First: is anyone in danger?
If you smell gas or a carbon monoxide alarm is sounding, leave the home now and call 911 or your gas utility from outside. Otherwise, do the safe checks below, then call for emergency HVAC service if heat isn't restored.
Everything else on this page assumes there's no gas smell and no CO alarm.
The 15-minute no-heat checklist
- Thermostat: set to HEAT, 5°F above room temperature, fresh batteries.
- Breaker panel: reset a tripped furnace or air handler breaker once only.
- Furnace switch: the light-switch-style switch near the unit is ON.
- Filter: if it's packed with dust, replace it or run without one briefly.
- Furnace door: fully closed so the safety switch engages.
- Outdoor vents and heat pump: clear snow and ice.
- Fuel: propane tank gauge or oil tank level isn't empty.
How fast the house cools
| Outdoor temperature | Rough risk level | Action |
|---|---|---|
| Above 40°F | Low; the house holds heat for many hours | Checks, then book the next available slot |
| 20–40°F | Moderate; the house will be uncomfortable by morning | Call now, protect pipes on exterior walls |
| Below 20°F | High; pipes in exterior walls and crawlspaces at risk | Call now and take pipe precautions |
| Below 0°F or wind chill | Severe | Call now; consider a warm place for vulnerable people |
Keep warm safely while you wait
- Gather everyone in one interior room and close its door
- Close curtains and blinds, especially on north windows
- Roll towels against drafty doors
- Use electric space heaters only plugged into the wall, with 3 ft clearance
- Never use a gas oven, grill, camp stove or generator for heat indoors
- Check on elderly neighbors and pets
What the on-call technician does
Emergency technicians focus on getting heat back safely. They read the furnace's fault code, test the ignition sequence and safeties, and check gas supply.
If the failed part isn't on the truck at night, they may restore partial heat or make the system safe until a return visit.
Before you call, have this ready
Equipment type (gas furnace, heat pump, boiler, oil), the brand if visible, any blinking error code, what you've already checked, and whether anyone at home is elderly, very young or medically vulnerable.
No-heat FAQs
How long can a house go without heat?
It depends on insulation and outdoor temperature. A well-insulated house may stay above 50°F for most of a mild night; an older house in sub-zero wind can drop much faster.
Should I keep resetting the furnace?
No. One reset is reasonable. Repeated resets can mask a safety problem or flood burners with gas.
Next steps
Ready to get it fixed? Call (888) 555-0143 to reach a licensed provider in your area. Related guides:
Busy winter markets: emergency HVAC repair in Texas · emergency HVAC repair in North Dakota · emergency HVAC repair in Minnesota · emergency HVAC repair in New York · emergency HVAC repair in Massachusetts · emergency HVAC repair in Tennessee · all states.