How to Insulate Pipes for Winter (2026) — Step-by-Step Guide

Please note: Product information in this guide is based on our research at time of writing and are subject to change. Always follow manufacturer instructions and consult a licensed plumber if you are unsure about any aspect of your home’s plumbing.

Introduction

Frozen pipes are one of the most disruptive winter plumbing emergencies. Water expands as it freezes, and that expansion can crack or burst a pipe — metal or plastic. The resulting water damage can be costly, and drying out walls, replacing flooring and dealing with mold add to it. Insulating exposed pipes is one of the steps that reduces the risk, but insulation only slows heat loss: it does not guarantee that a pipe will not freeze.

In this guide we cover three methods of pipe protection — foam pipe insulation (the common approach for pipes in unheated areas), outdoor faucet preparation and covers, and electric heat cable for pipes in very cold unheated spaces. Whether you’re winterizing a new home or finally getting around to a task you’ve put off for years, this guide covers the main steps, and points you to the manufacturer’s instructions where the details depend on the product.

For our recommendations on the best foam products available, see our guide to the best pipe insulation. And if you’ve already experienced a pipe failure, our guide to the best pipe repair clamps covers your emergency repair options.

Why Pipes Freeze and Burst

Understanding why pipes burst helps you know where to focus your insulation efforts. Water expands as it freezes. Inside a rigid pipe that expansion has nowhere to go, so pressure builds and can crack or split the pipe. The damage often becomes obvious only when the ice thaws and water pours out.

The freezing doesn’t always happen where you expect. A pipe often freezes in one location — an unheated basement, a crawl space, an exterior wall cavity — but the burst occurs somewhere else entirely when pressure builds and finds the weakest point. This is why the resulting water damage can be so extensive before you even know there’s a problem.

The most vulnerable pipes in any home are those exposed to outdoor temperatures or located in spaces that receive no heating:

• Pipes in unheated basements, crawl spaces, and attics
• Pipes running through exterior walls
• Water supply lines in garages and outbuildings
• Outdoor hose bibs and spigots
• Pipes near vents or drafty areas where cold air enters the home

Which Pipes Need Insulating

Not every pipe in your home is at risk — pipes inside heated interior walls and in climate-controlled spaces rarely freeze. The goal is to identify the vulnerable runs and focus your effort there. Here’s a checklist of the areas to prioritize:

Unheated Basements and Crawl Spaces

The Red Cross lists water supply pipes in unheated interior areas such as basements and crawl spaces among those that freeze most frequently. Any supply lines running through these areas — especially those close to the foundation wall — are worth insulating. Even a partially heated basement can develop cold spots near vents, windows, or foundation penetrations.

Pipes in Exterior Walls

Pipes routed through exterior walls are particularly vulnerable because the wall cavity can drop close to outside temperature on cold nights. Check under bathroom sinks on outside walls, kitchen plumbing on exterior walls, and any utility pipes that run through attached garages.

Garages and Outbuildings

If your garage has a water supply line — for a utility sink, washing machine, or hose bib — insulate it thoroughly. Garages receive no heating and can reach outdoor temperatures even when the garage door is closed.

Outdoor Hose Bibs and Spigots

Every outdoor faucet needs attention before winter, and the right steps depend on the type: a conventional hose bib, or a frost-proof (freezeless) model. The Red Cross lists outdoor hose bibs among the pipes that freeze most frequently. Step 3 explains both, and tells you what to follow for your own faucet.

Tools & Materials Needed

Pipe insulation requires minimal tools and is available at any hardware store. Here’s everything to have on hand before you start:

Materials

• Foam pipe insulation — pre-slit polyethylene or foam rubber tubes made to fit the size and material of the pipe you are covering (see Step 1). See our guide to the best pipe insulation products for our top picks
• Pipe insulation tape or zip ties — to secure foam at joints, bends, and regular intervals along straight runs
• Electric heat cable (optional) — a UL-listed product made for water pipes, for pipes in very cold unheated spaces where foam insulation alone may not be enough. Buy the cable your pipe material, pipe size and location call for, and keep its instructions (see Step 4)
• Outdoor faucet covers — dome-shaped foam covers that fit over exterior spigots and hose bibs

