When to Replace Your Air Conditioner: 3 Rules Of Thumb

“Is it time to replace my air conditioner?” This is a question that plagues many homeowners.

Air conditioners, unlike some other household items, don’t just stop working overnight. Instead, they degrade slowly, leaving you in a grey area about when exactly to invest in a new unit.

To help the decision-making, rules like ‘replace it after 10 years’ exist. But are they genuine? 

I found that most rules on the internet are constructed by the HVAC industry to sell you a new air conditioner way too early.

In this article, I’ll show you 3 rules of thumb you can trust that help you decide whether to replace your air conditioner or not!

Let’s have a look:

Rule 1: Take HVAC Industry Advice with a Grain of Salt

First of all, take any advice you read on HVAC websites with a grain of salt. Usually, they try to sell you a new air conditioning system you don’t need.

You’ll find all kinds of different advice online, ranging from the 10-year rule to repair cost-based rules.

The fundamental problem: Rules like the 10-year replacement rule are all arbitrary and made up by the HVAC industry.

Air conditioners don’t suddenly become inefficient after 10 years. Also, their repair cost does not necessarily increase over the years.

One interesting rule put out by HVAC companies is the $5,000 rule. According to the $5,000 rule, you should replace your air conditioner if yearly maintenance & repair costs multiplied by the age of the air conditioner in years surpass $5,000.

The fundamental problem with this rule is that age is a factor. The older your air conditioner gets, the more pressing the replacement gets, according to the rule. No matter how little the maintenance cost and how well your unit works, at some point replacement will be necessary according to the rule.

That’s obviously not true.

Always keep in mind: Take HVAC industry advice with a grain of salt.

Rule 2: Never Replace a Working Unit

There is no reason to replace a working air conditioner. No matter what the HVAC industry tells you, getting a new air conditioner is always going to be more expensive than running your old unit.

Old unit maintenance & repairs are economical. Usually, old units require

  • refrigerant refills
  • filter replacement & coil cleaning
  • compressor or power supply fixing in case of errors

These are all standard tasks for a technician. Their scope is limited and they can be done within a day. Basic maintenance doesn’t get more expensive over time.

Getting a new air conditioner unit, however, requires:

  • consultation for the new system
  • labor intense installation
  • disposal of the old unit
  • a large monetary investment
  • ductwork evaluation
  • potential electrical upgrades

And the list continues. Expenses for a new air conditioner unit are not limited in scope. They can get arbitrarily large, depending on your home’s electric circuitry and ductwork. Getting a new air conditioner potentially blows up into a never-ending stream of tasks to be done.

And that’s precisely why air conditioner replacement is so profitable for HVAC companies.

Always remember: Never replace a working unit.

Rule 3: Don’t Speculate, Wait Instead

Our governments create new laws daily.

In 2020, for example, the US government prohibited the production and import of new R22 refrigerant. R22 refrigerant was predominantly used in old air conditioners. From 2010 onwards, new air conditioners are prohibited to run with R22.

If you still run an old R22-based air conditioner, don’t panic.

It is not prohibited to continue running your old air conditioner. It’s just illegal to recharge it with R22 refrigerant. And possibly the refrigerant in your air conditioner lasts another few years.

That’s plenty of time to save money.

The most cost-effective way to handle changes in laws, local rules, or technology is almost always to wait.

Likely, your air conditioner lasts a lot longer than you expected. And possibly laws change while you wait. Keep your air conditioner as long as it’s working. Don’t jump at the news!

Always remember: Don’t speculate, wait instead.

Is Air Conditioner Replacement worth it for better efficiency?

It’s important to remember that while restoring comfort is a priority, efficiency shouldn’t be overlooked.

Since 1987, federal standards for air conditioners have evolved, setting the bar at SEER 10, then raising it to SEER 13 in 2006.

Today, for an air conditioner to meet ENERGY STAR® specifications, it must boast a SEER rating of 14.5 or higher and an EER of 12 or more.

Replacing the entire system, or parts of it, offers an opportunity to not only restore comfort but also improve energy efficiency, potentially reducing cooling costs.

But how do you navigate this maze of considerations to make an informed choice?

That’s where many HVAC companies start creating unnecessarily complex rules.

Usually, the answer is simple:

The running cost of an air conditioner is far too low to justify replacing a working unit.

Air conditioners were already energy efficient 20 years ago. Even old air conditioners have rather low running costs.

Your energy savings through replacing air conditioners will be somewhere between $25 – $50 per month, depending on where you live and your usage.

Would that justify expenses up to $10,000?

Also, shift your thinking:

You can only make such a large purchase once every other decade. The more you delay air conditioner replacement, the better the new air conditioner will be due to energy efficiency improvements.

A new air conditioner in 2-3 years is even more efficient than a new air conditioner now.

In most cases, running your old air conditioner as long as possible saves you the most money.

Case study: Energy Savings after Replacement

The U.S. Department of Energy estimates the following yearly energy savings for 15 SEER vs 13 SEER air conditioners in different climate zones:

ClimateYearly Electricity Cost Savings (15 SEER vs 13 SEER)

Note that these are yearly savings. My conclusion:

Replacing air conditioners for increased efficiency is not worth it.


Replace your air conditioner only when it is absolutely necessary, e.g. when your air conditioner is irreparable, your electricity cost is way too high, or because of a change in law you can’t circumvent.

As long as your air conditioning unit works, keep it.

Maintenance & repair cost is limited, while a new unit with installation can turn into a money pit.

Don’t fall for HVAC companies & posts online spreading fear and uncertainty. Their job is to sell you a new air conditioner.

Use your air conditioner while it’s still working. Even if it’s not the most efficient device.