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

Let’s go over 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 issues include:

  • 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 few 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 greater than the room’s current temperature. If you have a programmable thermostat, make sure it has new 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 found 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 start.
  • Is the air filter clean? A dirty 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 depends on what’s wrong.

2. Furnace Won’t Stay Lit

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

  1. Your thermostat detects the temperature has fallen and tells your furnace to turn on.
  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 lit.

If something is wrong 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 sense a flame, it will shut off your furnace to keep natural gas from spilling 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 senses backdrafting. Backdrafting is hazardous, because carbon monoxide and natural gas can leak 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 force your furnace to shut down 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 fluctuate 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 instances, this problem is tied to a wrong thermostat setting or a dusty air filter that’s limiting airflow. Follow the steps above to resolve the issue.

4. Furnace Won’t Turn Off

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

If this isn’t what’s happening, ensure 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 seem 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, forcing your furnace to 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 square footage

Stanford Heating & Cooling Can Solve Your Furnace Issues Quickly and Affordably

Furnace issues can be a costly headache, but not when you call Stanford Heating & Cooling. We’ve been providing the quality, affordable furnace repair Bloomfield homeowners have relied on since {year}. Call us at 812-825-8695 to receive your free estimate today.