Over 40% of households in the United States use electric furnaces for indoor heating. But as reliable as modern heating systems may be, they aren’t programmed to choose a convenient time to develop mechanical glitches. Sometimes you’ll wake up in the middle of the night to a freezing house because, all of a sudden, your furnace decided to start blowing cold air!
Your electric furnace isn’t blowing hot air because of wrong thermostat settings, a tripped circuit breaker, a dirty air filter, a faulty sequencer, or broken heating elements. Fix the issue by checking the thermostat and circuit breaker and replacing the air filter, sequencer, and heating elements.
No matter what’s causing your equipment to blow cold air, you’ll want to fix the problem fast if you want to continue enjoying the warm air. Luckily, this article will go over the common causes behind your electric furnace not blowing hot air and how to fix them.
Wrong Thermostat Settings
When an electric furnace refuses to blow hot air, it’s often because the thermostat isn’t set right. For instance, suppose someone turned the thermostat temperature down to a level lower than the current room temperature. In that case, the thermostat won’t activate the heating cycle, and the furnace won’t blow hot air.
So, begin your troubleshooting by ensuring the thermostat is set correctly. Try turning the temperature about 10°F (5–6°C) higher than the current reading and wait to see if the furnace will start to heat. Note that this will only work if the thermostat is set to HEAT.
If your furnace continues to blow cold air, check the thermostat batteries. Just because they aren’t dead doesn’t mean they aren’t interfering with the thermostat’s operations. Even almost-dead batteries can interfere with the thermostat’s functioning. Replace the batteries and see if it solves the problem.
Still getting cold air? Check to see the fan switch is set to AUTO. If it’s set to ON, the blower motor will continue running and pushing air out regardless of its temperature. Turning the switch to AUTO will tell the blower to send air out only when the heating cycle is triggered.
If you have done all of the above and your thermostat is still having trouble starting the heating cycle, it’s time to have it checked by an expert.
Tripped Circuit Breaker
Have you had electrical work done recently? Maybe the electrician turned off the furnace circuit breaker and forgot to turn it back on. This could be the reason your electric furnace won’t blow hot air.
Sometimes the circuit breaker gets switched off automatically as a safety measure when a furnace component draws more electricity than it should, or a broken part prevents the system from functioning correctly.
To fix the problem, go to your circuit breaker box and locate the furnace switch. If it’s off, switch it back on.
If there’s a more complex problem with the system, the switch may trip again right after you flip it back on. If this happens, have your heating system inspected by a professional heating contractor. An expert will also determine if there are bad fuses in the heat handler or the circuit breaker itself is just faulty.
Dirty Air Filter
A dirty air filter could cause your electric furnace not to blow hot air for several reasons. For instance, dirt and debris can make their way to the heating elements.
Clogged heating elements won’t heat properly to give you the warm air you crave so much.
And not just that. Dirt buildup on a furnace filter can restrict airflow, causing the system to overheat. When this happens, the furnace safety switch will trip the circuit breaker to prevent damage to the system. You might think the furnace is producing cold air, but it’s actually shut off.
The only way to fix this problem is by cleaning or replacing your air filter. To clean a reusable furnace filter, remove the filter, run it underwater, then set it out to air dry. If your furnace uses a disposable filter, throw it away and install a new one. Make sure to clean or replace your filter every 30–90 days.
If you suspect some of the filter’s filth has found its way to the inside of your furnace, have an HVAC technician inspect the unit. It could save you from expensive repairs in the future.
The furnace sequencer is positioned between the thermostat and heating elements. Its job is to turn the elements on and off in sequence to ensure they aren’t drawing electric current all at once, causing overheating or a circuit overload.
When room temperature dips below the thermostat’s temperature, the thermostat sends a signal to the sequencer. The sequencer passes current to one element at a time and repeats the process until all elements are heated to warm the air available in the furnace.
If the sequencer is faulty, it won’t turn on enough heating elements, which could be why your electric furnace isn’t blowing hot air. A broken sequence could also cause your furnace circuit breaker to trip.
Several things could make a furnace sequencer fail. The most common is a bimetal switch being stuck between the on or off position or being loose from wear. Not using your furnace for extended periods can also make the sequencer malfunction.
Unfortunately, bad furnace sequencers can’t be repaired; they can only be replaced. Thankfully, they don’t cost much, and the replacement process doesn’t take much time.
However, unless you have experience disconnecting furnace parts and connecting wires, you should have an HVAC pro do it.
Broken Heating Elements
A heating element can burn out or stop warming air due to old or broken wires. If this happens, your electric furnace won’t have enough functional elements to produce heat, and you’ll find that it’s blowing cold air.
You need a clamp-on ammeter to test the heating element and fix this problem. An ammeter will help you identify broken or faulty wires.
You have to replace all the broken wires to get your heating elements working again. You can probably already guess that this task requires experience in reading an ammeter and replacing wires. As such, it’s best left to professionals.
If your electric furnace isn’t blowing hot air, it’s wise to have it checked by an experienced heating contractor. Nonetheless, you can try several things to solve the problem on your own, like:
- Ensuring the thermostat is set correctly.
- Switching on tripped circuit breakers.
- Cleaning or replacing a dirty filter.
Leave advanced repairs like replacing a broken sequencer or heating element to an expert.