If your heater is blowing cold air, check the thermostat first: it should be set to Heat, above room temperature, with the fan on Auto, not On. A heat pump can also blow cool air for a few minutes during a normal defrost cycle. If cold air keeps coming, a clogged filter, tripped breaker, failed ignitor or flame sensor, or a heat pump problem is the likely cause.
Quick checks you can do safely
- Set the thermostat to Heat and a few degrees above the room temperature
- Set the fan to Auto, not On. On runs the blower even when the heat is off, so air feels cool between cycles
- Replace dead thermostat batteries if the screen is blank or dim
- Replace or check a dirty air filter
- Check the breakers for the furnace or air handler and the outdoor heat pump. Reset a tripped breaker once; if it trips again, leave it off and call
- Make sure the furnace or air handler power switch (it looks like a light switch) is on and the access panel is closed
- With a heat pump, wait 10 minutes. If the outdoor unit is defrosting, warm air should come back on its own
Common causes of a heater blowing cold air
- Thermostat fan set to OnThe blower keeps running between heating cycles, so you feel room-temperature or cool air. Switch the fan to Auto.
- Heat pump defrost cycleOn cold desert mornings the outdoor coil frosts up. The heat pump briefly reverses to melt it, you may see steam outside, and the air indoors can feel cool for a few minutes. This is normal.
- Heat pump air feels lukewarmA heat pump delivers steady, moderate warmth rather than the very hot blast of a gas furnace. Air that feels warm, not hot, can be normal. Air that feels cold for more than a few minutes is not.
- Clogged air filterPoor airflow makes a furnace overheat. A safety switch shuts the burners off while the blower keeps running, so cold air comes out of the vents.
- Failed ignitor, pilot or dirty flame sensorOn a gas furnace, the burners will not light or stay lit. The furnace may click, try again and then lock out.
- Tripped breaker or failed heat stripsMany Surprise and Sun City West homes have a heat pump with electric heat strips for backup. If a breaker trips or a strip fails, the blower runs but the air stays cool.
- Heat pump reversing valve or refrigerant problemA stuck reversing valve or low refrigerant from a leak can leave a heat pump blowing cool air in heat mode.
- Clogged condensate drainHigh-efficiency furnaces and air handlers have drain safety switches that shut the heat off when water backs up.
- Leaky ductworkDucts in the attic that are torn or disconnected can pull in cold attic air or dump warm air before it reaches your rooms.
When to call for heater repair
Call us if the air is still cold 10 to 15 minutes after the checks above, if a breaker trips again, if the furnace clicks and shuts off, or if the outdoor heat pump stays covered in ice for hours. If you smell gas, leave the home and call your gas company or 911 first. If you smell burning plastic or electrical odors, turn the system off. See our guide to a burning smell from your heater.
We repair heat pumps, gas furnaces, electric furnaces and air handler heat strips of all brands, and there is never an extra charge for nights, after-hours or weekends. More about our heating repair service.
Heating in Surprise and Sun City West
Most homes in Surprise and Sun City West heat with a heat pump and electric backup heat, and some have gas furnaces. Because the heat sits unused for most of the year, problems often show up on the first cold nights of November and December, when desert temperatures regularly drop into the 30s and 40s. A fall heating tune-up catches most of them before you need the heat.
Related prices
| Service | Typical Price Range |
|---|---|
| Service Call | $95 |
| Diagnostic Fee | $95 (waived with any repair) |
| Thermostat Replacement (Standard) | $150–$350 |
| Pressure Switch Replacement | $200–$600 |
| Control Board Replacement | $400–$1,200 |
| Refrigerant Leak Repair | $400–$1,500 |
| Reversing Valve (Heat Pump) | $1,200–$2,500 |
Typical ranges for guidance only; your exact price is given in writing before any work begins. See our full price guide.