Quick answer
Insulate exposed pipes, seal cold air leaks, disconnect and drain outdoor lines, and use thermostat‑controlled heat cable on vulnerable runs. During a cold snap, keep the heat on, open sink cabinet doors, and let faucets trickle so water keeps moving.
Why pipes freeze and what to target
Pipes freeze where cold air reaches them or heat can’t. Common hotspots:
- Crawlspaces, basements, and unheated utility rooms
- Exterior wall cavities behind kitchen/bath cabinets
- Garages and attics
- Outdoor spigots and any pipe near vents or poorly sealed rim joists
Focus on supply lines (especially 1/2 in.) and any section with a history of freezing.
Materials and tools
Materials (typical cost range):
- Foam pipe insulation sleeves, 6 ft lengths, 1/2–1 in. ID, 3/8–1 in. wall ($1.50–$4 per length)
- Fiberglass pipe wrap with vapor barrier for bends/irregular runs ($7–$12 per roll)
- Self‑regulating, thermostat‑controlled heat cable, UL‑listed for your pipe material ($2–$4/ft)
- Outdoor faucet covers ($3–$10 each)
- Silicone or acrylic latex caulk; low‑expansion spray foam ($4–$8 tube; $6–$10 can)
- Aluminum foil tape or quality PVC tape; zip ties; pipe clips/hangers ($5–$15 total)
- RV/Marine non‑toxic antifreeze for traps if leaving home vacant ($5–$8/gal)
- Temperature/leak sensors or freeze alarm ($25–$50)
Tools:
- Utility knife, scissors, tape measure
- Caulk gun, drill/driver
- Infrared thermometer (helpful), headlamp
- Safety glasses, gloves
- Non‑contact voltage tester (for outlets powering heat cable)
- Hair dryer for safe thawing (no open flame)
Step‑by‑step: Before the freeze
1) Prioritize the vulnerable runs
- Trace cold‑water lines in unheated or drafty areas. Kitchen and bathroom sinks on exterior walls are prime candidates.
- Use an IR thermometer to spot cold spots and air leaks along rim joists and penetrations.
2) Insulate pipes
- Measure pipe diameters; choose snug‑fit foam sleeves.
- Dry‑fit, then cut to length with a utility knife.
- Snap on with seam facing up; tape seams every 12–18 in. and at joints/bends.
- For tight bends or valves, use fiberglass wrap with a vapor barrier.
3) Seal drafts
- Caulk gaps around pipe penetrations through floors, walls, and sill plates.
- Use low‑expansion spray foam for larger voids at rim joists and band boards.
- Weather‑strip access doors to crawlspaces; keep garage doors closed.
4) Protect outdoor fixtures
- Disconnect hoses. Leaving a hose on is a common cause of burst sillcocks.
- Close interior shutoff to exterior spigots (if present), open the spigot to drain, and cap with a faucet cover.
5) Add heat cable where insulation alone isn’t enough
- Install self‑regulating cable per manufacturer directions on the cold side of the pipe, secure with fiberglass tape or zip ties (not metal wire). Do not overlap.
- Plug into a GFCI‑protected outlet. Use only cable rated for your pipe material and application.
6) Label shutoffs
- Tag the main and fixture shutoffs so you can act fast if a section freezes.
Time: 2–4 hours for a typical basement/crawl; Cost: $50–$200 depending on length and heat cable use.
When a cold snap is forecast
- Keep the thermostat consistent day and night; avoid setback heating.
- Open sink base cabinet doors on exterior walls to let room air in.
- Let vulnerable faucets drip a thin stream, hot and cold if both lines are exposed.
- Run recirculation pumps if your system has one.
Thermostat setting: ≥ 55°F (13°C) if occupied; 60–65°F is safer in severe cold
Drip rate: A steady thread or 1–2 drops/sec at the farthest faucet
Vacant or part‑time homes
If you won’t heat the space or you’ll be away during a deep freeze, winterize:
- Shut off the main water; drain the system by opening all faucets and low‑point drains.
- Blow out lines with an air compressor if available.
Air blow‑out pressure: 30–40 psi for PEX; 40–50 psi for copper/CPVC
- Pour RV/Marine antifreeze into sink, tub, and floor drain traps and toilet bowls/tanks.
- Install a freeze alarm or smart sensor for temperature and leaks.
Safety considerations
- Never use an open flame to thaw or warm pipes. A hair dryer, heat gun on low, or a space heater at a safe distance are safer choices.
- Heat cable: Use UL‑listed, self‑regulating types; match to pipe material; don’t overlap; protect with GFCI; avoid extension cords in damp areas.
- Spray foam is flammable until cured; follow label directions and maintain clearances from heat sources.
- Wear eye/hand protection when cutting insulation and using sealants.
Tips for best results
- Add pipe clips so lines don’t touch cold concrete or exterior sheathing.
- Insulate cold and hot lines—hot lines cool off in long runs and can still freeze.
- Use thicker insulation (3/4–1 in. wall) in very cold regions or windy crawlspaces.
- Map your plumbing with photos before you close access panels.
- Consider a small, thermostatically controlled space heater for well houses or tiny utility rooms—plugged into GFCI, away from combustibles.
Common mistakes
- Leaving garden hoses attached to spigots
- Insulating pipes but ignoring the drafts that chill them
- Using non‑thermostat heat tape or overlapping heat cable
- Setting the thermostat too low at night or when away
- Forgetting pipes over/near garage ceilings and at meter penetrations
When to call a pro
- Repeated freeze issues that point to poor routing—rerouting pipes or adding dedicated heating/circuits is a job for a licensed plumber/electrician.
- Bulged, cracked, or leaking pipes after a freeze—shut off water and call immediately.
- No interior shutoffs for exterior spigots—upgrading to frost‑free sillcocks or adding shutoffs is a good professional project.
- If your heat cable load requires a new GFCI circuit or you’re unsure about electrical capacity.
With a few hours, some insulation, proper sealing, and targeted heat where needed, most homeowners can greatly reduce freeze risk. If you need help choosing pipe insulation sizes or a compatible heat cable, check ToolStash’s pipe insulation and freeze protection categories for the right fit for your piping material and diameter.