The temperatures are dropping. The cool breezes are picking up. Yes, autumn in Tennessee is spectacular. It might just be the perfect time of year! But sooner or later, the temperatures will drop even more, the breezes will go from cool to freezing, and you’ll need to know that you can rely on your heating system. Well, can you? Or might it be on its last legs?
A furnace can last for many years, especially if it receives maintenance every single year. Sadly, though, nothing lasts forever. One day, the time will come when a furnace is ready to retire, and you’ll have to get a new one. Has that day arrived? We’ll help you figure that out.
How do you know when it’s time to replace your furnace?
You may need to replace your furnace if:
- Your system is 15 to 20 years old and nearing the end of its lifespan
- Repairs are becoming frequent or expensive
- Energy bills are steadily increasing despite normal usage
- Your home has uneven heating or comfort issues
Your furnace makes unusual noises or struggles to keep up in cold weather
Does Your Furnace Require a Repair Now?
If you’ve got a heating system you’re concerned about, one of the biggest things that might be on your mind is that there are repairs that must be done now, or you might not have reliable heat for the winter. If this is the case, get a clear estimate of what the repair will cost, and compare the price you may pay for a major repair with typical furnace installation costs, which often range from $3,800 to $12,000 depending heavily on fuel source. The higher the cost, the greater the investment, so you’ll only want to get a very expensive repair if you’re confident the furnace will last you quite a while after that. For help evaluating performance and efficiency, it’s useful to understand furnace efficiency ratings explained and what they mean. Furnace efficiency is measured by AFUE, with standard models starting around 80% and high-efficiency condensing units reaching 95% AFUE or higher.
We would consider yearly repairs to be frequent. If your furnace sometimes needs repairs multiple times in a single winter, that’s very frequent! Small repair costs add up, and once a furnace starts needing repair more and more often, it is time to replace furnace.
Does Your Furnace Require Repairs Frequently?
Even if the repair that’s needed now is small, you should take into consideration just how often these small repair needs are coming up. We would consider yearly repairs to be frequent. If your furnace sometimes needs repairs multiple times in a single winter, that’s very frequent! Small repair costs add up, and once a furnace starts needing repair more and more often, it is heading toward retirement.
Does Your Furnace Receive Annual Maintenance?
As long as you have a tune-up from a qualified technician every year, and replace filters as part of routine maintenance to protect efficiency and indoor air quality, an electric furnace can last up to twenty years, and a gas one more like fifteen. But without that maintenance, the wear and tear will cause damage that can’t be undone. A heating system that only gets serviced when it breaks down might only last half as long as it should. Be sure you’re keeping up with essential fall furnace maintenance tasks to protect your investment.
Does Your Furnace Heat Effectively?
You shouldn’t ever feel like your heating system can’t maintain even comfort throughout your whole house, leaving some areas too hot or too cold. Insufficient heat, or uneven heat with some warm rooms and others that stay chilly, can be a sign that an old furnace is not long for this world. If your HVAC equipment is the wrong size for your home, replacing both systems may solve inconsistent temperatures and high utility bills. Oversized systems can short-cycle and increase humidity, which matters during muggy Hendersonville summers. If you’ve had routine maintenance or repair and are still not happy with your furnace’s performance, you should be aware that replacement is not far off.
Does Your Furnace Heat Efficiently?
Again, the key to this is maintenance. Without it, your furnace’s efficiency will drop several percent each year, which adds up quickly; unlike a furnace and air conditioner, cooling performance for an air conditioner is judged by a seer rating, and the Seasonal Energy Efficiency Ratio 2 (SEER2) rating measures ac efficiency, though local efficiency and comfort also depend on proper sizing for Hendersonville’s Climate Zone 4A conditions. After just five years, you’ll experience about a 25% drop in efficiency! But if you’ve been good about scheduling routine maintenance, the system’s efficiency should not drop at all… until it gets old enough that no amount of service can balance out the wear and tear of a long lifetime of heating. Hendersonville’s four-season weather, with humid summers and freezing winter temperatures, means homes need a Manual J load calculation as part of the sizing process to match the system to the home size and required power. And when you’re replacing heating equipment, it’s also smart to consider the paired cooling side, since the right thermostat and stronger energy efficiency can help lower long-term operating costs and protect the system’s lifespan over time.
Weighing the Factors
A furnace that’s still young and well-maintained, rarely needs repair, and works effectively and efficiently is worth spending money to repair. A furnace getting on in years, a furnace with a spotty or nonexistent maintenance record, a furnace that needs frequent repair or needs a very expensive repair right now, or a furnace that is ineffective or inefficient are all factors that should have you planning your furnace installation in Brentwood, TN, along with the age of the full hvac system, compatibility with the air conditioner, and whether replacing one component or both makes better financial sense. The furnace and air conditioner share the same blower and duct work to move conditioned air through your home, so a poor match can hurt performance. Replacing both at once is often cheaper because labor is consolidated, and one of the key benefits is the chance to save on labor while better managing long-term energy costs; modern matched equipment may also offer more efficient performance and quiet operation. As a general range, a combined furnace and AC unit replacement often runs about $4,000 to $10,000 or more, an air conditioner replacement about $3,000 to $15,000, and in 2026 a full system can run roughly $5,000 to $28,000 nationally, with the final budget depending on system type, energy efficiency ratings, home size, and installation complexity. Total costs can also rise with duct work changes, limited access, or older electrical systems that require more labor, and aging ducts can waste up to 30% of conditioned air and drive up utility bills. HVAC equipment should be installed by a qualified professional, and local code may require permits and duct leakage testing. Before any purchase, a qualified contractor should determine whether the new ac unit is the right match, whether the furnace blower can support it, and whether the manufacturer pairing appears in the AHRI directory, since that helps protect your warranty and avoid a component mismatch. Blower compatibility matters even more with variable-capacity or two-stage equipment, and the outdoor unit’s compressor is also a major cost factor when comparing replacement options. Some homeowners also consider upgrading to a heat pump or dual-fuel setup for better energy efficiency, year-round comfort, and humidity control in summer; a dual-fuel system combines an electric heat pump with a gas furnace and can be a good fit for Hendersonville’s climate.
Our customers can request a free estimate to compare options and available rebates.
Covenant Heating and Cooling is your trusted resource for reliable furnace replacement in Nashville, TN. We are “Dedicated to the Promise of Serving You!” Contact us today.