Tools

• Measuring tape — to measure pipe outside diameter and total run lengths
• Utility knife or sharp scissors — to cut foam tubes to length and make miter cuts at pipe bends
• Marker or pencil — to mark cut lines on foam before cutting
• Flashlight or headlamp — essential for working in dark crawl spaces and basements

Step 1 — Measure and Cut Foam Insulation

Before buying materials, measure the pipes you plan to insulate. Pipes are sold by a nominal size, which is a name and not the measured outside diameter, and the outside diameter of a pipe with the same nominal size differs between materials such as copper, PEX, CPVC, PVC and galvanized steel. Pipe insulation is made to fit specific pipe sizes and materials, so measure the pipe you actually have and choose insulation made for it. Insulation that is too small will not close fully around the pipe, and insulation that is too large will not fit snugly.

Measuring Pipe Diameter

Find the outside diameter of each pipe, which is the part the insulation has to fit:

1. Identify the pipe material — copper, PEX, CPVC, PVC and galvanized steel pipe of the same nominal size can have different outside diameters
2. Measure the outside diameter — wrap a tape measure around the pipe to get the circumference and divide by 3.14, or measure across the pipe with a ruler or calipers
3. Match it to the insulation’s stated fit — read the insulation’s label or sizing chart for the pipe size and material it is made for, and choose the one that matches your pipe’s outside diameter, as the Building America Solution Center advises (match the pipe’s outside diameter to the sleeve’s inside diameter for a snug fit)

If you are unsure, take a short sample length of the pipe to your hardware store for a direct match.

Cutting Foam to Length

Measure the total length of each pipe run and allow extra for waste at joints and bends. Cut foam tube sections to length with a utility knife using a straight edge as a guide. For pipe bends and elbows, cut each adjoining piece of foam at a 45-degree miter angle so the two pieces meet snugly at the curve without leaving a gap.

Step 2 — Install Foam Pipe Insulation

Foam pipe insulation comes pre-slit lengthwise, making installation straightforward — no special tools are needed to fit it to the pipe. The key is ensuring continuous coverage with no gaps, which is where cold air enters and insulation effectiveness drops sharply.

Installing on Straight Runs

1. Open the foam tube along its slit and fit it over the pipe, with the slit turned the way the insulation maker directs (the Building America Solution Center’s general guidance is slit facing down)
2. Close it completely around the pipe with no gap at the seam
3. Butt each piece end-to-end with no gaps between sections — even a short gap leaves the pipe uncovered at that point
4. Secure and seal it as the maker directs; the Building America Solution Center suggests fastening about every 1 to 2 feet and taping seams with acrylic or aluminum foil tape
5. At pipe fittings and valves, cut the foam neatly to fit and tape it firmly around the fitting on both sides

Installing at Bends and Elbows

Bends are the trickiest part of the job — a poor fit here creates a gap that undermines the protection of the whole run:

1. Cut two pieces of foam at 45-degree miter angles so they meet squarely at the bend
2. Snap each piece over its section of pipe and press the mitered ends together firmly
3. Wrap the joint tightly with insulation tape to hold the two pieces in firm contact

For tighter bends, make multiple shallow cuts on the inside curve of the foam so it can flex around the elbow without buckling or creating a gap on the outside of the curve.

Step 3 — Insulate Outdoor Pipes and Spigots

Outdoor faucets are among the pipes the Red Cross lists as freezing most frequently, so they come first. Complete this step before the first hard freeze of the season. The steps depend on the type of faucet, so look at yours first: a conventional hose bib, usually supplied by a pipe that may have its own inside valve, or a frost-proof (freezeless) hydrant, a long-stem design meant to drain itself when it is shut off. If you are not sure which you have, or if the faucet has no inside valve you can find, ask a plumber before winterizing it.

Preparing Outdoor Faucets for Winter

For every outdoor faucet: disconnect all garden hoses, drain them and store them for the winter, as the Red Cross advises.

