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Here’s when to replace your air conditioner

It can be tricky to know exactly when your air conditioner should be replaced and what your best and most efficient options are for replacement. Here’s what you need to know.

It can be tricky to know exactly when your air conditioner should be replaced and what your best and most efficient options are for replacement. Here’s what you need to know.

Whether you’re updating your unit or installing an air conditioner for the first time, in this guide we’ll dive into AC technology, how to know you need to replace your unit, as well as replacement options to consider—including ductless air conditioners and portable air conditioners.

Here are the signs you need to fix (or replace) your air conditioner

  • It isn’t cooling your home well.
  • Your AC runs too long each time it turns on.
  • It makes unpleasant noises.
  • Your unit is leaking moisture.
  • Your utility bills keep going up.
  • You have concerns about air quality.

Let’s look at the specifics of each one, so you know what to look for. 

It isn’t cooling your home well

We’ll start with the obvious. If your air conditioner is running but your home isn’t getting cooler, something’s gone wrong. Another common problem: Your air conditioner is pumping out air, but it just isn’t very cold. Either way, your home is uncomfortable—and there’s clearly an issue to address.

Your AC runs too long each time it turns on

When your AC turns on, it should only run about 15–20 minutes before shutting off again.  If it’s running any longer than that—or if it seems to run constantly on hot summer days—then something isn’t working correctly.

It makes unpleasant noises

If your air conditioning unit begins making strange noises, such as squeaking or grinding or screeching, you shouldn’t ignore it. While some unpleasant noises are the signs of easily fixable (and relatively harmless) problems, other sounds—such as a high-pitched screeching sound—can be the sign of a potentially dangerous malfunction.

Your unit is leaking moisture

Some air conditioners (especially window units) drip water here and there. It’s normal. But if you begin to see significantly more water, it’s time to call a technician. If the dripping is coming from a significant accumulation of ice on your AC coils, it could be a sign of leaking refrigerant—which is a health and environmental hazard and nothing to mess around with. 

If your air conditioner seems to be fine but your electric bill gets more expensive every summer, you may need to call a technician out to assess your unit.

Your electricity bills keep going up

If your air conditioner seems to be fine but your electric bill gets more expensive every summer, you may need to call a technician out to assess your unit. Air conditioners can lose efficiency without any obvious signs, and there may be hidden problems affecting your system.

You have concerns about air quality

If you’ve been coughing a lot lately, you may want to check out your HVAC system. Dust particles and mold spores can get inside your ductwork and circulate inside your home whenever air is flowing. (And if you haven’t been regularly replacing your unit’s air filters, the problem could be an even greater concern.)

A wall air conditioner, powered by heat pump technology, can be 3x more efficient than traditional AC, as well as much quieter.

What are the alternatives to replacing your air conditioner, including ductless and portable air conditioners?

Before we talk about replacement options, let’s talk about a few steps you might take before deciding to replace your air conditioning unit altogether.

First, you should know that regular maintenance can keep your air conditioner running for a long time. If you suspect that something is wrong with your air conditioner and you haven’t had a pro take a look, definitely do that before deciding to replace it. The issue could be a simple fix. HVAC experts also recommend that you get your air conditioner checked out by a professional at least once a year—right before summer starts is the perfect time. (And if you have a ductless air conditioner system or use a portable air conditioner, it’ll need regular maintenance as well.)

If your air conditioner system is working properly but your home still isn’t comfortable, you have a couple of options:

  1. Supplement your main air conditioning system with smaller air conditioners in “hot spots.”
    It might seem counterintuitive, but sometimes two air conditioners can be more energy-efficient than one—especially if your main AC is struggling to cool the entire house. Supporting your main AC system with additional portable or window units works particularly well if there are just one or two stuffy rooms in your house (or if you have a multi-story home with only one thermostat).
  2. Fix your house instead of your air conditioning.
    It doesn’t matter how hard your air conditioner works if your home is letting all the cold air out, so sealing and properly insulating your home can make a huge difference in the efficiency of your air conditioning system. (And if you live in an eligible area, you may be able to get this work done for no upfront cost.)

    Learn about types of insulation in the Sealed Guide to Insulation.

What are my air conditioning options?

You’ve decided that your plan includes a new AC unit. So which kind is best for your home? Let’s look at your options and how they compare with each other.

Window units

Window units are small air conditioners that you install—you guessed it—in a window. Most likely, you’ve seen them before. They’re self-contained units; you won’t need to hook them up to any larger system, which means installation is pretty simple and some people even choose to do it on their own. Don’t hesitate to hire a pro, though. Window units are heavy and installing them is a two-person job. (Also, be sure to get accurate measurements of your window before you purchase your unit.)

If you find yourself wondering how many window units you’d need to make your home comfortable, there’s a good chance that window units aren’t the right solution for your home at all.

Advantages and disadvantages of window air conditioning units

Window units are inexpensive and relatively simple to install, so they’re a popular choice for those for whom installing a more comprehensive cooling system doesn’t make sense (such as renters or those who own a unit in an older building). They’re also useful as a supplement to your central AC (or if you just need to cool a smaller corner of your house).

But window units are only designed to be effective in smaller spaces and definitely aren’t a good comprehensive cooling solution for an entire house. In short, if you find yourself wondering how many window units you’d need to make your home comfortable, there’s a good chance that window units aren’t the right solution for your home at all.

