If you have an electric furnace not blowing hot air, you’ve got one of the issues discussed below.
Here are the top reasons for an electric furnace blowing cold air – and what you or an HVAC technician can do to solve the issue. If you’re an experienced homeowner, this list might be enough to make you say, “Aha! That’s it!” If you’d like more details, read down for details.
This electric furnace troubleshooting checklist is fully explained below.
Did you Know? Most heat pump systems have electric heaters in the air handler. While not technically an electric furnace, the function is nearly identical. So most of these “electric furnace not blowing hot air” issues apply to standard split system heat pumps too.
Why is My Electric Furnace Blowing Cold Air – Checklist
- The Thermostat is Set to Fan or AC
- Your Thermostat is Bad – Not Calling for Heat or Giving Wrong Signal
- The Contactor is Bad – Coils Not Being Energized
- One or More Coils are Burned Out
- The Filter is Very Dirty
- Circuit Controlling the Heating Coils is Tripped
- Leaking Ducts – Especially Non-insulated Ductwork
- Needs to Warm Up – Give it a Minute
- Heat Sensor not Working
Reasons for an Electric Furnace Blowing Cold Air
Let’s troubleshoot electric furnace issues and offer solutions.
The Thermostat is Set to Fan or AC
Your thermostat has several settings including Fan and Cool (which usually means AC/air conditioning). It is quite possible that your thermostat is set to a position other than heat.
Solution: This is an easy fix. Check the thermostat, and if the setting is wrong, switch it to Heat.
The Thermostat is Bad
The furnace might be in perfect working condition. But if the thermostat is broken, it could be causing the fan to run without the coils energized to create heat.
Solution: Obviously, it’s time for a new thermostat, if this is the issue. However, it is a good idea to have a technician check the system to determine if this is the reason the electric furnace is blowing cold rather than one of the other issues on our list.
We’ve produced a Thermostat Buying Guide with options, costs and ideas for replacing your thermostat with one designed for the system you have. These include digital, programmable and smart thermostats including links to top brand reviews like nest, ecobee, Lux, Honeywell and more.
The Contactor is Bad – Coils Not Being Energized
According to electric furnace specialist Ed Beal, “The heating elements are turned on with a heavy duty relay called a contactor. Sometimes the contacts get pitted and do not connect, this may be the problem. Turning on and off can help reseat the contacts. On home units once they start failing they need to be replaced.”
If you have an electric furnace not blowing hot air and the other solutions don’t work, this could be your issue.
Solution: The contactor must be replaced, obviously. Also called an electrical relay, the part costs anywhere from $30 to $100.
Is contactor replacement a DIY job? It can be if you have good skills and experience. This video shows you how to troubleshoot contactor problems.
Replacing the contactor simply involves removing the bad one by loosening the screws holding it in place (if it has them), disconnecting the wiring, and installing the new one.
Of course, the key is to get a replacement contactor with the same volts and amps as the old one. The label on the contactor will probably give you that information.
Pro Tip: Before removing the old contactor, take a picture of the wiring, so you’ll have a visual to use when connecting the wires to the new contactor.
One or More Coils are Burned Out
Both electric furnaces and heat pump air handlers use electric resistance heating coils. Most look like one of these examples.
An electric coil can burn out with normal wear or be blown by a power surge. It’s pretty common. When a coil is out, the furnace’s blower might run – and all you’ll get is cool air.
Solution: Replacing the coil is the only fix for this issue. In fact, if one coil is out on an older electric furnace, we recommend replacing them all. When one wears out, the others will likely wear out shortly.
Electric coil replacement is also a DIY job if you have the right part and good skills. Watch a video tutorial, and follow it closely. Working with electricity can be very dangerous, so know what you’re doing. Make sure the circuit to the furnace is turned off at the electric panel – and you might want to lock the box too, so nobody turns it on by accident.
If you don’t have experience, we recommend getting free local HVAC quotes using our partner service.
The Filter or Coils are Very Dirty
How can a dirty filter lead to the electric furnace not blowing hot air?
Well, when a furnace filter is dirty, it might feel like the electric furnace is blowing cold air – even if it is making hot air. In short, when airflow is restricted, the heated air won’t get out, or you won’t feel it as warm as it should be.
