No heat at home: safe checks, warning signs, and next steps

A carbon monoxide alarm needs emergency action

If a carbon monoxide alarm sounds, move everyone outside to fresh air and call emergency services. Do not stay inside looking for the source or return until responders say it is safe. Carbon monoxide cannot be identified by smell. Never use a generator, grill, or camping stove indoors to heat the home.

CPSC — Carbon monoxide fact sheet · Source checked 2026-09-06

Check the thermostat before investigating equipment

If there is no sign of an immediate hazard, confirm Heat mode and set the temperature above the current room reading. Check an accessible thermostat display and replace user-replaceable batteries only as its instructions allow. A fan setting can circulate air even when no heat is being produced.

For a forced-air system, inspect an accessible filter with the system off and follow the manufacturer’s replacement instructions. Clear furniture from supply and return grilles. Do not remove burner panels, bypass a safety switch, relight equipment without qualified help, or repeatedly reset a fault.

Carrier — Furnace not turning on · Source checked 2026-09-06

Identify what heats the home

You do not need the technical model name to request help. Describe how warmth reaches the rooms and any fuel type you know.

Use heat-pump repair, boiler repair, or mini-split repair when that matches your equipment. Choose a general service request if unsure.

Know when to stop and get help

If you smell gas, leave the building without operating switches or attempting a repair; call your gas utility’s emergency line or emergency services from outside. Keep away from smoke, sparking, or water near electrical equipment. An online request is not an emergency response channel.

If the home is getting too cold to remain safely, arrange a warm place to stay while seeking service. Keep equipment faults and any temporary heating arrangements separate: do not improvise a combustion heat source inside.

PG&E — Gas leak safety · Source checked 2026-09-06

Record the pattern, not a guessed diagnosis

Before the visit, note the time heat stopped, thermostat setting and room reading, whether fans run, and whether the problem affects one room, one zone, or the whole home. Write down error messages visible without opening equipment.

For example: “All radiators are cold, both zone thermostats are calling for heat, and the problem started this morning.” That tells the provider more than “the boiler is broken.” For a furnace, distinguish no air movement from air that never warms.

What a useful heating assessment should explain

Ask the provider to connect the observed failure with the repair recommendation, and to distinguish a safety concern from a comfort or maintenance issue.

1. What was tested and what fault was found?
2. What work is required before the system can operate, and why?
3. What does the written repair price include, including diagnostic charges?
4. Do parts or labor warranties change your out-of-pocket cost?
5. What checks will confirm that the repair restored proper operation?

If replacement is recommended, request a separately scoped option and the reason repair is not the preferred approach. Use the repair-or-replace guide to compare the costs over a consistent period.

Common question

Why is the fan running without heat?

Fan operation does not establish that the heating equipment is producing heat. Check the thermostat mode and fan setting, then record whether air ever warms and whether the unit starts and stops. If settings do not explain it, have the system diagnosed; do not bypass controls or safety devices to force it to run.

Request help for the system you actually have

Start a heating request and confirm the equipment selection, service city and state, symptoms, and urgency. Use the equipment-specific links above for a heat pump, boiler, or mini-split. The provider confirms the next step and price; submitting a request does not reserve an appointment.