The short version
When heat stops during freezing weather, protect people first, identify the heating system and watch for plumbing risk. Do not bypass safety controls or use improvised combustion heaters. For a gas odor, a carbon-monoxide alarm, smoke, fire or sparking, leave the building when appropriate and call 911 or the relevant utility before doing anything else.
Information to collect safely
Identify whether you have a boiler, furnace or heat pump; the fuel; whether the whole home or one zone is cold; the thermostat display; any error code; indoor temperature; backup heat; and whether the equipment also makes hot water.
| Fact | Why it matters |
|---|---|
| Indoor temperature | Sets the clock on when it becomes a plumbing problem too |
| Fuel and power status | Oil/propane systems still need electricity: a common misdiagnosis |
| Occupied or not | An unoccupied property accumulates damage unnoticed |
Protect occupants and plumbing
Arrange a safe warm location if temperature continues falling. Tell the heating professional about exterior-wall or basement plumbing and any vacant rooms. Use only approved backup heat and avoid overloading circuits.
Avoid repeated heating resets
One manufacturer-approved reset may be reasonable when no hazard exists, but repeated resets can hide or worsen a fault. Never bypass a limit, flame safeguard or pressure control.
What to document before service
A clear record helps a professional understand the pattern before changing the system.
- Equipment type, make and model
- Fuel and whether other fuel appliances work
- Thermostat display, settings and batteries
- Exact error code or indicator-light pattern
- Indoor temperature trend and affected zones
- Recent service, outage, fuel delivery or unusual sound
What a complete evaluation should establish
A complete no-heat evaluation should separate thermostat and control trouble from loss of power, fuel delivery, ignition or combustion faults, failed pumps or blowers, frozen condensate, and distribution problems. The technician should also identify any unsafe condition and explain whether the first visit restores heat or only establishes the repair and required part.
After the work
After heat returns, verify that every zone warms, indoor temperature recovers steadily and nearby plumbing remains intact. Keep the service record, part information and any control settings. If a temporary repair was made, confirm the permanent-work date and maintain a written cold-weather plan until the system is reliable.
Common questions
At what indoor temperature can pipes freeze?
There is no single safe threshold. Pipe location, air movement, insulation and outdoor exposure matter, and concealed pipes can be colder than the room.
Should I leave faucets dripping?
That may help in limited situations but does not replace restoring heat, protecting vulnerable piping or addressing a known freeze.
Can I use the oven to heat the house?
No. Ovens and ranges are not safe space heaters and can create fire or carbon-monoxide hazards.
What should I write down before calling a heating company?
The equipment type, make and model, the fuel and whether other fuel appliances work, the thermostat display, settings and batteries, the exact error code or indicator-light pattern, the indoor temperature trend and affected zones, and any recent service, outage, fuel delivery or unusual sound.
Why can an oil or propane system fail when the power is out?
Oil and propane systems still need electricity, and mistaking a power problem for a fuel problem is a common misdiagnosis. Fuel and power status is one of the four facts, with indoor temperature and whether the property is occupied, that decide the urgency.