Is A Window Mounted Air Conditioner More Efficient Than Central Air?

Summer is a fun-filled time of year, marked by cookouts, trips to the beach, and long hours of sunshine. That said, summer can also by a hot and muggy time marked by sunburn and temperatures nearing 100 degrees. And it seems like summer just keeps getting hotter.

Luckily, air conditioning is around to help make us all more comfortable. But, while most folks agree that air conditioning is refreshing, they do not always agree on which solution is the most effective. For instance, some folks prefer a window mounted air conditioner, while others are partial to central air.

Perhaps you assume that central air is the best way to cool down your home. But you may be surprised by some of the benefits of a window mounted air conditioner. Let’s take a closer look at the pros and cons.

Defining Terms

Before we can get into the specifics about the benefits of different air conditioning units, let’s first define some terms.

What is Central Air?

A central air conditioner runs throughout your entire home and usually distributes cool air through vents. Most central air units have a condenser that is kept outside. This is paired with a fan and coil system and ductwork that pushes cool air through your home.

What is a Window Mounted Air Conditioner

A window mounted air conditioner is a type of portable air conditioner that fits into a window. They are often also called “room air conditioners,” as they are often designed to cool a single room.

Benefits of Central Air

Now that we have defined our terms, let’s look at some of the specific benefits of both central air and of a window mounted air conditioner. We’ll start by looking at the best features of central air.

Comfort and Consistency

The biggest benefit that fans of central air conditioning usually cite is the comfort. Since central air operates through ducts and vents that run throughout the building, one unit can cool your entire home.

Additionally, you can easily operate the settings on a central air unit from a single location. This provides a consistent temperature environment in every room of the house. Rather than operating multiple room units, you can just control a single, central one.


A central air unit is also quiet and out of the way. So, when the system is working properly, you almost do not notice it is there.

Another convenient feature of central air is the option of installing a smart thermostat system. With this tool, you can set the air conditioning on a schedule so that it does not run as much when no one is home. This way, you can save money on your energy bill.

Air Filtration

One of the best side benefits of central air conditioning is air filtration. A central air system can help remove allergens like pollen and pet dander from your home. This ensures that the air you are breathing is cleaner.

Drawbacks of Central Air

While there are many benefits to central air, it also has its negative features. You should consider these factors before installing a system.


Without a doubt, the biggest drawback of central air is the cost. It can be extremely expensive to have an old unit replaced with a newer, more efficient unit. And, if you need to have central air installed in a home that does not have it, the installation will be even more expensive.

In some older homes, ducts for central air do not exist, because central air was not available at the time the home was built. In some cases, it is impossible to have central air installed at all. When the installation is possible, it is a complicated and costly project.


Central air is not only expensive to install and expensive to replace. It can also be expensive to fix. Additionally, it is difficult to learn how to fix your central air unit yourself. By contrast, since window units are so inexpensive, it is fairly easy to simply buy a new one if it breaks.

Benefits of a Window Mounted Air Conditioner

Now that we’ve considered some of the benefits and drawbacks of central air, let’s take a closer look at window units. There are many situations where a window unit might be better for you.


A window unit is a great option for folks who don’t have the option of installing central air. For instance, if you are renting a home, it isn’t necessarily up to you whether to install an air conditioner.

Luckily, you can easily set up a window unit without your landlord’s permission. And, when your lease is up, you can decide to take your window unit with you to your next home.

Easy Installation

Another great feature of a window unit is that you do not need a certification in HVAC to set one up. Simply put the unit in the window and plug it in! Most window units plug in directly to a standard outlet and need no special setup.

Use Less Energy

A window unit is much smaller than a central air conditioning system and cools a much smaller area. For this reason, these units use much less energy and are less expensive to run. So, if you do not need your entire house cool, they can be a cheaper option.

Drawbacks of a Window Mounted Air Conditioner

As we’ve seen, window units do have several positives. Let’s take a closer look at some of the drawbacks they have.

Lack of Circulation

Central air units have vents throughout the home that push out cold air. This helps the air to circulate better.

By contrast, a window unit pushes out cold air on one spot. This can create an effect where the area right in front of the unit is cold, but the area around it is stuffy.

