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

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

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

1. The Furnace Isn’t Turning On

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

  • Is your thermostat set right? Make sure it’s set to “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 found on or close to it. Since this switch resembles a light switch, it’s easy to accidentally 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 cause a lot of issues for your furnace. Replace yours if you can’t see light through it.

Estimated Repair Cost

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

2. The Furnace Won’t Stay Lit

Your furnace uses a certain sequence when it begins heating your home.

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

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

A couple of possible causes for this issue include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t detect a flame, it will shut off your furnace to prevent 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 dangerous, since carbon monoxide and natural gas can seep into your home. These switches can malfunction due to age, damage or dust accumulation.
  • Old thermostat. If your thermostat isn’t working properly, your furnace won’t be able to run.
  • Dirty air filter. A dirty air filter can reduce airflow and force your furnace to shut down to prevent 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 necessary 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. The Furnace Blows Cold Air

In many cases, this problem is tied to an incorrect thermostat setting or a dusty air filter that’s limiting airflow. Follow the steps above to resolve the issue.

4. My Furnace Can’t Shut Down

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

If this isn’t the case, make sure your thermostat is set correctly and running 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 running 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 approximations, 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

GV Heating & Air Will Work Hard to Get to the Bottom of Your Furnace Problems as Soon as Possible

Furnace problems can be an expensive headache, but not when you work with GV Heating & Air. We’ve been providing the quality, affordable furnace repair Crystal and Twin Cities homeowners have relied on since year. Call us at 763-535-2000 to receive your free estimate today.