Video: Why is My Electric Furnace Blowing Cold Air? 11 Reasons＆Ways to Fix
Figure 1: Furnace in a basement.
An electric furnace is a reliable and efficient way to keep your home warm during the colder months. However,
encountering the issue of your electric furnace blowing cold air can be both frustrating and uncomfortable.
In this comprehensive guide, we'll explore common reasons for this problem and provide practical solutions to get
your electric furnace back in working order.
1. 11 Reasons for an Electric Furnace Blowing Cold Air and How to Fix
1.1 It Needs Time to Reach the Set Temperature
When the furnace begins working, it does not blow warm air out from the ducts instantly, because it needs some time
for the air to be heated.
Solution:
At this point what you have to do is to wait a few minutes to see if the hot air blows out.
If your electric furnace is taking an unusually long time to reach the desired temperature, you should do the
following:
1. Check the thermostat settings: Ensure that the thermostat is set to the desired temperature. If it's programmed
for energy-saving setbacks, it might delay reaching the set temperature.
2. Inspect insulation: Poor insulation in your home can contribute to heat loss. Consider improving insulation in
doors and windows to help the furnace maintain the set temperature more efficiently.
Figure 2: Components of an electric furnace from www.ahrinet.org.
1.2 Wrong Thermostat Setting and Calibration Issue
The thermostat serves as the command center for your electric furnace, dictating when to heat and when to cool.
Incorrect settings or a miscalibrated thermostat can result in the furnace blower fan blowing cold air.
Solution:
1. Check thermostat settings: Ensure that your thermostat is set to the desired temperature for heating. Verify that
the mode is set to "heat" and not "cool" or "fan only." If your thermostat has programmable settings, review and
adjust them as needed.
2. Calibrate the thermostat: If you suspect a calibration issue, consult your thermostat's manual for instructions
on recalibrating. If you're unsure or uncomfortable doing this yourself, consider seeking professional assistance.
1.3 Faulty Thermostat
A malfunctioning thermostat can lead to inaccurate temperature readings and improper furnace operation.
Solution:
Calibrate or replace the thermostat: If you suspect a thermostat issue, recalibrate it according to the
manufacturer's instructions. If problems persist, consider replacing the thermostat.
Figure 3: Digital thermostat.
1.4 Electric Furnace Heating Coil Failure
Heating elements are the heart of an electric furnace, responsible for warming the air before it is circulated
through your home. If one or more heating elements fail, the furnace may blow cold air.
Solution:
Visual inspection and replacement: Carefully inspect the heating elements for signs of damage or breakage. If you
notice any issues, it's advisable to replace the faulty elements. This task may require professional expertise, so
consult with a technician if needed.
1.5 Very Dirty Heating Coil
Accumulated dirt and debris on the heating coil can impede its efficiency, leading to cold air blowing through the
vents.
Solution:
Regular maintenance: Schedule regular maintenance checks, including cleaning the heating coil. This can be done by a
professional HVAC technician to ensure optimal performance.
1.6 Air Filter Clogged
A clogged air filter restricts airflow, diminishing the furnace's ability to heat the air effectively and even
causing the furnace to overheat. If overheated, the furnace might shut off its heating elements but continue blowing
air.
Solution:
Replace the air filter: Check and replace the air filter regularly, ideally every 1-3 months, depending on usage. A
clean filter promotes proper airflow and helps prevent various furnace issues.
Figure 4: Dirty air filter in a Furnace.
1.7 Tripped Circuit Breaker
Each heating coil in an electric furnace has its own dedicated circuit breaker. Overloads or short circuits can cause
these breakers to trip.
Solution:
Inspect and reset circuit breakers: Check the circuit breakers associated with the heating coils. If one has
tripped, reset it. If the problem persists, consult a professional electrician.
1.8 Defective Heating Coil Relay/Contactor
The relay or contactor controls the flow of electricity to the heating
coil. If it's defective, the coil won't receive power.
Solution:
Professional assessment: A faulty relay or contactor requires professional attention. An HVAC technician can
diagnose the issue and replace the defective component.
1.9 Blown Fuse
A thermal fuse acts as a safety mechanism, shutting off the
furnace if it detects overheating. A blown fuse in the furnace's electrical system can disrupt the heating process,
resulting in cold air blowing from the vents.
Solution:
Replace the blown fuse: If you identify a blown fuse, replace it with one of the same amperage. If the issue recurs,
consult a professional for a more in-depth inspection.
Figure 5: Checks voltage on geothermal HVAC system.
1.10 Heat Sensor Not Working
The heat sensor is crucial for regulating the furnace's
temperature. A malfunctioning sensor can
lead to cold air issues.
Solution:
Professional inspection: If you suspect a faulty heat sensor, it's advisable to have a professional HVAC technician
assess and replace the component as needed.
1.11 Air Duct Leak
Leaky air ducts can allow warm air to escape before reaching the intended rooms.
Solution:
Inspect and seal ducts: Check for visible leaks in the air ducts and seal them with appropriate materials.
Professional duct cleaning and sealing services can also address this issue effectively.
Figure 6:Furnace system.
2. Conclusion
In conclusion, troubleshooting and fixing an electric furnace blowing cold air requires a systematic approach. While some issues can be resolved with basic maintenance, others may necessitate professional intervention. Regular upkeep and prompt attention to problems will ensure your electric furnace operates efficiently, keeping your home warm and comfortable. If you encounter persistent issues, don't hesitate to seek assistance from qualified HVAC professionals.
