My Heater is Blowing Cold Air

It can be quite frustrating to turn on the heater when it is chilling cold, only for you to realize it is blowing cold air. This could happen due to various reasons. However, there are several DIY remedies to resolve this issue. 

Why Is My Heater Blowing Cold Air?

Want to know why your heater is blowing cold air? Here are the likely reasons and trusted solutions.

Your Heater Hasn’t Warm Up Enough.

If you are just turning the heater on or increasing the temperature, you might have to give the heater some time to warm up. It may take from five minutes to ten to warm up. After this, you should start feeling the warm air from your heater. However, if, after 10 minutes, your heater is still blowing cold air, then there might be something else.


If you live with people, check with them to see if they have not tweaked the temperature. Temperature preference may differ, so while you want it warm, someone else might prefer it cool.


If number 1 and 2 isn’t the issue, the next item on the list is to check the thermostat. If your thermostat is set to on instead of auto, the heater will continue to run even if it is not on the heat cycle. If this happens then, cool air will pass through the unit. A thermostat adjustment is all that is required to fix this.

Some thermostat runs on battery power, if your thermostat is such, check to see if you have a weak or dead battery and replace it. Also, if it is a smart thermostat, make sure all settings are correctly done.

Check the Heat Pump

Not all heaters have a heat pump. However, if your heater has a heat pump, it might possibly be covered in ice or snow. This may cause your heater to malfunction, therefore, resulting in your heater blowing cold air. Regardless, if this is the case, all you need to do is get the ice or snow off the pump. And your heater should work properly again.

If this doesn’t solve it, it could be that your heat pump either has bad valves or it is low on refrigerant. Whichever the case may be here, only a professional can fix and correct it.

The Breaker may be Tripped.

A tripped breaker is the cause of many issues associated with heaters. If the breaker of your heater is tripped, the heat won’t get in. And, in some cases, the heater may not work at all. Check the breaker and if it has tripped, turn it back on. 

The same goes for gas heaters, too, as they all have electric starters to light up the gas burner. If the breaker has tripped, the heater might be on. However, warm air won’t get in. You will only get the same temperature as what is outside. 

Check the Pilot Light 

The pilot light indicates that there is a continual supply of gas. Once this light goes off, it means something has interrupted that supply. If there is no gas supply to your heater, it could lead to your heater blowing cold air. Turn off the gas valve in the pilot assembly for about three minutes, then switch to pilot settings. Place a lit match to the opening and hold reset till the pilot light comes on again. If this doesn’t work, then a professional might have to come to check your heater.

Check the Flame Sensor

The flame sensor alerts the heater to come on and warm the air around. If your flame sensor is dirty or covered in dust, it might not detect when the burners are on, and even worse, it might not allow the light. This will also affect the heater and make it blow cold air.

Green Air Engineering is your trusted source for all cooling and heating repairs and installations. We serve the entire South Orange County. Give us a call for a free estimate.