak branches dangerous.
• Check the roof and gutters one more time. Anything you wanted to fix this year, fix before snow covers it.
• Move snow shovels and salt to where you can actually reach them in a storm. The first storm always happens before people are ready.

The full fall checklist covers more of this in context.

On the day of a cold snap

When the forecast says the low is dropping below 20°F, especially for the first time of the season, a few small things help:

• Open cabinet doors under sinks on exterior walls. Lets warm room air reach the pipes behind.
• Drip the right faucets. Any faucet with pipes in an exterior wall or running through unheated space. A pencil-thin stream is enough. Moving water is much harder to freeze than still water.
• Don't turn the heat way down at night. Setting back a few degrees is fine. Setting back ten degrees, in extreme cold, can let interior wall cavities cool enough that pipes inside them freeze. Hold a normal temperature.
• Open interior doors. Lets warm air circulate to rooms you don't usually heat hard.
• Garage door closed. If pipes run through the garage wall, an open garage on a cold night is a frozen pipe waiting to happen.

If you're traveling during a cold snap:

• Leave the heat on, not way down. 55°F minimum.
• Have somebody check the house once during the cold stretch. If a pipe freezes and bursts while you're gone, the damage compounds for every day nobody finds it.
• Know where the main shutoff is, and tell whoever's checking. Better yet, leave them a key and instructions.

If a pipe actually freezes

Sometimes despite everything, a pipe still freezes. A few things to know:

• Frozen doesn't always mean burst. A pipe can freeze, then thaw, with no damage. The danger is when expanding ice cracks the pipe; the leak shows up when it thaws.
• If a faucet runs slowly or not at all in a sustained cold stretch, that line is likely frozen somewhere. The point of failure is usually wherever the pipe runs through cold space.
• Thaw slowly. Open the faucet first, so water can flow as it melts. Then warm the pipe with a hair dryer, space heater, or warm towels. Do not use an open flame. Do not heat one section blast-hot while the rest is still frozen, which can crack the pipe.
• If a pipe has burst: shut off the main water immediately. Then call a plumber. The flood gets worse every minute the main is on.

This is also the case where you really want to know exactly where your main shutoff is and that it turns. The first time you find it shouldn't be while water is spraying somewhere.

A note on freeze warnings

Most homeowners don't need to be alarmed every time the forecast dips. The actual pattern that causes problems is sustained cold (multiple consecutive nights below freezing, especially the first time in the season when nobody's prepared) or a sudden hard drop from warm weather.

If you want this watched for you so you don't have to refresh the forecast: Stell checks the 10-day forecast for your ZIP from October through December. If a low at or below freezing is coming, you get a single, calm email with the basics. If you've already done the prep, you ignore it. That's the whole thing. No alarms. No daily updates. No call to action that you have to opt out of.

What you don't need to do

A few items that get listed on cold-weather checklists but don't really earn their keep:

• Wrapping every pipe in the house. Focus on pipes in exterior walls, unheated spaces, and obvious cold spots. Insulating a pipe that runs through a heated interior wall is wasted effort.
• Buying generator fuel "just in case." Unless you have a generator and have used it, and your area regularly loses power for days, this is over-prep.
• Sealing every window with plastic. Useful for an old leaky house. Wasted on a modern one. Stand near each window with a hand near the frame: if you can't feel a draft, don't bother.

Most cold-weather problems come from the same handful of things, on the same handful of houses, in the same handful of ways. Handle the obvious ones in fall, do the small things on the coldest days, and the house comes through winter fine.