Dirty heating coils can also cause them to heat ineffectively.
Solution: Check the furnace filter in the unit or air handler. Replace the filter if it’s been a while or if it is visibly dirty. If it is a cleanable, permanent filter, follow the manual’s instructions for how to clean it. As for cleaning, you can DIY. Open the cabinet – take off the door. Locate the coils, if possible. You might have to unbolt them and slide them out. Using a shop vacuum hose, carefully vacuum off the coils. If you can, reach the hose into the cabinet and remove dust and debris. See if that work. Hopefully it will.
Circuit Controlling the Heating Coils is Tripped or Off
Here’s another simple fix. Check the electric panel. Find the circuit that controls the electric furnace heating elements. It should be labeled.
Solution: If it isn’t labeled, look for a circuit that is in the Off position or an “in between,” tripped position. Turn it to the On position, and see if the furnace heats.
When a circuit is tripped, it might have to be turned off before it can be turned back on. Give it a try.
Did you Know? If the circuit continues to trip each time you flip it back on, then there is something wrong with the furnace – perhaps a short in the wiring or one of the elements.
Leaking Ducts – Especially Non-insulated Ductwork
Your furnace might be cranking out the heat, but if the hot air is leaking into your attic, basement or other area, you won’t feel it.
Sometimes duct leaks get worse over time, so you might not notice that you’re losing heat until the weather gets really cold and you think, “Wow, the furnace isn’t keeping up!”
Other times, a joint or connection in the ductwork comes apart all at once, and no more warm air comes out of the grates!
If your blower is running, but little air is coming out of one or more grates, then damaged ductwork is a prime candidate for what is wrong with the electric furnace system.
Solution: Inspect exposed ducts in the basement, attic, basement – wherever they exist. Have any of them become disconnected? Are there gaps in them?
If you DIY, get high-quality duct tape or mastic tape, hold the duct together, and tape it up. The job might need a second set of hands.
A furnace technician can also fix, seal and insulate ductwork. In rare cases, ducts might need to be replaced. It’s worth having ducts inspected yearly when you have your electric furnace or HVAC system cleaned and serviced.
Did you Know? All exposed ductwork should be insulated. According to Energy Star and the DOE, as much as 30%. Here are tips from the Department of Energy on Minimizing Energy Losses in Ducts.
We strongly recommend sealing and insulating any exposed ductwork, whether or not this turns out to be the reason for the electric furnace not blowing hot air. There’s a lot more information about ductwork, types, design and costs in our HVAC Ductwork Replacement Cost & Buying Guide.
Needs to Warm Up – Give it a Minute
Electric coils heat up very quickly. However, once the furnace blower starts, it has to push unheated air out of the ducts before the heated air can flow through the grates.
If your home is large, and you’re at a point quite distant from the furnace, it might take a moment or two for the heated air to reach the grate near you.
Solution: Wait a minute to see if the air warms up. If it doesn’t, then it is fair to say you might have one of the other electric furnace problems on this list.
Heat Sensor not Working
Your electric furnace has a heat sensor to make sure the furnace is producing heat. When the thermostat is satisfied, i.e., once the furnace has heated your home to the point called for on the thermostat, the sensor turns off the blower fan.
If the sensor is failed, it might not signal the blower fan to turn off. This, of course, would cause the electric furnace to continue to run without creating heat – and would be the electric furnace blowing cold air.
Solution: Check the temperature setting on your thermostat and the temperature of the air. Most digital thermostats show both. For example, if the thermostat setpoint is 74 degrees and the thermostat reads 74 or higher, but the blower is still running, this could well be the issue.
You could try replacing the sensor yourself, but it’s best that the system and the sensor be inspected and repaired by an HVAC technician.
Still Have Electric Furnace Issues?
This guide to an electric furnace blowing cold air covers 95% of the issues technicians find when inspecting units that aren’t working correctly. If your furnace isn’t blowing hot air after troubleshooting it and trying solutions, contact our service for free electric furnace repair estimates from prescreened, licensed and insured electric furnace technicians in your area.