Cost of window air conditioning units

Window-mounted air conditioning units generally cost between $150–500 each, depending on the features and brand you select. You should also plan for the costs of additional mounting hardware (to ensure your unit fits properly in your window) and professional installation (if screwdrivers aren’t your thing).

Portable air conditioning units

Portable air conditioners are stand-alone cooling units that don’t require a window installation, so they’re popular for people who have a small area to cool and don’t want to install an appliance in their window. To run one, you’ll need a power source and a place to vent the moisture via hose (usually a slightly-opened window).

Advantages and disadvantages of portable air conditioning units

The biggest benefit of these units is their flexibility—they’re easy to install in any room that has a power source and a place to vent the liquid condensation. You can even move the same unit from room to room, if absolutely necessary (although they’re pretty heavy and you’ll have to re-install the condensation hose every time you change location). However, portable air conditioning units provide the least cooling power for your dollar. They’ll provide better cooling than a fan, but they won’t get your space as comfortable as any of the other options on our list. They’re also pretty cumbersome and tend to get in the way of daily activities.

In other words, you should think of a portable air conditioner as a last-resort option. You should only get one if none of the other options are feasible.

Cost of portable air conditioning units

Plan to spend at least $200–300 for a portable air conditioner (though high-end units can cost thousands of dollars).

Traditional central air conditioning

This is the option most people think of when they think of air conditioning. A traditional air conditioning system comes in two major varieties: a split-system and a packaged unit.

A split-system air conditioning system has two main components: an outdoor condensing unit and an indoor evaporator unit (which is often combined with a heating solution, such as a furnace or the indoor part of a heat pump).

A packaged unit bundles all the components—condenser, compressor and evaporator—together in one outdoor cabinet (which can also include a heating system).

Both systems distribute air throughout your home via ductwork.

Advantages and disadvantages of traditional air conditioning

Compared to window and portable units, central air conditioning is quieter, more convenient and more efficient—not to mention more comfortable. The new central air systems don’t need much maintenance and many people prefer a cooling system with a low visual profile—you won’t need to install any bulky wall or window units. All told, traditional central air conditioning is well-loved by many Americans and it’s certainly a viable cooling option—especially if your home is well-insulated and sealed.

However, when compared to greener, smarter technologies like the heat pump, traditional central AC can fall a bit short. For one thing, it requires ductwork—if you don’t have ductwork, you can’t have central air. It’s not nearly as energy-efficient as a heat pump. And a traditional air conditioning unit only does one job: cooling. If you also need a heating option, you’ll need to purchase and maintain a separate system.

Cost of installing a central air conditioning system

The cost of a traditional air condition system varies widely—it depends on the size and structure of your home, where you are in the country, and whether you need to install or repair ductwork. In general, though, you’ll need to set aside between $5,000–15,000, typically paid upfront and out-of-pocket.

Heat pumps (also known as ductless air conditioners or mini-split AC)

Heat pumps are the smartest, most efficient cooling option currently on the market. Don’t let the word “heat” fool you—they earned the name because of how they work: Heat pumps cool your home by removing heat from your indoor environment and transferring it outside your home. (And, conveniently, they also heat your home by reversing the process: taking heat from the outside air and moving it inside your home. So they’re an air conditioner and a heating system—a complete two-in-one solution.)


Heat pumps take hot air out of your house in the summer, leaving cool, fresh air behind, without using much power to operate.

Heat pumps are flexible technology. They come in several varieties, and you can get them in both ducted and ductless versions—so if you’re looking for an efficient ductless air conditioner, this is your best option.

Ducted heat pumps or central heat pumps use a similar configuration as a traditional central air conditioning unit (so you can use your existing ductwork, if you have it). Ductless heat pumps—also sometimes called ductless air conditioners or mini-split air conditioners—use small, wall-mounted units called mini-splits to condition and distribute the air. The mini-split units are directly connected to an outdoor unit via refrigerant lines—so no ducts are required.

Unlike traditional air conditioning, heat pumps also heat and dehumidify your home. No need to purchase a separate heat system.

Advantages and disadvantages of air conditioning with a heat pump

Heat pumps are incredibly energy-efficient—they’re the greenest option currently on the market—and they’re quickly becoming the new standard in American HVAC. They make your home feel great, with plenty of cool, filtered airflow at all times. And, unlike traditional air conditioning, heat pumps also heat and dehumidify your home. No need to purchase a separate heat system.

For most people, heat pumps provide the best comfort and lifetime value, so the biggest barrier to heat pumps is usually the upfront expense of installation. (And if you want a ductless system, the look of the mini-splits on your walls can take a bit of adjustment.)

Can a heat pump replace your air conditioner?

Yes! For many households, a heat pump is the best option—whether you have existing ductwork or not. Heat pumps condition the air efficiently and, because they’re designed to provide continuous airflow, your house will feel fresh and cool 24/7. No more stuffiness.

Cost of installing a heat pump system

Costs vary by region, but installing a complete heat pump system can run you about the same amount of money as installing both a heating and central air system at the same time. However, that isn’t unreasonable when you consider that you are, in fact, getting both heating and air conditioning in one system. And when you consider the superior comfort and energy-efficiency of a heat pump, it’s a technology with an excellent lifetime value.

Also, if you live in an eligible area, you can get a heat pump installed at no upfront cost. You’ll pay only with the money you save on energy. (And if you don’t use less energy, you don’t have to pay.)

September 8, 2020