TL;DR
No heat is an emergency if you smell gas, a carbon monoxide alarm goes off, you see smoke or smell hot wiring, or someone at home is a baby, elderly or medically fragile and the house keeps getting colder. Otherwise, in Orange County it can usually wait until morning. Check the thermostat, breaker, filter and furnace door first. Last winter our median diagnostic visit billed $95.
It is late, the house is getting colder, and the furnace is either silent or running and blowing air that never warms up. You are trying to decide whether this is a call-someone-now problem or a pile-on-the-blankets problem.
Here is the same triage our team walks callers through. A handful of situations are real emergencies and should not wait a minute. Most no-heat nights in Orange County are not one of them, and a few causes are things you can fix yourself in five minutes.
No heat right now and not sure it can wait? Call (949) 590-3296 or book online.
When is no heat an actual emergency?
Treat it as urgent tonight if any one of these is true:
- You smell gas. Natural gas has a rotten-egg or sulfur smell added to it. Do not troubleshoot the furnace. Get out first, then call (steps below).
- A carbon monoxide alarm is sounding, or people in the house have headaches, dizziness, nausea or confusion that ease when they step outside. Get everyone out and call 911. Carbon monoxide has no smell, so the alarm is your warning.
- You see smoke or scorch marks, or smell hot wiring or melting plastic at the furnace. Turn it off at the thermostat and the furnace switch, and leave it off.
- Someone at home is especially vulnerable to cold: a baby, an older parent, or anyone with heart or breathing problems, and the house keeps dropping with no safe backup heat.
What is not on the list: the outside temperature by itself. Overnight lows in most of Orange County rarely get close to freezing, so burst pipes are not a realistic risk for most homes here. A cold night is miserable, but not dangerous for a healthy household with blankets.
If you smell gas
Follow the gas company’s steps, not a furnace checklist. Leave the house right away. Do not turn lights, appliances or the thermostat on or off, and do not light anything. Once you are outside and away from the house, call SoCalGas or 911. Do not try to find or stop the leak yourself. Once the gas company clears the house, we can find out what failed on the furnace.
The gas-leak steps follow SoCalGas’s own guidance, which also warns not to rely on smell alone. The carbon monoxide symptoms and the groups most at risk (infants, older adults, and people with heart disease or breathing problems) come from the CDC. Sources: SoCalGas – Natural Gas Leak; CDC – Carbon Monoxide Poisoning Basics.
What should you check first when the heat won’t come on?
If none of the emergency signs apply, run through these five safe, no-tool checks before calling anyone.
- Thermostat. Set it to Heat (not Cool, Auto or Off), a few degrees above room temperature. If the screen is blank, replace the batteries. One of last February’s calls in our records was a six-year-old ecobee that went dark the day after a rainstorm and would not power up. A dead thermostat and a dead furnace look the same from the couch.
- Breaker and furnace switch. Check the panel for a tripped breaker labeled furnace, FAU or air handler, then look near the furnace for a switch that looks like an ordinary light switch. If a breaker trips again right after you reset it, leave it off and call.
- Filter. A badly clogged filter can make the furnace overheat and shut itself off on a safety limit. If yours is gray and matted, swap it. More in can a dirty furnace filter cause no heat.
- Furnace door. The panel over the blower presses a safety switch. If it was not seated after a filter change, the furnace will not run at all.
- Status light. Most modern furnaces have a small blinking light visible through the lower panel. Count the blinks, match them to the chart on the door, and write the code down.
If all five check out and there is still no heat, the problem is inside the furnace: ignition, the flame sensor, a pressure switch, the inducer or blower motor, or the control board. That is where the DIY part ends.
Can no heat wait until morning in Orange County?
Usually, yes. If nobody in the house is at special risk and there is no gas smell, CO alarm or burning smell, a night without the furnace here is uncomfortable rather than dangerous. To get through it safely:
- Pull everyone into one or two rooms and close the doors to the rest of the house.
