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

Let’s review these problems and discuss what they might cost to fix 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. The Furnace Can’t Start

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 correctly? 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 power. 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 near 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 dusty air filter can cause a lot of problems 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 varies according to what’s wrong.

2. My Furnace Isn’t Staying Lit

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

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

If something is wrong during the sequence, your furnace will shut down as a preventive measure.

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 prevent natural gas from getting into your home. The ignition process corrodes flame sensors as time passes. While cleaning during annual furnace maintenance can help, yours may ultimately need to be replaced.
  • Bad limit switch. This safety feature will shut off your furnace if it detects backdrafting. Backdrafting is dangerous, because carbon monoxide and natural gas can seep into your home. These switches can malfunction due to age, damage or dust buildup.
  • Old thermostat. If your thermostat isn’t working correctly, your furnace won’t be able to operate.
  • Dirty air filter. A dirty air filter can restrict airflow and force your furnace to shut off to avoid overheating. Make sure to change yours every 30 to 90 days, or whenever 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. My Furnace Is Blowing Cold Air

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

4. My Furnace Can’t Stop Running

If it’s very 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, make sure your thermostat is set correctly and running properly. If your fan setting is at “on,” the blower motor will be going 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 constantly 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 square footage

Gilray Heating and Cooling Can Get to the Bottom of Your Furnace Problems Quickly and Affordably

Furnace problems can be an expensive headache, but not when you work with Gilray Heating and Cooling. We’ve been providing the quality, affordable furnace repair Wausau homeowners have relied on since {year}. Contact us at 715-301-0727 to request your free estimate today.