When the heat fails at night in Menlo Park, Atherton or Portola Valley, the first job is deciding whether anyone is in danger. A gas smell, a carbon monoxide alarm, a burning smell or a breaker that keeps tripping comes before any talk of repairs. A furnace that will not light on a 40-degree night is uncomfortable, but it is a different kind of call. Here is what to do in the first minutes, what can wait until morning, and how a 24/7 visit works.
If you smell gas
- Get everyone out of the house now.
- Do not flip light switches, unplug anything, touch the thermostat or start a car in an attached garage. Any of these can make a spark.
- Do not make calls from inside. Once you are outside and away from the house, call the gas utility or 911.
- Stay out until they say it is safe. Then call us to find the cause and restart the heating safely.
Treat any gas smell that lingers as a leak until someone with a detector says otherwise.
If the carbon monoxide alarm sounds
- Get everyone, pets included, outside into fresh air.
- Call 911 from outside. Say if anyone has a headache, dizziness, nausea or confusion.
- Do not silence the alarm and go back in to “air the house out”.
- Before the furnace runs again, have the heat exchanger, venting and burners checked, even if the fire crew found no obvious source.
Carbon monoxide has no smell, so the alarm is the only warning you get. An alarm that chirps now and then, rather than sounding continuously, usually means a low battery or an alarm at the end of its life. Replace it the same day.
Other reasons to shut the system off now
- Burning or hot-plastic smell, smoke or scorch marks at the furnace or a register. Turn the furnace off at its service switch and keep it off.
- A breaker that trips again after one reset. Leave it off; resetting it again and again can damage a motor or the wiring.
- Water pouring from an attic furnace, or a ceiling stain spreading below it. A blocked condensate drain is the usual cause. Turn the furnace off and catch the water.
- Flame outside the burner area, or a loud bang or roar you have not heard before.
Call now, or first thing in the morning?
| Situation | What to do |
|---|---|
| Gas smell, CO alarm, smoke | Get out, call 911 or the gas utility from outside, then call us |
| Burning smell, repeated breaker trips, water leaking | Turn the system off and call now |
| No heat, and someone at home is an infant, elderly or medically fragile | Call now |
| No heat, everyone well, a mild night | Call to get on the schedule; ask whether a morning visit avoids the after-hours charge |
| One cold room, the rest of the house fine | Book a regular furnace repair |
Safe checks while you wait
Only when there is no smell, no alarm and no tripped breaker:
- The thermostat is on Heat, set a few degrees above room temperature, with fresh batteries if it uses them.
- The service switch by the furnace, which looks like a light switch, is on.
- The furnace’s front panel is pushed fully closed. A loose panel leaves a safety switch open and the furnace will not start.
- The filter is not packed with dust.
- On a high-efficiency furnace, the white plastic vent pipes outside are not blocked by leaves or plants.
- Count the flashes on the status light, then turn the power off and on once. If it locks out again, leave it off.
Keeping warm until the repair
Electric space heaters are the safe stopgap: models that shut off when tipped, kept about three feet from bedding, curtains and furniture, and plugged straight into a wall outlet rather than an extension cord. Never heat the house with a gas oven or range, a barbecue, a camping heater or a generator. If you have a heat pump with backup heat and the outdoor unit is frozen solid, the thermostat’s emergency-heat setting can carry the house until the visit.
How a 24/7 call works
Call (650) 567-5385, any day and any hour. Expect safety questions first, then the basics: gas furnace, heat pump or electric heat; where it sits (attic, closet, garage); what it is doing; any code on the status light.
On site, the technician first confirms there is no gas leak or carbon monoxide problem, then works through ignition, venting, airflow and the electrical side. If the part is on the truck, the heat comes back on the same visit. If it is not, or the equipment cannot run safely, it stays off and you get a written next step, with a follow-up visit to finish the repair.
When the furnace should not be restarted
A cracked heat exchanger, a damaged or disconnected vent, a scorched control board or repeated flame rollout means the furnace stays off. Putting an unsafe furnace back in service to get through the night is not a repair. This is where replacement planning starts: furnace installation and heat pump installation explain what that involves and what to compare. Estimates for replacement systems are free.
For cooling and other system failures, see our guide on what to do when the heating or cooling stops.