Conventional hose bibs with an inside shutoff valve

The Red Cross procedure for a hose bib supplied through an inside valve is:

1. Close the inside valve that supplies the outdoor hose bib — follow the valve’s own handle type (a quarter-turn handle closes differently from a wheel handle) until it is fully closed
2. Open the outside hose bib to let the water drain
3. Leave the outside hose bib open. The Red Cross says to keep the outside valve open so that any water left in the pipe can expand without breaking it

Do not close the outside faucet after draining it. If your outdoor faucet has no inside valve, these steps do not apply as written; follow the faucet manufacturer’s instructions or ask a plumber.

Frost-proof (freezeless) hydrants

A frost-proof hydrant is designed to drain itself when it is shut off, but only if it was installed and is used as its manufacturer specifies. Woodford’s installation sheets for its Models 65, 67 and 68, for example, say that the inlet must be in a warm interior area, that the tube must be installed with the slope shown for the model, that the air vent in the stem must not be plugged, and that you close and drain the hydrant by turning the stem fully closed until water drains from the drain hole; they warn that hydrants installed or operated improperly may freeze and burst. Follow the instructions for your own model, which may differ, and keep hoses and attachments off it in cold weather as the Red Cross advises.

Fitting Outdoor Faucet Covers

Outdoor faucet covers are dome-shaped foam covers with an elastic or drawcord seal that fits over the faucet, trapping an insulating air pocket around the bib. Fit one over each outdoor faucet after you have finished the steps above. A cover adds insulation but does not replace draining the line or following the faucet manufacturer’s instructions.

For faucets on particularly exposed walls or in regions with severe winters, you can also wrap the short section of pipe between the exterior wall and the bib with foam pipe insulation for an additional layer of protection.

Step 4 — Install Heat Tape for Extreme Cold

Electric heat cable (sold as heat tape or heat cable) is meant for pipes in very cold unheated spaces where foam insulation alone may not be enough. Unlike foam, which only slows heat loss, heat cable adds heat to the pipe. The Red Cross suggests UL-listed heat tape or heat cable on exposed water pipes, and the Building America Solution Center suggests considering temperature sensor-controlled electric heat tape in freezing climates on pipes in uninsulated or unconditioned basements, crawl spaces, attics or exterior walls.

Follow Your Own Cable’s Instructions

Heat cable is also an electrical and fire risk if it is the wrong product or is installed wrongly, and the instructions differ from product to product. Easy Heat’s HB cable, for example, is for metal pipes only and must never overlap itself, while other cables allow different pipe materials and routing. This guide therefore does not give a single method. Buy a UL-listed cable made for your pipe material, size and location, and install it exactly as the sheet that comes with it says, or the manufacturer’s current sheet for your model. In that sheet, check:

• Pipe materials and places it may be used — metal, plastic or both, indoors or outdoors, and where it must not go (inside walls, floors, buried, or on drain lines and hoses)
• Routing and overlap — whether it must lie straight or may be spiraled, the length or spacing chart for your pipe size, and whether it may touch or cross itself; the U.S. Consumer Product Safety Commission’s guidance says a heat tape should not be lapped over itself unless the manufacturer’s instructions specifically permit it
• Insulation — whether it must, may or must not be covered, with which material and how thick; the CPSC guidance says to use only non-flammable insulation such as fibrous glass if the cable is insulated, and never to cover it unless the manufacturer advises
• Fastening — the type and temperature rating of the tape or ties to use, and what not to use
• Electrical protection — the outlet and circuit it needs, ground-fault (GFCI) protection, thermostats or pilot lights, and whether an extension cord is allowed
• Testing — how to confirm it works before cold weather, using the method in your instructions

Check It Every Autumn

The CPSC guidance advises inspecting heat tapes and cables in the fall: replace one whose plastic covering is damaged or cracked, and if you find bare wires or charring, install a new heat cable. If you are not sure the cable is suitable or installed correctly, ask a licensed electrician or plumber.

Extra Winter Pipe Protection Tips

Pipe insulation does much of the work, and these additional habits add to your plumbing’s protection during a hard winter.

