Electric furnaces are usually pretty dependable, but like anything else, they can sometimes malfunction. If your electric furnace is blowing cold air or won’t heat up, it could either be a mechanical or electrical issue.
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There are a few main reasons your electric furnace is blowing cold air: the filter is dirty, the ductwork is leaking, or the heat strips are not working. Additionally, it could be caused by your thermostat not working properly or even simply being on the wrong setting.
Throughout this post, I’ll show you why your electric furnace isn’t blowing hot air and what you can do about it. I’ll also provide you with a few preventative maintenance tips.
1. Electrical Issues
There are a number of electrical issues that could be the culprit, but we’ll check the easiest one first.
Tripped Circuit Breaker
It’s possible that you simply have a tripped circuit breaker. Most electric furnaces have two circuits that power the unit. One circuit usually powers heat strips and the other powers the fan, control board, and perhaps more heat strips.
If the breaker for the primary heat strip(s) is tripped, you will not get your full heat, if any at all. The result will be cool or lukewarm air coming out of your vents.
Go to your breaker panel and take a look at your breakers. Hopefully, it is clearly labeled and you can spot your furnace breaker(s) right away.
If one is tripped or off, reset it by turning it all the way to the off position and then back on. Even if it looks like it is on, cycle it off and on once to be sure.
Note: In most cases, there are also circuit breakers on the furnace itself. You will want to check and cycle those as well.
If you’re not 100% sure of your ability to fix electrical appliances, I strongly suggest contacting a professional to help you diagnose and repair these issues. Not only will you be assured of a clean repair job, but you’ll also ensure your safety and that of your household members.
Read: Why Furnace Keeps Running And No Heat?
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2. Air Duct Leaks and Clogs
Damaged air ducts are one of the most common causes of central heating not working. When there’s a hole in the duct, some of the heat escapes through it. This worsens if the leak or tear is closer to the electric furnace. Debris and mold buildup can likewise cause air duct leaks and clogs.
How To Fix?
Pressuring the air ducts will remove excess debris, but you might have to patch them with aluminum tape if there are leaks. Most technicians will clean air ducts in sections because they often come apart. Vacuuming the ducts is an excellent way to eliminate mold spores, preventing them from spreading and clogging the vents.
Read: Cracked Heat Exchanger In Furnace – How To Troubleshoot?
3. Clogged or Broken Filters
Every furnace has a built-in filter. Some of them are reusable, while others are single-use filters. If the filter is clogged with debris or there’s a tear in the mesh, it needs to be replaced or repaired. (Note: Furnace filters have different locations depending on the furnace. Check the user’s manual to find yours.)
How To Fix?
Inspect, clean, or repair the air filter. A clogged or damaged filter is one of the main reasons your electric furnace can’t blow hot air. Pull the filter out of the vent, then wash it in the sink or with a hose. Never reuse single-use filters because they can break apart.
Read: Why Furnace Is Leaking Water?
4. Malfunctioning Sensor
Some furnaces have sensors in the air ducts to provide accurate readings to the thermostat. If these sensors are malfunctioning, they might tell the thermostat that the air is already hot enough, and the furnace will not produce hot air.
How To Fix?
Test each sensor with a multimeter or a voltmeter to ensure it’s getting enough power. After turning on the circuit breaker, you can place the hot and neutral probes on the sensors to know if they’re getting either 120v or 220v, depending on the breaker they’re connected to.
If all signs indicate that they have power but aren’t working for some reason, replace the affected sensors.
I like the Fluke 302+ Digital Multimeter with Amp Clamp (available on Amazon.com). It’s a great all-around meter that will be adequate for most needs. The quality of Fluke is well attested to and is the top choice among professionals.
If you need something a bit less expensive, you might try the AstroAI or the Kaiweets meter. Though, I can’t personally speak to their reliability, as I have not used them.
Read: Does Closing AC Vents Save Electricity?
5. Vent Problems
If your air vents are closed, broken, clogged, or otherwise hindered, they won’t be able to produce hot air. A lot of heat will absorb into the metal blades and go back into the HVAC ducts. This process can cause leaks and overheated furnaces in the long run.
How To Fix?
First, make sure the furnace is turned off so you can work on the vents safely. Next, locate the vents in your home and unscrew the grills to open them. Since the vents are small, narrow spaces, the best way to clean them is with a powerful vacuum. You can drop by your local hardware store and ask them about vacuums that work best for cleaning vents.
6. Drain Line Is Dirty
If the drain line is filled with condensation, it will also cause your electric furnace to blow cold air. The drain line should be located at the bottom of your furnace.
How To Fix?
Remove and wash the drain line to let condensation drain properly. Locate the pipe and the drain pan at the bottom of the unit, then wash both pieces with a garden hose. You can also scrub them with soap if necessary. Make sure you dry them thoroughly before you use the furnace again.
Read: How To Reset Lennox Furnace?
Preventive Maintenance for Electric Furnaces
There are many ways to prevent your electric furnace from blowing cold air after repairing it.
- Clean the vents regularly. Clean the filter every three to six months or as instructed by the manufacturer. Use a stiff brush to clean each of the vents around your home. This will prevent mold and other debris from clogging the airways. It’ll also ensure that the filter doesn’t get clogged too quickly.
- Make sure the filter is pointed in the correct direction. The arrows should face outward. Otherwise, it won’t filter out the dust and debris properly.
- Scrub and maintain the cabinet or garage around the electric furnace. Renaud Electric recommends cleaning the storage cabinet because it prevents all of the debris from clogging the filter.
- Inspect your air ducts annually or hire a technician. Leaks should be patched with aluminum tape, mold should be removed immediately, and broken connections should be replaced. Some technicians offer multi-month warranties that could pay dividends if something goes wrong.
- Turn off your thermostat when you’re not home. If your thermostat runs around the clock, it’ll cause a lot more wear and tear. This process eventually leads to damaged sensors, control boards, and capacitors. You can use smart apps with many modern thermostats if you want a warm home before you arrive.
- Maintain your home’s ambient humidity. Keep the humidity between 35% to 45% with dehumidifiers and humidifiers. This will prevent mold growth, mildew, rot, rust, corrosion, and other problems that could harm your electric furnace.
Final Thoughts
If your electric furnace isn’t heating your home, it’s time to take action. Dirty filters and leaky air ducts have other consequences besides preventing your house from feeling warm. For example, they can cause expensive damage to the drywall, wood rot, mold growth, and more. Following the aforementioned suggestions will keep your HVAC system in good shape.