Is your furnace struggling to keep your home warm and cozy? If so, it may be time to purchase a new one. While replacing your furnace may be expensive and inconvenient, waiting too long can lead to uncomfortable living conditions and sky-high energy bills.
If you’re unsure whether to replace your furnace or not, you’re in the right place. This guide will walk you through the five key warning signs that show that it’s time for a replacement, helping you make an informed decision before your existing furnace quits on you.
If you already know you want to replace your furnace, use the form below to get a quote from some of the best HVAC companies in your area.
This site receives compensation from the companies featured in this listing, which may impact where and how products appear. This listing doesn’t feature all companies, products, or offers that may be available.
Key Takeaways
- An older furnace or one that's not working as well as it used to might need to be replaced.
- Furnaces typically last between 15 and 25 years.
- Furnace repairs can be expensive, but it's often more cost-effective to replace it.
When To Replace Your Furnace
If your furnace is about to malfunction, the warning signs are often all around. Use the five points below to see whether you need to replace your furnace or not.
1. Your Furnace Is Getting Old
Even if your furnace seems to be chugging along just fine, its age can be a telltale sign that replacement is on the horizon. Most furnaces last 15 to 25 years, depending on the type and how well you’ve maintained them.
Average Lifespan by Furnace Type
As furnaces age, they become less efficient and more prone to breakdowns. However, different types of furnaces have different lifespans. Here’s a quick breakdown:
- Electric furnaces: These typically last 15-20 years. They tend to wear out faster in older houses with less efficient wiring systems, which can cause additional strain.
- Gas furnaces: You can expect these to function well for 15-20 years. However, regular maintenance is important to catch minor issues before they escalate.
- Oil furnaces: These often have the longest lifespan, lasting 15-25 years on average. However, regular filter changes and cleaning help maintain their longevity. It’s worth noting that oil furnace costs may be higher than other types of furnaces because of fuel. Oil tends to cost more than gas.
If your furnace is approaching or has surpassed these age ranges, it’s wise to start planning for a replacement. While an older furnace might still function, it’s likely operating at a much lower efficiency than newer models, costing you more in energy bills each month. You should especially consider replacing it if you have a 30-year-old furnace.
Signs of an Aging Furnace
Even if your furnace hasn’t hit its expected lifespan, there are some signs that it’s aging prematurely:
- Longer run times: If it takes longer than before to reach preferred temperatures, your furnace could be losing efficiency.
- Frequent cycling: Systems that cycle on and off more often show signs of internal wear, which can lead to permanent damage if unresolved.
- Unusual noises: Any new noises, such as clanking or whooshing, are indicators that parts might be wearing out or becoming loose.
- Visible rust or cracks in the body: These visual signs are serious indicators that your furnace could be leaking combustion by-products, posing safety risks to your household.
Remember, these signs don’t necessarily mean immediate failure, but they do suggest that your furnace is working harder than it should. Keep a close eye on these symptoms so that you can anticipate when you’ll need a replacement.
2. Your Furnace Needs Frequent Repairs
When your furnace starts to feel like a money pit, it’s time to consider a replacement. As components wear out, you might find yourself calling for repairs more often than you’d like.
Common Furnace Repairs
Some repairs are more common as furnaces age, but others are more serious. Here’s a list of some of the most common furnace repairs:
- Blower motor issues: A faulty blower motor can lead to poor airflow and uneven heating, making your furnace work harder to maintain the desired temperature. Furnace blower motor replacement costs may be steep, but they’re not as bad as paying for a full furnace replacement.
- Cracked heat exchanger: This is a serious problem that can lead to dangerous carbon monoxide leaks, posing significant health risks. If this happens, you’ll probably have to pay to replace the entire furnace.
- Ignition system problems: Difficulty starting or maintaining a flame can indicate ignition issues, and these failures can often lead to the system shutting down entirely.
- Thermostat malfunctions: An aging thermostat can cause your furnace to behave erratically, impacting both comfort and energy use.
If you’re facing multiple repairs in a short period, especially if the cost of repairs is approaching half the price of a new furnace, replacement is often the more cost-effective choice in the long run.
Compare Costs: The 50% Rule
A good rule of thumb is the 50% rule: If the cost of repairs is 50% or more of the cost of a new furnace, it’s usually more economical to replace the entire unit. This is especially true if your furnace is already past its prime in terms of age.
If you need to replace the blower motor, the thermostat, and the ignition system, you should seriously think about biting the bullet and replacing the furnace.
