No Heat at Night: Safe Steps Before You Call a Technician

By Proair Air Conditioning Services, CSLB C-20 License #776028. Published October 30, 2026. Updated October 30, 2026.

No heat? What to do before you touch the furnace

Start at the thermostat and work toward the furnace. These checks are safe for anyone and they solve more no-heat nights than you would think.

1. 1

   Read the thermostat

   Set it to Heat, raise it a few degrees above room temperature and look for a blank screen. A blank screen usually means dead batteries.

2. 2

   Check the breaker and the furnace switch

   Most gas furnaces still need electricity. Look for a tripped breaker and a wall switch near the unit that looks like a light switch.

3. 3

   Pull the filter

   A clogged filter can overheat a furnace until a safety switch shuts the burners off. Replace it if you have a spare.

4. 4

   Seat the door panel

   A loose lower panel holds a safety switch open and the furnace will not start. Press it firmly into place.

5. 5

   Give it a few minutes

   After any change, wait for the start-up sequence. If it tries, fails and locks out, stop there.

Why do gas and carbon monoxide come before the thermostat?

A cold night is when a house is shut tight and everyone is asleep. CDC says carbon monoxide symptoms are often flu-like: headache, dizziness, weakness, nausea, vomiting, chest pain and confusion. It also warns that people who are asleep can die before they show any symptoms. So if the whole family feels unwell, do not blame a bug and go back to bed.

A working alarm is the only warning a sleeping house gets. CPSC says to put CO alarms on every level and outside sleeping areas, with battery power or battery backup, and to test them monthly.

What about a pilot light that went out?

Older furnaces and most gravity wall heaters use a standing pilot, a small flame that burns all the time. If yours is out and there is no gas smell, the owner’s manual gives the relight steps for that model. If you are not comfortable doing it, wait.

SoCalGas lists a no-cost pilot relight service, with a furnace safety check on the same visit, at socalgas.com or 1-877-238-0092. Check the current terms when you book. If the pilot lights and goes out again, leave it off, because the part that keeps it lit may have failed.

Newer furnaces have no pilot. They use an electronic igniter, so there is nothing for you to relight. Our furnace repair page covers those faults.

Other systems have their own quirks. A gravity wall heater needs no electricity, so go straight to the pilot. A heat pump blowing cool air in heat mode may be in a defrost cycle, so give it several minutes and check that the thermostat says Heat. Our heat pump repair page covers what comes next if it stays cold.

If the stove and water heater went out along with the furnace, the gas may be off to the whole house. Do not turn the meter back on yourself. Call SoCalGas, because the utility restores service after the piping and appliances are checked.

How do you stay warm safely until morning?

Heating a house the wrong way causes more harm than a cold night does. Close off unused rooms, gather everyone in one room, use extra blankets and layers, and keep the doors shut to hold the heat you have.

CPSC also advises against leaving a space heater running while you sleep. Turn it off before bed and rely on layers once the room is warm.

California requires CO alarms in homes with fuel-burning appliances. If yours are missing or the batteries are old, fix that before the next cold night, because carbon monoxide has no smell.

When a cold house becomes a health problem

South Gate winters are mild, but CDC names older adults without enough heat and babies sleeping in cold bedrooms among those most at risk of hypothermia. In adults, watch for shivering, exhaustion, confusion, fumbling hands, slurred speech and drowsiness. In infants, watch for bright red, cold skin and very low energy. A body temperature below 95°F needs medical attention right away, so call 911.

Do not wait for those signs if someone at home is frail. Stay with a relative or neighbor who has heat. Ready LA County points people without a working heater to senior centers, community centers, malls and libraries during the day, and 211 LA County can give referrals at any hour.

When should you stop and leave it off?

Any one of these means the furnace stays off until a technician has seen it.

• The breaker trips a second time.
• The furnace fires, shuts off and repeats.
• You hear banging at start-up or see soot near the unit.
• A burning electrical smell comes from the cabinet.
• A control light flashes a pattern. Count the flashes and tell the technician.

Calling for a no-heat repair

Our posted hours are Monday to Saturday, 9 to 5, closed Sunday, so a Saturday evening failure means a Monday call. Our emergency furnace repair page explains how we handle urgent no-heat calls in those hours.

We serve Lynwood, South Gate and the surrounding cities. Have the furnace model, the symptom and any flash pattern ready. A fall furnace tune-up catches dirty flame sensors and weak igniters before the first cold night finds them.

A few notes from tonight make the morning call more useful. Write these down while you remember them.

• The type of heater: gas furnace, wall heater or heat pump
• Which checks you ran, and whether anything changed
• What you heard at start-up: a click, a whoosh, the blower or nothing
• How long it ran before it shut down
• Who is at home, especially infants or older adults

What matters most tonight

Keep the order straight. Gas smell, CO alarm or anyone feeling sick means everyone goes outside and you call 911. With those ruled out, run the five checks and stop at the first sign of a real fault. A furnace left off overnight usually costs less to fix than one forced to keep restarting. Call us in the morning with your notes. We will find the fault, explain it plainly and give you the price before any work starts.