Why your furnace fails in the first cold week
Every year the first genuinely cold night in El Paso brings a wave of no-heat calls. It is not a coincidence, and it is largely preventable.
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(915) 751-9803Why do furnaces fail on the first cold night?
A furnace in El Paso sits unused for roughly eight months of the year. Dust settles on the burners and the flame sensor, small parts seize, and nothing reveals any of it until the thermostat finally calls for heat. The failure did not happen on the cold night. It happened quietly over the summer, and the cold night is simply the first time anyone asked the furnace to work.
This is the difference between a furnace and an air conditioner here. The air conditioner runs for months and tells you when something is wrong, because you are using it every day. The furnace gets switched off in March and is not asked for anything until November.
So the first cold snap is not a stress test in the way people imagine. It is simply the first time in eight months that anyone found out whether the furnace still works.
What actually goes wrong
A dirty flame sensor
A thin metal rod that confirms a flame is present. A film of dust or oxidation stops it sensing, so the furnace lights, runs a few seconds, then shuts itself down. It is one of the most common no-heat calls and one of the simplest to put right.
Dust burning off the heat exchanger
That hot, slightly acrid smell on the first run of the season is usually settled dust burning away. It should clear within an hour or so. If it does not, or if it smells like something else, switch the system off and call.
A cracked heat exchanger
The serious one. A crack can let combustion gases into the air your house breathes, which is why an inspection looks at the exchanger specifically. If we find a crack we will tell you plainly what it means.
Thermostat batteries and settings
Worth ruling out before anything else. A thermostat with flat batteries or left on COOL will not call for heat, and neither is a furnace problem.
A seized inducer or blower motor
Motors that have not turned since spring sometimes do not want to start. This often announces itself as a humming noise with no air movement.
The check that prevents most of it
A heating check before the season is not complicated. It is a technician cleaning the flame sensor, checking the burners and the heat exchanger, testing the safety controls, confirming the thermostat actually calls for heat, and running the system through a full cycle while it is still warm enough that a fault is an inconvenience rather than an emergency.
The value is in the timing. Finding a failed part in October means we order it and fit it on a normal working day. Finding the same part in January means finding it at night, in the cold, when every heating company in the city is busy.
When to book it
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October, before you need it
The point is to test the furnace while the house is still comfortable, so a fault is not urgent.
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Run it yourself first
Switch the thermostat to heat on a mild day and let it run for twenty minutes. If it does not light, cycles off quickly, or smells wrong after the first hour, you have found something worth reporting.
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Change the filter
The same filter serves heating and cooling. After an El Paso summer it has had a hard few months.
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Tell us what you noticed
Sounds, smells and how long it ran before stopping tell us more than almost anything else. It is worth mentioning even if it seems minor.
If you smell gas, do not switch anything on or off. Leave the house and call your gas utility from outside. That is a safety call, not a service call.
Questions about heating in El Paso
How often should a furnace be serviced?
Once a year, before the heating season. That holds even in a mild climate, because the months of disuse are exactly what causes the problems described above.
Why is my heater blowing cold air?
Most often the furnace is lighting and then shutting down on a safety, commonly a dirty flame sensor, so the blower keeps running without a flame behind it. It can also be a thermostat set to ON rather than AUTO, which runs the fan continuously between heating cycles.
My furnace smells like burning the first time I run it. Is that normal?
Usually yes. Dust that settled over the summer burns off the heat exchanger and should clear within an hour. A smell that persists, or one that is sharp or chemical rather than dusty, is worth a call.
Do I even need a furnace in El Paso?
El Paso winters are mild but not warm. Overnight lows drop below freezing most winters, so homes here need real heat, just not for many months of the year. That short season is precisely why furnaces here are more likely to sit with an undetected fault.
Is a heat pump worth considering instead?
For some homes, yes. A heat pump handles both heating and cooling and suits a mild winter well. Whether it fits depends on your ductwork, your electrical service and how the house is built, which is what an estimate visit is for. See our systems page.
Book the heating check
Call (915) 751-9803 or request a visit. If you would rather have it happen automatically each year, our maintenance plan covers both the heating and cooling checks. You can read what furnace work involves on our furnace repair and heating page.