Common Reasons For Furnaces Blowing Cold Air: Your Thermostat is Set Incorrectly. The Furnace Filter is Dirty. Your Furnace Has Overheated. The Condensate Line is Clogged.
First and most importantly, make sure your thermostat is set to Heating Mode. Next, verify that the thermostat's fan is set to AUTO, not ON. If it is set to ON, that may be your problem; switch it immediately. The ON setting makes the furnace fan blow continuously, even when the heating cycle is not activated.
The most common reason a heat pump is blowing cold air through your air vents is defrost mode. This is a safety feature to melt frost and ice within the system. During defrost mode your heat pump made switch modes to heat up the outdoor coils. Indoor temperatures will fall because the system is briefly in cooling mode.
If the heat is running and your house has oddly cold rooms, they are unevenly heated, or vents or radiators aren't giving off much heat – there could be a problem with heat delivery. Insulating your home will surely help keep the heat inside, but it first needs to be properly delivered.
Typically, there's a 10 to 15 minutes allowance for this. However, if after this time it's still producing cold air, then there's an underlying problem that needs to be addressed. It would be wise to turn the furnace off and get in touch with a pro immediately for help dealing with the issue.
Simply reset the thermostat to AUTO. What causes the heater fan to emit cold air is the ON switch allows the fan to operate even when heat isn't required to maintain temperature control. Checking the pilot light and seeing if it is out could be a quick fix also. If the pilot is out you can try relighting it.
Most modern thermostats will have a clearly marked reset button inside the panel. It's usually small and recessed, so you might need a pointed object like a paperclip to press it. For those wondering specifically how to reset air conditioner thermostat models, the process is generally the same.
A furnace blowing cold air could be the result of a leak in your ducting. Over time, the changing temperatures wear on all sorts of things, including your ductwork. In fact, it's rather normal for ductwork to develop leaks over time. When ductwork has a leak, cold air will enter a duct and blow into your home.
One of the most common culprits when a heater isn't working efficiently is dirty air filters. These can restrict the flow of heated air into your home. Remember, regular checks and replacements are essential for smooth HVAC system operation.
Make sure all vents and radiators are open and not blocked by furniture or curtains. Blocked vents can prevent the warm air from circulating freely in your rooms. It's also a good idea to bleed your radiators to remove any trapped air that can cause cold spots and reduce their efficiency.
The Wrong Thermostat Settings
The first thing you should check if your heat pump is blowing cold air in the winter is your thermostat settings. You need to ensure that your thermostat is set to “Heat” and the fan is set to “AUTO.” If your fan setting is set to “On,” your heat pump will blow air, whether heated or not.
Dirty filters, leaky ducts, and poor insulation can cause cold return vents. Leaky ducts often cause cold air to blow even after cranking the heat up. 20-30% of air, especially hot air, is lost because of leaky ducts. Cracked, holey ductwork needs sealing or replacement.
Check your thermostat's batteries and replace any that are exhausted or defective. Clean all of the parts of your furnace, especially the ones that are susceptible to dust and dirt. You could also hire HVAC technicians to clean the system thoroughly. Ensure that the gas valve is open and not obstructed by any debris.
Check the thermostat
Maybe your heater is not blowing hot air even though the fan is running. As a result, any air that blows out of the vents while your heater is off will usually feel cold. In such a case, there could be an easy solution, particularly if your thermostat setting is the problem.
While furnaces can stop operating for complicated reasons, home owners should check a few usual suspects first behind a lack of hot blowing air: Electrical problems causing a loss of power. Blocked air vents and ducts restricting airflow. Improperly configured thermostat settings.
If your heat pump is on but not blowing hot air, it could be due to a dirty air filter, low refrigerant levels, or a malfunctioning thermostat. The outdoor unit may also be iced over, or the reversing valve may not be working properly. Contact a professional for further inspection.
If your furnace is blowing cold air in your home, this is a sign of an issue with the flame detector, gas supply, air filter, pilot light, or condensate lines. Many of these issues are able to be easily solved on your own by sanitizing or replacing components in the gas furnace.
Some of the most common thermostat issues include:
The thermostat is broken, not properly level, or dusty. The thermostat needs to be recalibrated. There is loose wiring causing a thermostat issue.
Yes, you should turn your heater off if it's blowing cold air to prevent potential damage to the system. Running a malfunctioning heater can strain the components, leading to more significant issues and increased energy usage.
It May Be Blowing Relatively Cooler Air
Given that the ideal thermostat setting is at 68 degrees, blown air at 90 degrees is actually warmer than what is needed for heating. However, it is cooler compared to the average body temperature of 98.6 degrees, which makes it feel cool, and is often mistaken for cold air.
Press the reset button. Most models require you to hold the button down for 3-5 seconds before releasing. Restore power to your AC. Restore power to the unit at the circuit breaker, and make sure the unit is set to “on” and your thermostat is set to “cool.”