Troubleshooting and Repair of Common Furnace Problems

Furnace Repair and Maintenance Guide

Furnace problems can sometimes prove difficult to diagnose. For homeowners unsure about repairs, small problems might be easy to fix, while complex problems may require repairs or an entirely new furnace. As such, troubleshooting furnace problems and knowing when to self-repair the unit and when to contact an HVAC professional is important. This knowledge can save both time and money. 

This guide includes troubleshooting tips, common repair and maintenance problems and advice on when to call a professional for furnace repairs.  

Find a Certified Heating & Cooling Professional In Your Area

Contact a top-rated local expert to help with all of your home’s HVAC needs.

Common furnace problems

While furnaces are resilient, at some point, a homeowner might have a problem or concern that needs addressing. Heating system technicians should fix advanced problems with thermostat settings, pilot lights and gas. However, homeowners can fix common problems like clogged air filters.

The most common furnace problems are related to:

A dirty furnace or clogged air filter

Furnaces need regular cleanings for peak efficiency. If ducts become dirty or clogged, it’s hard for heated air to circulate into the home evenly. If an air filter builds up with dirt and debris, it can decrease the airflow or cause the furnace to turn off. An HVAC contractor can clean the ducts, or the homeowner can contact a duct cleaning service. Estimated costs are $90 to $250.

A broken thermostat

Thermostats set heating and cooling for the home. If a thermostat breaks, an HVAC contractor should make any necessary repairs. For units beyond repair, a replacement unit might be necessary.

Estimated costs are $20 to $40 for a new, non-programmable thermostat. Programmable thermostats cost between $20 and $120, while thermostats with Wi-Fi can run from $100 to $250. 

A faulty control board

Control boards, like computer circuit boards, are complex components. If a control board breaks, this an HVAC repair technician must replace it. Estimated costs are $600 to $1,000. 

Electrical problems 

Typical electrical problems with furnaces include tripped circuit breakers and blown fuses. These are inexpensive problems that an HVAC technician can fix. However, for more serious problems, an electrician might be required. 

Motor problems

Blower motors push air into the ductwork to heat the home. When the motor isn’t functioning properly, the furnace can’t adequately heat the home. Homeowners can fix some capacitor problems, but others require an HVAC technician. Estimated costs for blower motor repairs hover around $150, while new motors can run from $450 to $600.

Pilot light ignitor problems

While older gas furnaces use gas-powered ignition with a pilot light, a new furnace might include an electric igniter. If the ignition system is faulty or fails to light, it’s unsafe for homeowners to try and restart the ignition. Restarting requires a professional contractor’s assistance. If they can’t restart the ignition, they may need to replace the ignitor.

Factors that can affect repair costs

Repair costs can vary depending on if furnace and parts are still under warranty. The types of repairs required, costs for replacement parts, and the fee the HVAC professional charges can also affect final pricing. Some furnaces include lifetime warranties on their heat exchangers, while fuel-efficient furnaces usually include longer warranties for parts. 


High-efficiency furnaces might have 10-year warranties, and lower efficiency furnaces often include five-year warranties. A manufacturer might include a one-year warranty for labor. Checking the warranty beforehand can save homeowners on out-of-pocket repair costs.

Labor costs

Labor costs can also vary. Homeowners may need to pay a surcharge for emergency work performed after hours. When hiring a repair professional to diagnose furnace problems, typical inspection fees cost $69. An HVAC professional might charge $60 to $70 per hour for repairs, not including the cost of replacement parts.

Repair costs can also vary depending on a furnace’s make and model. If parts are more expensive than the furnace, it might be cheaper to replace the entire furnace. A professional HVAC contractor can make recommendations and estimate repair costs.  

General maintenance tips for furnaces

Furnace installation costs range from $2,000 to $6,000. High-efficiency furnaces cost more upfront, but homeowners will save more on energy bills over time. On average, furnaces last from 15 to 18 years. If units over 15 years old continuously break down, it might be cheaper to buy a new furnace. 

Regularly scheduled maintenance

To keep a furnace running continuously, it’s important to have regular maintenance performed. Regular maintenance is the best defense to help avoid costly repairs and improve the system’s performance over time. Annual preventative maintenance can increase the unit’s efficiency and reduce the likelihood that the furnace will break down. Preventative maintenance costs vary from one HVAC company to the next. Estimated costs are about $100 for routine maintenance. 

Checking warranty coverage  

To save on furnace repairs, homeowners should check their warranty, as certain parts might be covered. Some furnaces include lifetime warranties. Others provide coverage for 10 years, five years, or one year. 

Homeowners can also ask their HVAC contractor for a free quote. An HVAC contractor can make recommendations about specific parts. They can also make suggestions for a replacement furnace if replacement parts are more expensive than the existing unit.

Maximizing the life of a furnace

homeowners should take the following steps to maximize the life of their furnace. 

  • Change the filter every two or three months with regular use (or more frequently with heavy use and/or if there are pets or allergy sufferers in the home)
  • Check any recommended gauges or connections
  • Turn the furnace on once each season even if it’s not in use
  • Schedule yearly maintenance with an HVAC professional

See also: Manufacturer’s Defect or Installer Error: Who’s to Blame When Your Furnace Dies Young?

HVAC Brands

Learn more about your home's heating and cooling system with our guides, how-to's, FAQ's, tips and more.

Ready to get a quote from an HVAC contractor?

Let us know what type of service you need and we can connect you with a certified local HVAC contractor.

Please enter a valid name

Please enter a valid phone number

Please enter a valid zip code

There are no dealers in this zip code.

Please enter a valid email address

Please select repair or replace

Please select heating, cooling or both