Your furnace is a key part of your home. Without one, you wouldn’t be able to stay warm during the winter. Yet furnaces can have some problems that are more common than others.

Let’s go over these issues and discuss what they might cost to correct so you know before you call an HVAC technician. Some of the most common furnace repair issues involve:

  • Furnace won’t turn on
  • Furnace doesn’t stay lit
  • Furnace won’t blow hot air
  • Furnace won’t turn off

1. Furnace Won’t Turn On

There are a couple of reasons why your furnace won’t turn on, so make sure to go through all of them.

  • Is your thermostat set right? Make sure it’s on “heat,” “auto” and that your preferred temperature is higher than the room’s current temperature. If you have a programmable thermostat, make sure it has fresh batteries.
  • Is the circuit breaker tripped? Your furnace can’t run if it doesn’t have electricity. Reset the switch if it’s facing the outside of the electrical panel.
  • Is the furnace switch off? Your furnace has a power switch located on or close to it. Because this switch looks like a light switch, it’s easy to unintentionally turn it off. If it was off, it might take your furnace a few minutes to turn on.
  • Is the air filter clean? A dirty air filter can create a lot of issues for your furnace. Get a new one if you can’t see light through it.

Estimated Repair Cost

This issue can be complicated, so the estimated cost to repair it depends on what’s wrong.

2. Furnace Won’t Stay Lit

Your furnace uses a specific sequence when it starts heating your home.

  1. Your thermostat notices the temperature has dropped and tells your furnace to start running.
  2. The draft inducer fan turns on to bring in fresh air for combustion.
  3. The gas valve opens for the burners, which are lit electronically.
  4. The flame sensor tells your furnace the burners have been lit.

If something is off during the sequence, your furnace will shut down as a safety precaution.

A couple of possible causes for this issue include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t sense a flame, it will shut off your furnace to keep natural gas from spilling into your home. The ignition process corrodes flame sensors as time passes. While cleaning during annual furnace maintenance can help, yours may eventually need to be replaced.
  • Bad limit switch. This safety feature will shut off your furnace if it senses backdrafting. Backdrafting is hazardous, since carbon monoxide and natural gas can seep into your home. These switches can fail due to age, damage or dust buildup.
  • Old thermostat. If your thermostat isn’t working correctly, your furnace won’t be able to run.
  • Dirty air filter. A dirty air filter can limit airflow and cause your furnace to shut down to avoid overheating. Make sure to replace yours every 30 to 90 days, or anytime you can’t see light through it.

Estimated Repair Cost

These costs are estimates, so it’s important to note yours may vary based on your furnace’s brand and model.

  • Flame sensor: $350–$500
  • Limit switch: $150–$300
  • Thermostat: $150–$350
  • Furnace filter: $10-$30

3. Furnace Won’t Blow Hot Air

In many cases, this problem is tied to an incorrect thermostat setting or a dirty air filter that’s restricting airflow. Follow the steps above to fix the problem.

4. Furnace Won’t Turn Off

If it’s extremely cold outside or you like your home to be toasty, your furnace may be working for a long time.

If this isn’t the case, ensure your thermostat is set correctly and working properly. If your fan setting is at “on,” the blower motor will be running even when the furnace isn’t, so it’ll sound like your furnace is on all the time.

Alternatively, there might be a problem with the blower motor or your ductwork may be leaking air, making your furnace run continuously to make up for the air loss.

Estimated Repair Cost

These costs are estimates, so it’s important to note yours may vary based on your furnace’s brand and model.

  • New blower motor: $250–$800
  • Seal ductwork: varies based on house size

1st Choice Heating & Air Conditioning Can Resolve Your Furnace Problems Quickly and Affordably

Furnace issues can be a costly headache, but not when you call 1st Choice Heating & Air Conditioning. We’ve been delivering the quality, affordable furnace repair Lake Forest homeowners have relied on since {year}. Call us at 949-204-0859 to request your free estimate today.