Your furnace is an integral part of your home. Without one, you wouldn’t be able to keep warm during the winter. Yet furnaces can have some issues that are more typical than others.

Let’s go over these problems and discuss what they might cost to fix so you know before you contact 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. My Furnace Can’t Start

There are a few 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 desired temperature is greater than the room’s current temperature. If you use a programmable thermostat, make sure it has new batteries.
  • Is the circuit breaker tripped? Your furnace can’t operate 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 near it. Because this switch looks like a light switch, it’s easy to unintentionally turn it off. If it was off, it may 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 problem can be complicated, so the estimated cost to repair it varies according to what’s wrong.

2. My Furnace Ignition System Isn’t Working

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

  1. Your thermostat detects the temperature has dropped and tells your furnace to start running.
  2. The draft inducer fan activates 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 ignited.

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

A couple of possible causes for this problem include:

  • Dirty or malfunctioning flame sensor. If the sensor doesn’t sense a flame, it will turn off your furnace to prevent natural gas from getting into your home. The ignition process corrodes flame sensors over time. While cleaning during annual furnace maintenance can help, yours may ultimately need to be taken out and changed.
  • 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 accumulation.
  • 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 cause your furnace to shut down to avoid overheating. Make sure to replace 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 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. The Furnace Won’t Blow Hot Air

In many cases, this problem is tied to a wrong thermostat setting or a dusty air filter that’s restricting airflow. Use the steps above to fix the issue.

4. The Furnace Can’t Shut Down

If it’s extremely cold outside or you like your home to be warm, 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 going even when the furnace isn’t, so it’ll sound like your furnace is running all the time.

Otherwise, there might be an issue with the blower motor or your ductwork may be losing air, forcing your furnace to run constantly to make up for the lost air.

Estimated Repair Cost

These costs are approximations, so it’s necessary to note yours may be different based on your furnace’s brand and model.

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

James Heating & A/C, Inc Can Get to the Bottom of Your Furnace Issues Quickly and Affordably

Furnace problems can be an expensive headache, but not when you call James Heating & A/C, Inc. We’ve been providing the quality, affordable furnace repair Lexington homeowners have trusted since {year}. Call us at 336-853-6070 to receive your free estimate today.