- Use an electric space heater only if it has tip-over and overheat shut-off. Plug it straight into a wall outlet, not an extension cord, and keep it well clear of beds and curtains.
- Never heat the house with a gas oven, stovetop, grill, camp stove or generator. All of them produce carbon monoxide.
- Leave the furnace off if it was banging, cycling on and off, or smelling hot. Resetting it over and over can turn a small failure into a bigger one.
In the morning, call early and tell us what the thermostat showed, whether the furnace tried to start, and any error code.
What our job records show about no-heat calls
Furnaces in Orange County work a short season, and our records show it. From October 2025 through March 2026 we logged 986 jobs, and only 22 were written up with “no heat” in the notes. Most heating-season work was planned: 285 preventative maintenance visits and 224 service diagnostics. Irvine was our busiest city, with 108 of those jobs, followed by Mission Viejo with 44.
A few of those no-heat situations, with identifying details removed:
- An older homeowner in south Orange County. Last winter a family member called us about no heat at a relative’s house running on a system from the early 2000s. That is the scenario from the emergency list: the person in the cold house is the one at risk.
- Heat set to 73, house stuck at 67. One homeowner watched the furnace blow cool air for about 40 minutes without the temperature moving, then shut the heat off out of worry about carbon monoxide. When you are unsure, turning it off is never the wrong move.
- A furnace as old as the house. In a home built in 1985, the original furnace would start its exhaust fan, but the pilot would not light. At close to 40 years old, that call was booked as a replacement consultation rather than a repair.
- Three weeks of resets. Another system would start, the blower would not come on, and it shut itself off with an error code no matter how many times it was reset. Resets do not fix a failed part; they just delay the call.
On cost: last winter our Service Diagnostic visits billed a median of about $95, and the middle half of priced visits ran $95 to $325, including any repair finished on the same visit. When a part had to be ordered, the return Service Follow Up visits ran $422 to $850 (middle half of 19 priced jobs), median around $767.
DIY or call a pro?
Safe to do yourself: thermostat settings and batteries, resetting a tripped breaker once, the furnace switch, the filter, seating the door panel, reading the status light, and making sure vents are open and not blocked by furniture.
Where DIY stops: the gas valve or gas line, the burner compartment, electrical parts beyond a single breaker reset, a breaker that trips again, a furnace that lights and then shuts off over and over, and any gas, burning or electrical smell. Never bypass a safety switch to get the heat back; those switches exist to shut the furnace down when something is unsafe. On a heat pump, anything past the thermostat, breaker and filter involves refrigerant and high voltage, so it is pro-only.
No heat and not sure what is wrong?
We find the cause, tell you honestly whether it could have waited, and give you the price before any work starts.
When the furnace is out, our furnace repair techs cover Irvine, Laguna Hills, Mission Viejo and all of Orange County. If the air never warms up, see our guide to a furnace blowing cold air, or our carbon monoxide safety checklist.
Frequently asked questions
Is no heat considered an HVAC emergency?
It is when there is a safety risk: a gas smell, a carbon monoxide alarm, smoke or an electrical burning smell, or a vulnerable person in a house that keeps getting colder. For most healthy households in Orange County, a furnace that will not start is urgent but can wait for a morning appointment.
Why is my furnace running but blowing cold air?
The burners are not lighting or not staying lit. Common causes are a thermostat fan set to On instead of Auto, a clogged filter tripping the high limit, a dirty flame sensor, or a failed igniter. Check the first two yourself; the others need a tech.
How much does it cost to have someone look at a furnace with no heat?
Our Service Diagnostic visits last heating season billed a median of about $95, with the middle half between $95 and $325, including repairs done on the spot. If a part has to be ordered, the return visit is priced separately, and you get that price before the work.
Should you keep resetting a furnace that shuts off?
One reset after a power blip is fine. If it shuts down again, stop. Repeated resets can overheat parts that are already failing, many furnaces lock themselves out after several failed tries, and the error code is more useful to the tech than another restart.