With no heat, pipes on exterior walls can start freezing within about 6 to 12 hours when it is in the single digits outside, and within a day or more when it is in the 20s. Older, drafty houses cool faster. If the power or heat will be off overnight in a cold snap, shut the main water valve and open faucets to drain the lines. Pipes burst? Call (413) 603-1274.
What decides how fast
- Outside temperature and wind: single digits and wind cool a house fast
- Insulation and drafts: older Chicopee homes with plaster walls and drafty sills cool faster
- Where the pipes run: exterior walls, porches and crawl spaces go first
- House size and sun: a sunny day buys time, a cloudy night does not
Even gas and oil boilers stop in a power outage, because their pumps and controls need electricity. About a third of Chicopee homes heat with electricity outright.
A simple plan for an outage
- First few hours: keep doors closed, open sink cabinets on outside walls, let faucets on cold walls drip.
- If it will last overnight in the teens or colder: shut the main water valve and open faucets to drain the lines.
- Turn off the water heater if the main is off. See how to shut off the main valve.
- Never use a grill, camp stove or generator indoors, including the garage. Carbon monoxide kills.
- When power returns, turn the water back on slowly and watch for leaks.
Rough timelines
There is no exact clock, but these rough examples show how fast it can go once the heat stops:
| House and weather | How long pipes may last |
|---|---|
| Well-insulated house, outside in the 20s | Often a day or more |
| Average older home, outside in the teens | Many hours. Cold spots can freeze overnight |
| Drafty older home, single digits and wind | Pipes in outside walls may freeze within 6 to 12 hours |
| Unheated porch or crawl space pipe | Can freeze within a few hours once below about 20°F |
These are general estimates, not promises. Watch the coldest spot in the house, not the thermostat.
Generators and heat
A portable generator can run a boiler or furnace if it is connected safely through a transfer switch installed by an electrician. Never run a generator inside the house, the basement or an attached garage, and never plug it into a wall outlet. Carbon monoxide from generators kills people every winter. If you do not have a safe way to run the heat, protect the pipes by shutting the main and draining the lines.
Shut the main and drain
If the heat will be off overnight in deep cold, close the main valve, open the lowest faucet and every other tap, and flush toilets once. Empty pipes cannot burst.
Questions
How long does a house stay warm without heat?
A well-insulated house may lose a few degrees an hour at first. An older, drafty one loses heat much faster. Watch an indoor thermometer.
Will a generator keep my boiler running?
A properly installed generator with a transfer switch can. Have an electrician set it up, and keep it outside.
Pipes burst after an outage? Call now
Call (413) 603-1274 now. Locally owned in Chicopee. See oil ran out and pipes froze and what temperature pipes freeze.