No heat in the house at all

When the whole house is cold, start with safety, then the simple things: power, the thermostat setting, and the furnace switch and breaker. If your heat is trying to run but not warming the house, we'll point you to the guide that fits what you see.

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Before you start. If you smell gas or rotten eggs, a carbon monoxide alarm is sounding, anyone feels dizzy or sick, or you see smoke or flames, get everyone out now. Don't touch switches or use a phone inside, and call 911 or your gas utility once you are outside.

Every question and answer on this page, in order

Question 1: Do you notice any of these right now?

Check this first. Your safety comes before the heat.

A gas or rotten-egg smell, or I'm not sure it isn't gas: Emergency: leave now and call from outside
A carbon monoxide alarm is sounding, or anyone feels dizzy, sick or has a headache: Emergency: leave now and call from outside
Smoke or flames: Emergency: leave now and call from outside
A burning plastic or hot electrical smell, with no smoke: Stop: a burning or electrical smell
None of these: go to question 2

Question 2: Are the lights and outlets working in the rest of the house?

Yes, everything else has power: go to question 3
No, the power is out in all or part of the house: Likely cause: the power is out

Question 3: What kind of heat do you have?

Warm air from vents in the floor, walls or ceiling usually means a furnace or a heat pump. Radiators or baseboards with pipes usually mean a boiler.

A furnace that blows warm air through vents: go to question 4
A heat pump with an outdoor unit: Next step: the guide that fits what you see
Radiators or baseboards: Next step: the guide that fits what you see
I'm not sure: go to question 4

Question 4: Set the thermostat to Heat, a few degrees above the room temperature, and wait a few minutes. What happens?

It was off, on Cool, or set too low, and the heat came on once I fixed it: Likely cause: a thermostat setting
The thermostat screen is blank: Next step: the guide that fits what you see
The furnace clicks or tries to start, or the fan blows cold air: Next step: the guide that fits what you see
Nothing happens at all, no sound from the furnace: go to question 5

Question 5: Check the furnace switch and the furnace breaker. What do you find?

The furnace switch often looks like a light switch on or near the furnace. At the electrical panel, open only the hinged door, never the metal cover behind it. If the floor near the panel is wet, a breaker feels hot or looks scorched, or you smell burning at the panel, don't touch anything and pick that answer below. CDC says never to turn power on or off while standing in water. Family Handyman says to stand to the side of the panel and turn your face away when you flip a breaker. Carrier says that if the furnace breaker has tripped to the middle, push it to Off, then back to On. Do this only once.

A breaker feels hot or looks scorched, I smell burning at the panel, or the floor near the panel is wet: Stop: call a licensed electrician about the panel
The switch was off, or a breaker was tripped and it held after one reset: Likely cause: the furnace switch or breaker
The breaker tripped again after one reset: Call an HVAC technician
The switch is on and no breaker is tripped: Call an HVAC technician
I can't find the furnace switch or the breaker: Call an HVAC technician

Possible results

Need the words for the phone call? Build a what-to-tell-the-technician checklist, or read when to call an hvac pro.