• Keep your home heated to at least 55°F (13°C) even when away — the Red Cross advises keeping the heat no lower than 55°F. Turning the thermostat off entirely while traveling leaves pipes exposed to the cold
• Open cabinet doors under sinks on exterior walls during cold nights — this allows warm interior air to circulate around the pipes and prevents cold spots in otherwise insulated wall cavities
• Let cold water drip from a faucet served by exposed pipes during very cold weather — the Red Cross advises this when it is very cold outside
• Know where your main water shutoff valve is located — and make sure every adult in your household knows too, so the water can be shut off quickly if a pipe bursts or leaks
• Check your insulation at the start of each winter season — foam can shift, split, or slip off bends over time. A 15-minute visual walkthrough each autumn confirms your protection is still fully in place before temperatures drop

If a pipe fails despite your precautions, see our guides to the best pipe repair kits and best pipe repair clamps for the fastest emergency repair options while you wait for a plumber.

Frequently Asked Questions

Q: At what temperature do pipes freeze?

There is no single outdoor temperature at which every pipe freezes. It depends on how exposed the pipe is, whether it is insulated, wind and drafts, and how long the cold lasts. The American Red Cross lists the pipes that freeze most frequently — pipes exposed to severe cold such as outdoor hose bibs, supply pipes in unheated interior areas, and pipes against poorly insulated exterior walls — and advises protecting pipes before the onset of cold weather and, when it is very cold outside, letting cold water drip from a faucet served by exposed pipes. Its guidance does not give a temperature threshold.

Q: How much does pipe insulation cost?

The cost depends on how many feet of pipe you are insulating, the pipe sizes and materials, and the products you choose, so no single figure fits every home. Measure your pipe runs first (Step 1), add up the lengths, and compare prices for the sizes you need. Outdoor faucet covers and heat cable are separate purchases; heat cable varies with its type and length.

Q: Can I insulate pipes myself or do I need a plumber?

Fitting foam pipe insulation and outdoor faucet covers is a task many homeowners handle themselves; how long it takes depends on how many pipes need attention and how easy they are to reach. Installing heat cable also involves electrical requirements, so follow the cable manufacturer’s instructions closely, including any ground-fault protection requirement, and have an electrician check anything you are unsure of. You only need a plumber if pipes are already frozen or have burst, or if they run through locations that are genuinely inaccessible without professional assessment.

Q: What do I do if my pipes freeze?

If you turn on a tap on a cold morning and get little or no water, a pipe may have frozen. What to do depends on whether you only suspect freezing or can see signs of a leak.

Suspected freezing (no sign of a leak): keep the faucet open while you thaw the pipe, as the Red Cross advises, so water can flow as the ice melts. Apply heat to the section you think is frozen with a heating pad, a hair dryer, a space heater kept away from anything flammable, or hot towels. Never use an open flame. Check your other faucets too, since more than one pipe may be affected. If you cannot find the frozen section or cannot thaw it, call a licensed plumber.

Confirmed leak, burst pipe or cracking sounds: shut off the main water supply valve and call a licensed plumber.

Conclusion — Prepare Before the Cold Arrives

Insulating exposed pipes and preparing outdoor faucets before the cold arrives reduces the risk of a burst pipe, though no method guarantees a pipe will not freeze. The steps that matter most are to protect the pipes the Red Cross lists as freezing most often and to follow the instructions that come with your faucet, insulation and any heat cable.

• Match the insulation to your pipe — measure the actual outside diameter and choose insulation made for that pipe size and material
• Focus on the exposed pipes first — outdoor faucets, supply pipes in unheated basements, crawl spaces, attics, garages and cabinets, and pipes against poorly insulated exterior walls
• Prepare outdoor faucets for their type — hoses off, then the conventional-bib or frost-proof procedure that applies to yours
• Use heat cable only as its manufacturer’s instructions direct — pipe material, routing, overlap, insulation, fastening, electrical protection and testing all depend on the product
• Back it up with simple habits — keeping the heat on when you travel, dripping a faucet during very cold weather, and knowing where your main shutoff valve is

To help choose foam products for this job, see our full guide to the best pipe insulation for US homeowners. For the wider picture on keeping pipes from freezing, see our complete winter freeze-protection guide.