If your furnace breaks, should you replace your air conditioner too? And if your AC goes out, do you need to replace your furnace as well? This is a common question homeowners ask when they’re faced with a major repair or replacement.
The truth is, there’s no one-size-fits-all answer. You can replace just one unit at a time, but there are several reasons why many homeowners choose to replace both. Let’s look at the pros and cons.
Average Lifespans
Furnace: 15–20 years (sometimes longer if well maintained).
Air conditioner: 12–13 years on average.
Because they age differently, it’s not unusual for one to fail before the other. If your AC is only 10 years old and your furnace suddenly quits, replacing the furnace alone may make sense.
Why Replace Both at Once?
Replacing both systems together is more expensive upfront, but there are advantages:
Efficiency and Performance: HVAC equipment is engineered to work best in matched pairs. For example, a new high-efficiency AC is designed to pair with a specific type of furnace and coil. When you mix old and new, the system can’t perform at peak efficiency. That means higher utility bills over the life of the system.
Shared Parts and Labor: Your AC relies on the furnace’s blower motor to push air through the home. If the blower is weak or worn out, your brand-new AC won’t run as well. Installing both at the same time also avoids duplicate labor costs—like duct transitions and electrical work—that you’d pay twice if you replace them separately.
Warranty Protection: Replacing both units together gives you fresh warranties across the board. If you only replace one, the older system has no warranty coverage and could fail soon after, leaving you with another big bill.
Convenience: No one enjoys having crews in and out of the house multiple times. Doing the full system at once minimizes disruption and gives you peace of mind that both units are the same age, maintained together, and ready for the seasons ahead.
When Replacing One Unit May Make Sense
Not every situation calls for a full replacement. If your AC is fairly new but your furnace is 18 years old, you may choose to just replace the furnace. Budget is another factor—sometimes replacing the broken piece now and planning for the other later is the only realistic option.
As one of our HVAC managers explained on the podcast: it’s a lot like buying new tires. You can replace just one, but most people prefer doing all four at once so they don’t have to worry about the others failing soon after.
What’s Right for You?
Every home and every budget is different. The most important thing is to work with a technician you trust—someone who will explain the repair, replacement, and full system options clearly so you can make the decision that feels right for your family.
If your furnace or AC is giving you trouble, Any Hour Services can help. One of our certified HVAC technicians can inspect your system, walk you through your options, and answer your questions without pressure. Call us today or schedule online to find the solution that works best for you.
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