8 Warning Signs That You Need to Replace Your Air Conditioner

From old age to higher energy costs to funny sounds and smells – know the signs that it’s time to plan to replace your central AC unit.

June 26, 2024

By mid-June, millions of Americans from Atlanta to Louisville to Chicago are running the AC around the clock. You may be, too. But when was the last time you thought about your central air conditioning system’s health?  If you want to stay cool all summer long, pay attention to these 8 warning signs that it may be time for air conditioner replacement. 

Sign #1: Your central AC unit is 10-15 years old

The average lifespan of a central air conditioning unit is 10-15 years. The lifespan will vary depending on how often you run the unit, how well you have maintained it over the years, and the quality of the unit to begin with, among other factors.

For example, the same unit that runs for most of the year in Shreveport might not last as long as the same unit in Indianapolis, which has a longer fall and winter season with cooler to cold temperatures.

Sign #2: Your air conditioner uses R-22 (Freon®)

If your air conditioner uses R-22 refrigerant (aka Freon®), it has two strikes against it. First, it’s at least 15 years old. (The production of new units using R-22 was stopped in 2010). Second, it uses an older refrigerant that’s been phased out due to its harmful effects on the Earth’s atmosphere.

Since R-22 production and importation were phased out in 2020, it’s harder to get and more expensive. Only recycled R-22 is available to service old equipment. Do yourself and the planet a favor and start looking into replacing your older unit with a new, more efficient air conditioner that uses a more sustainable refrigerant.

Sign #3: You’re paying more and more for AC repairs

One of the biggest warning signs of a failing air conditioner is the need for numerous repairs. If air conditioning repair costs are taking a real bite out of your budget, it may be time to replace the AC unit. We’re not talking about one small repair every few years or so. 

If you have an HVAC technician out every summer to make repairs to keep an older system limping along, it may be more cost-effective to opt for HVAC replacement with more efficient units that are covered by warranty.

Visit our Repair or Replace Guide and use the $5,000 rule tool at the top of the page for recommendations. This is an industry-wide recommendation tool.

Sign #4: It’s not cooling your home as well

One of the most common symptoms of a worn-out air conditioner is that it fails to cool your home as well as it once did. Assuming you’re changing your filter as you should and getting professional maintenance, a gradual decrease in efficiency comes with age. 

If you have cool air coming out of the vents but the airflow is not great, it could signal a problem with the blower motor. Decide whether you want to continue with repairs or if it’s time for an upgrade.

Sign #5: Your energy bills are going up

According to the U.S. Energy Information Administration (EIA), air conditioning accounts for anywhere from 12-27% of your monthly power bills, with hot and humid states like Florida and Louisiana on the higher end. If your energy bills are sky-high compared to last year with no big difference in temperature and no huge rate hike from the power company, it’s a warning sign you may need to consider AC replacement. 

Make sure the system has a clean air filter because a dirty filter can cause the system to struggle, resulting in higher energy bills. But if that’s not the culprit and your AC unit is older, it’s not as efficient as it used to be - and that means higher energy bills.

Newer air conditioners are more efficient at cooling and dehumidifying your home - which can save you money on your cooling costs.

Sign #6: Excessive noise

Clicking, screeching, grinding, rattling, or clanking are all indications of a problem with your air conditioner. Turn the system off to prevent damage, and call in a professional to diagnose the problem. It could be that something that has come loose, or there’s another issue. The AC repair costs will depend on what the problem is.

While an HVAC technician can probably resolve the issue, it’s another indication you may want to plan for air conditioner replacement sooner rather than later. 

Sign #7: Unpleasant odors

If you smell a burning odor coming from the air vents when your central air conditioner is running, turn off the system. It can mean the blower motor is overheating. It can also mean an electrical issue. Call to set up HVAC repair.

A musty smell coming from your air vents can indicate mold growth. If your AC unit isn’t dehumidifying as it should, this can lead to mold growth in the air ducts. Mold contamination is a serious issue that you need to resolve quickly.

Sign #8: Frozen coils

A frozen evaporator coil can indicate a dirty coil, blocked air ducts, or a refrigerant leak, which is more common in older units. If your evaporator coil leaks and your AC unit uses R-22, the cost to replace the coil and recharge your unit with more R-22 can be substantial. 

Under these circumstances, it's usually more economical to replace the entire AC unit with a model that uses a more environmentally friendly and affordable refrigerant.

How much does a new AC unit cost?

Your central AC unit cost will vary depending on system capacity, efficiency ratings, and more. For example, the 5-ton AC unit cost will be higher than a 3-ton AC unit because of the capacity to cool a larger home.

Consult with an HVAC company (or more than one) to get specific pricing for your home and your needs.

Consider HVAC system replacement

If you plan to replace an AC unit, you may want to consider a full HVAC system replacement. This is especially true if your furnace is as old or older than your AC unit. Today’s high-tech and high-efficiency air conditioning systems need to be paired with a compatible furnace.

By replacing the entire system now, you save money in the long run - it’s more expensive to replace both units three or so years apart than it is to replace both now.

In addition, to qualify for the energy tax credits, some utility rebates, and manufacturer’s rebates, you may need to install a matched system. These rebates and tax credits can help offset furnace and AC replacement costs, as can 0% APR HVAC financing.

Considering air conditioning replacement?

If you’re considering replacing your air conditioner, be sure to do your homework to find the best central AC unit for your home. By working with your local American Standard dealer, you’re sure to get a high-quality system and expert installation. From Pensacola to Tacoma, you can count on American Standard.

For over 100 years, we’ve designed and manufactured some of the most awarded, well-engineered heating and cooling equipment and earned a reputation for doing things right. 

Browse air conditioners.

Anne Fonda
Content Writer, Trane Technologies


A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need. 

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.  

When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by Mark Woodruff, Senior Product Manager, Ducted Outdoor

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