3. Your Energy Bills Are Steadily Increasing
A noticeable increase in your energy bills can be a clear sign that your furnace is losing efficiency. As furnaces age, they have to work harder to produce the same amount of heat, leading to higher energy consumption. If you’ve noticed a steady climb in your heating costs over the past few seasons, your furnace might be to blame.
Factors Affecting Furnace Efficiency
Before jumping to conclusions about your furnace, consider these factors that can impact efficiency:
- Leaky ductwork: Hot or cold air escaping from faulty ductwork can increase your energy bills unnecessarily. Also, if your furnace is leaking water, it can be a sign of an airflow or condensate system issue.
- Poor insulation: Insufficient insulation in attics and walls can result in thermal losses, making your furnace work harder to compensate.
- Clogged air filters: Dirty air filters are common culprits for reduced airflow and system inefficiency. Luckily, learning how to change your air filter is an easy DIY fix.
- Inadequate maintenance: Without regular HVAC preventative maintenance, your furnace’s performance is likely to decline.
Addressing these issues individually might improve your furnace’s performance. However, if you’ve ruled out these factors, it may be impossible to improve your furnace’s efficiency without a pricey repair or replacement.
4. Your Home Is Heating Unevenly
If some rooms in your home feel like a sauna while others remain chilly, your furnace might be struggling to distribute heat evenly.
Exploring Causes of Uneven Heating
Uneven heating doesn’t always have a straightforward cause, but there are a few main culprits. Ductwork issues, like leaks and blockages, can mean that hot air isn’t reaching areas far from the furnace. Similarly, areas with poor insulation will lose heat faster than the furnace can replace it, causing those rooms to remain cold.
You may also run into issues if your furnace isn’t the right size for your home. A furnace that is too small can’t adequately handle the demands of heating your entire home. If you have uneven heating, you may also have a failing blower motor. A blower that’s on its way out won’t be able to distribute air throughout your house efficiently.
While some of these issues are easy to fix, persistent problems with uneven heating often mean that it’s time for an upgrade.
5. Your Furnace Is Making Unusual Noises
A well-functioning furnace should operate relatively quietly. If your furnace has suddenly become noisy, that’s cause for concern. However, different noises can indicate various problems, so it’s important to analyze the noise before you run to the store to buy a new furnace.
Decoding Furnace Noises
If you hear banging or popping, it usually means there’s something wrong with your burners or your heat exchanger. We recommend getting a professional assessment to prevent further damage.
If you hear rattling, it usually indicates loose components or issues with the ductwork rattling because of thermal expansion and contraction. Squealing noises mean there’s probably something wrong with your blower motor or fan belt, which could cause your whole furnace to shut down.
Some noises are easy to fix, but persistent or worsening sounds often mean that your furnace is nearing the end of its life.
When To Call a Professional
If you notice any of these unusual noises, it’s best to call in a professional HVAC technician for an inspection. They can determine whether the issue is easy to repair or if replacement is the more cost-effective option.
Choosing the Right Replacement Furnace
Once it’s clear that you need a replacement, it’s time to think about choosing a new furnace. Alternatively, you could purchase a heat pump, but heat pump costs are typically higher initially, which may affect your choice.
There are different types of furnaces, so you’ll need to choose between gas, electric, or oil, based on cost-effectiveness. You should also make sure that your furnace is the right size for your home. For more information on common types of furnaces, refer to the table below:
| Type | Life span | Average Cost | Unique Benefit |
| Electric Furnace | 15–20 years | $1700 to $7000 | Energy-efficient and more environmentally friendly |
| Gas Furnace | 15–20 years | $3,800 to $10,000 | Lower fuel costs and more effective heating |
| Oil Furnace | 15–25 years | $2,500 to $10,000 | Higher BTU output, longer lifespan |
Be sure to get multiple quotes from reputable HVAC companies before making a decision. They can help you choose a furnace that’s the right size and meets your efficiency goals.
If you’re having a hard time choosing what type of furnace to buy, check out the video below to see how the process works.
Planning to replace your furnace? Check out our top furnace brands to choose from.
Conclusion
You may be dreading replacing your furnace because of the expense, but if you wait too long, your existing furnace may cost you even more in repairs and energy expenses. By paying attention to the warning signs, you can feel confident about when to replace your furnace and when to hold off until after the next repair.
If you have an HVAC issue and you need professional help, use the form below to get an estimate from a local HVAC technician.
This site receives compensation from the companies featured in this listing, which may impact where and how products appear. This listing doesn’t feature all companies, products, or offers that may be available.
