Furnace Blowing Cold Air? Causes, Fixes and Same-Day Repair
Why the blower runs but the air never warms up — and how we fix it in one visit
A furnace blowing cold air is most often a dirty flame sensor that shuts the gas off seconds after ignition while the blower keeps running. Other common causes are a thermostat set to FAN ON instead of AUTO, a clogged filter tripping the high-limit switch, a failed hot-surface igniter, a pilot light that has gone out on older units, or a condensate drain blockage on 90%+ furnaces. Check the thermostat and filter first. If that does not fix it, DC Air and Heating repairs most cold-air faults same day across the Antelope Valley and Santa Clarita Valley — flame sensor service runs $140–$240 and igniter replacement $220–$420. Call (661) 310-3340.
Key Facts
- Same-day dispatch for calls before 4 PM, seven days a week
- $89 diagnostic waived when you approve the repair
- Flame sensors, igniters and pressure switches stocked on every truck
- Carbon monoxide test included on every heating call
- Heat pumps checked for defrost mode and auxiliary heat failure
- One-year labor warranty on every repair
| What you notice | Likely cause | Typical repair |
|---|---|---|
| Warm for a few seconds, then cold | Dirty flame sensor | $140 – $240 |
| Fan runs constantly, never warm | Thermostat set to FAN ON | Free — switch to AUTO |
| Clicks, no flame, cold air | Cracked hot-surface igniter | $220 – $420 |
| Warm, then cold, then warm | Clogged filter / high-limit trip | Filter change, then inspect |
| Water near a high-efficiency unit | Blocked condensate drain | Quoted on inspection |
| Heat pump blows cool in the morning | Defrost cycle or auxiliary heat | See heat pump repair |
Estimated range only — get an exact written price with a free in-home consultation or use our Instant Quote tool. Get an Instant Quote or call (661) 310-3340.
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Areas we serve
Dispatched from our Quartz Hill shop to the Antelope Valley, Santa Clarita Valley, north San Fernando Valley and Kern high desert.
- Lancaster
- Palmdale
- Quartz Hill
- Santa Clarita
- Valencia
- Canyon Country
- Newhall
- Saugus
- Stevenson Ranch
- Castaic
- Acton
- Agua Dulce
- Littlerock
- Pearblossom
- Lake Los Angeles
- Sun Village
- Leona Valley
- Lake Hughes
- Green Valley
- Antelope Acres
- Rosamond
- Willow Springs
- Mojave
- California City
- Edwards AFB
- Tehachapi
- Sylmar
- San Fernando
- Granada Hills
- Porter Ranch
- Northridge
- Chatsworth
- Van Nuys
- Phelan
- Pinon Hills
- Wrightwood
Frequently Asked Questions
Why is my furnace blowing cold air?
The most common cause in Antelope Valley homes is an oxidized flame sensor. The burners light, the sensor cannot confirm the flame, and the control board shuts the gas valve while the blower keeps moving unheated air. Desert dust speeds that buildup, which is why it is our number-one winter call.
Can I fix a furnace blowing cold air myself?
Check three things safely: the thermostat is on HEAT and AUTO (not FAN ON), the filter is not clogged, and the furnace breaker and service switch are on. Anything past that — flame sensors, igniters, gas valves — involves gas and high voltage and should be handled by a licensed technician.
Is a furnace blowing cold air dangerous?
Usually not, but it can be. If you smell gas, hear a loud bang at ignition, or a carbon monoxide alarm sounds, leave the house and call from outside. Every heating call we run includes a CO test at no extra charge.
How fast can you fix a furnace blowing cold air in Palmdale or Lancaster?
Usually the same day. Calls placed before 4 PM are typically handled that afternoon or evening, and dispatch texts you the technician's name and arrival window. Call (661) 310-3340.
My heat pump blows cold air in the morning — is it broken?
Not necessarily. Heat pumps briefly blow cooler air during a defrost cycle on frosty mornings. If it lasts more than 10–15 minutes, or the outdoor unit is encased in ice, the defrost board, sensor or auxiliary heat strips likely need service.
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