How Long Does a Furnace Last?

man opening up furnace

Like all appliances, furnaces often start encountering problems as they age. Some issues are repairable, and others indicate that a replacement is necessary. Purchasing a new furnace can come with significant costs. The following guide will help you determine whether repairing your furnace or buying a new one is more cost and comfort-efficient.

If you’re interested in buying a new furnace, read our Furnace Buyer’s Guide to learn about the options, costs, and other considerations.

How Long Do Furnaces Last?

A furnace that receives annual or bi-annual maintenance can last fifteen to twenty years. Our furnace technicians estimate that frequent inspection and maintenance can extend the lifespan of a furnace by five to ten years compared to units without regular maintenance. It may last even longer if you live in a warmer climate and don’t use your furnace as frequently. 

How Much Does It Cost to Replace a Furnace? 

The average cost for a new natural gas or propane high-efficiency furnace is $5,000 to $7,000. At Enercare, this price includes professional installation, manufacturer’s warranty, and work done to gas and electrical code by fully licensed installers.

Enercare also offers furnace rentals, which range in price from $82 to $102 per month.

The cost of a new furnace ranges higher or lower depending on the following factors:

  • Technical requirement: the size of your home, existing ductwork, type of heat source (natural gas, propane, electric or oil)
  • Code requirements: safety, licensing, building code requirements, and oil, natural gas/propane or electric code requirements
  • Environmental choices: energy efficiency, comfort-enhancing options, and any air-quality filtration add-ons
  • Personal preferences: extended warranties and maintenance plans

The table below breaks down Ontario’s average costs for new furnaces.

Furnace TypeAverage Furnace Cost (Including Installation. Does not include fuel or tanks)
Natural Gas$5,000 to $7,000+
Propane$5,000 to $7,000+
Electric$1,000 to $3,000+

6 Signs You Should Replace Your Furnace

Ideally, an HVAC expert can repair your problems and extend the equipment’s life. However, severe indicators like age, constant repairs, loud noises, or lack of heat output may require replacing your furnace. If you are experiencing any of the following issues with your heating system, consider purchasing a replacement.

1. Your Furnace is 15+ Years Old

As previously stated, many factors contribute to how long your furnace lasts. Our furnace experts expect well-maintained furnaces to last around fifteen years. Regular furnace maintenance is similar to changing the oil in your car to keep the motor running well. Not performing frequent inspections of the machine can reduce its operating efficiency and lifespan by five to 10 years. 

According to our experts, many older furnaces must be replaced because their manufacturers no longer produce the parts needed to repair the system. If your furnace is obsolete, added performance and cost efficiencies with new furnaces can make upgrading your appliance worth the upfront price. 

Additionally, over time, the heat exchanger in the furnace may deteriorate or crack. Our expert compares a heat exchanger to a car motor–a critical component that can be too expensive to repair.

2. Loud Noises During Standard Operation

Homeowners should understand what their furnace sounds like when running normally to identify abnormal noises. There may be a serious issue if your furnace is popping, rattling, screeching, humming, booming, or clicking. Our furnace expert provides potential causes for the following furnace sounds that, if heard, should prompt homeowners to contact a technician: 

  • Popping: During cold weather, a furnace typically cycles four to five times an hour. If a homeowner hears a “pop” during the shutdown, it indicates an airflow restriction inside the appliance. It may also imply delayed ignition, in which a homeowner should call a professional immediately. 
  • Rattling: Rattling may indicate something trapped in the furnace filter or blower. A loose blower wheel or belt can also cause rattling if you have an older furnace.
  • Screeching: A faulty blower or inducer motor could cause a screeching noise while your furnace operates.
  • Humming: Similarly, a seized blower or inducer motor may result in a humming noise.
  • Clicking: Clicking may result from faulty blowers or the gas valve not lighting every time the furnace attempts to start. Our expert compares this to the clicking sound that a gas stove makes when trying to ignite. Clicking is another indicator of delayed ignition, in which a homeowner should immediately turn off the furnace and call a professional.  
  • Booming: A boom during initial system startup may also indicate delayed ignition with the burners, possibly due to debris buildup. A “boom” could result in a potential safety hazard. If heard, a homeowner should contact a professional immediately. 

3. Temperature Fluctuations Throughout the Home

If you notice extreme temperature shifts throughout different parts of your home, it may indicate that your furnace can no longer distribute heat around the house. There is possibly a repairable cause to this issue (like installing proper ductwork), or it could result from your furnace’s age and need for replacement. If you’re experiencing this problem, a hired technician should be able to identify a solution or advise on appliance replacement.

4. Furnace Flames Are Yellow Instead of Blue

The burners in your furnace should always produce a blue flame. A yellow flame may indicate that your furnace produces excess carbon monoxide. It may also result from a gas leak. Most modern furnaces manufactured within the past fifteen years conceal the burners within the system, so the flames are not externally visible. In this case, a homeowner will need a technician to inspect the equipment for burner-related issues. 

5. Energy Bills Are High

The furnace’s efficiency will decrease once it reaches a certain age. If you notice your monthly energy bills are significantly increasing and you aren’t changing how much you use your furnace, it is likely due to appliance deterioration. 

Furnaces produced fifteen to twenty years ago were designed around 80% efficiency (or mid-efficiency). Today, furnaces are designed with 95-98% efficiency and will keep more heat inside your home. 

With that in mind, homeowners with furnaces between fifteen and twenty years old could realize significant savings on their electricity bills by replacing their furnaces.

6. Furnace Repairs Become More Frequent and Expensive

There comes a time in a furnace’s life when the cost of repairs is no longer worth it. If your furnace breaks down regularly and requires frequent maintenance, replacing the equipment may be more cost-effective. 

Furnace Maintenance vs. Replacement

A new furnace is a significant investment. Luckily, many furnace problems are fixable with standard maintenance. Refer to our furnace maintenance guide for a thorough list of common furnace problems. 

Not Enough Heat

Decreased heat generation can result from common furnace problems, including a dirty air filter, deteriorating air ducts, vent obstruction, or a thermostat malfunction. Review our How to Troubleshoot Your Furnace guide to identify a potential cause for the lack of heat in your home.

Dust Build-Up

Dust will naturally accumulate throughout your HVAC system. If you’ve recently renovated or remodeled your home, there may be significant dust build-up in your home. Yearly cleaning and maintenance will prevent significant problems from occurring due to dust build-up. 

The filter in your HVAC system collects common contaminants like dust mites, allergens, mold, pet dander, and more. The furnace filter should be replaced at minimum twice annually–at the beginning and end of the cold weather season. However, our expert recommends replacing the filter every two to three months for optimal efficiency and air filtration. 

Additionally, homeowners should clean the area around their furnaces before the cold weather season. This process can be as simple as vacuuming the surrounding area and wiping it down with soap and water. Additionally, keeping chemicals like cat litter away from your furnace and water heater prevents these substances from entering your furnace’s airflow. 

Rapid Cycling

Our expert says your furnace system is short-cycling if it turns off every few minutes.

If your furnace is short-cycling, our expert advises that it is typically a result of the furnace not having enough airflow due to a clogged intake or exhaust vent, a clogged filter, a clogged condensate drain, or if your ductwork was modified and too small. 

When it tries to turn on, it gets very hot and can’t output the heat, so a safety trigger inside the furnace turns the system off. A homeowner might only notice that their furnace is short-cycling on very cold days when it is needed most and isn’t generating enough heat.

Where to Turn for Help

Once you’ve determined the severity of your furnace problem, you should contact an HVAC professional and define the next steps. Whether you can get by with a professional furnace repair or need a replacement, Enercare is ready to help.