Protecting Against Frozen Pipes

Frozen and burst pipes are a recurring New Hampshire winter problem. Risk rises in exterior walls, crawlspaces, garages, poorly heated rooms, and other places where cold air reaches the plumbing. A.J. LeBlanc Heating's plumbers help homeowners find vulnerable piping, improve protection, and respond when a line freezes or breaks.

What causes pipes to freeze in a NH home

Frozen pipes happen when three conditions combine:

• Pipes located in unconditioned or poorly heated space (basements, crawlspaces, exterior walls, garages, attics)
• Little to no flow through the pipe (idle pipes freeze faster than active ones)
• Sustained sub-freezing temperatures, especially below 0°F for extended periods

The risk increases dramatically when the home's heating system is set far below normal (vacation setback), a wood stove or pellet stove is used as the primary heat (which can keep the central thermostat satisfied while rooms far from the stove run much colder), or a power outage shuts off the primary heat.

Prevention before a cold snap

Keep heat in areas with plumbing

During cold weather, keep occupied areas with plumbing at 60°F or warmer and maintain heat in vulnerable spaces. If the home will be vacant, the Red Cross says not to set the thermostat below 55°F. A higher setting may be appropriate where piping runs through unusually cold areas. Check the requirements in the homeowner's insurance policy as well.

Promote airflow to vulnerable plumbing

• Open cabinet doors under sinks on exterior walls so room air can reach the pipes.
• Open interior doors to spread heat through the home, especially to rooms over garages or near exterior corners.
• Keep garage doors closed if there is plumbing or heating equipment in the garage.

Add insulation to at-risk pipes

• Foam pipe insulation (a few dollars per length, tool-free install) on pipes in unheated basements, crawlspaces, and along exterior walls.
• Heat tape (electric warming cable) on the most vulnerable runs that cannot be insulated practically.
• Seal air leaks where pipes pass through exterior walls or into unheated spaces.

Let cold-vulnerable faucets drip

If a fixture has frozen in the past, or sits on an exterior wall, let it drip slowly during the worst overnight cold. Moving water is harder to freeze than standing water. A pencil-lead-thin stream is sufficient.

What to do when a pipe freezes

Find the frozen section

The frozen section is typically the run where water flow has stopped at a fixture. Common locations: under sinks on exterior walls, in basement ceilings near rim joists, in crawlspaces, along exterior walls in finished basements.

Thaw it carefully

• Open the faucet served by the frozen pipe so meltwater has somewhere to go.
• Apply heat gently with a hair dryer, heating pad, or space heater. Work from the faucet side toward the frozen section.
• Never use an open flame (torch, propane heater). Plumbing fires are a real and dangerous risk.
• Once water starts flowing, leave the faucet open at a small trickle until the pipe is fully thawed and you have addressed the cause.

What to do when a pipe bursts

A burst pipe is a real emergency. Act in this order:

1. Shut off the main water supply at the meter or where the line enters the home. Every household member should know where this is located.
2. Shut off the heating system if a hydronic (boiler) pipe burst. This stops circulation and reduces the leak rate. For zone-specific leaks, you can shut off just the affected zone.
3. Turn off electricity to areas where water has reached outlets or equipment.
4. Open faucets to relieve pressure and drain remaining water.
5. Call a licensed plumber. A.J. LeBlanc Heating provides 24/7 emergency service across southern NH.
6. Call your insurance carrier if there is significant water damage.

Schedule a winter readiness inspection

If you have had frozen pipes before, your home has known cold spots, or you simply want a plumber to look at vulnerable plumbing before the next cold snap, contact A.J. LeBlanc Heating. For 24/7 emergency service, call 603-623-0412. Serving New Hampshire families since 1928.

Frequently Asked Questions

At what temperature do pipes freeze?

Water can freeze whenever the pipe itself reaches freezing conditions. How quickly that happens depends on air leakage, insulation, pipe location, water movement, and the duration of the cold. Treat any known cold spot or previously frozen line as vulnerable instead of waiting for one outdoor-temperature threshold.

Should I leave faucets dripping during a cold snap?

For at-risk fixtures (exterior walls, history of freezing), yes. A pencil-lead stream of cold water is enough to prevent freezing. Hot water taps benefit too.

Can I use a torch to thaw a frozen pipe?

No. Plumbing fires from torches are a real risk, especially in older walls with combustible insulation, paper-wrapped pipes, or wood framing. Use a hair dryer, heating pad, space heater, or call a plumber.

How do I shut off my main water supply?

The main shut-off is typically located where the water service enters the home, often near the water meter or pressure tank (for well systems). Locate yours before an emergency happens. If you cannot find it, your plumber can show you on the next service visit.

Will my insurance cover a burst pipe?

Coverage and the homeowner's duty to maintain heat or shut off water come from the individual policy. Contact the insurer before an extended winter absence and after significant damage.