A fairly easy fix for this problem is a ceiling fan. A fan will help better circulate the cold air generated by a window unit.

Limited Cooling

Window units are often also called room air conditioners because they only cool one room. So, if you have multiple rooms that need to be cooled in your home, you will need multiple units. This can get expensive and frustrating.

So Which is More Efficient, Anyway?

When it comes to choosing an air conditioner, one of the biggest concerns for most users is energy efficiency. Running an air conditioning unit is a huge expense. After all, air conditioning costs Americans $29 billion a year and accounts for 6% of all energy usage.

The more efficient your air conditioner is, the bigger savings you will see on your utility bill. Also, energy efficient air conditioners are better for the environment.

So if efficiency is your top priority, should you get central air, or a wall mounted air conditioner? The truth is that the jury is still out on this one, and there are good arguments for both.

The Case for Central Air

Many assume that central air is always more efficient. This is partly because central air cools the whole house at the same time, and partly because central air is seen as more modern.

But while central air can be more efficient, it really depends on what kind of system you have. For instance, if you have an old central air unit from the 70s or 80, chances are that it is using up a lot of energy. This is both because units were not made as efficiently back then and because the system is likely worn down.

Of course, if you replace your vintage central air unit with an updated one, it likely will be quite efficient. Air conditioning units are rated on a seasonal energy efficiency ratio (SEER), so look for a system when a high rating if you plan on updating yours.

The other feature that can make central air more efficient is dehumidifying. Remember that air conditioning does not just make air feel cooler–it also removes moisture from it.

Because central air affects a larger volume of air, it can remove more moisture more quickly. If you’ve ever complained about the temperature on a hot day, you might have heard someone say, “It’s not the heat, it’s the humidity.” Since central air can remove so much moisture, it can provide more relief without having to set the temperature to the coolest level.

Can Window Mounted Air Conditioners be More Efficient?

While there are many arguments for central air’s efficiency, there are some cases where a window mounted air conditioner might be the better choice. For instance, if you live in an area that doesn’t get very hot in the summer, a window unit might provide all the relief you need.

This way, you can choose to cool just the room you sleep in, instead of cooling the whole house. This is especially convenient if you live alone or live with just a spouse, and don’t need your entire home cool at night.

Also, central air units can sometimes lose efficiency through what is called “duct loss.” Basically, as cool air passes through the ducts in your home, it starts gaining heat, so it is not as cool by the time it gets to you. Since a window mounted air conditioner blows on you directly, it does not have the same problem.

We mentioned earlier that central air is very convenient and almost invisible. While this can be an attractive feature, it can also lead to overuse and energy waste. Because of the physical presence and noise that a window mounted air conditioner brings, you will rarely forget to turn it off or turn it down when necessary.

The bottom line is that if you do not need your entire home cool all the time, then a window mounted air conditioner is a better option. This is because you can target the cooling to the areas of your home that need it, rather than applying cool air to the whole house indiscriminately.

Combing Central Air and Window Units

Believe it or not, some folks have found that the most energy-efficient option is to have both a central air system and a window mounted air conditioner. Of course, this solution only saves money and energy if both systems are not constantly running. Here’s how it would work.

Let’s say you have an older central air system that is not very efficient. To update the system would be very expensive–anywhere from $5,000 to $15,000. It would take years for the savings on the energy bill to pay off the cost of the upgrade.

On the other hand, not upgrading the unit is also expensive. Because the system has to constantly run to keep your home at the desired temperature, it uses up a lot of energy and electricity.

If you live by yourself, or it is just you and your spouse at home, you could address this issue by putting a window unit in the bedroom. This way, you could run the central air during the day. But then, for 6-8 hours at night, you could just run the window mounted air conditioner in your room.

With this approach, you would still cool the whole house during the day. But then, at night, when you do not need the whole house cool, you will not have to pay to keep the whole house cool. By turning off the central air for eight hours of day, you could see significant savings on your electric bill.

Choosing the Right Air Conditioner for You

Ultimately, when deciding whether central air or a window mounted air conditioner is better, the answer is a resounding, “It depends.” To get the best air conditioning system for your home or business, you’ll need to evaluate the needs of your space and the constraints of your budget.

That said, if you’ve decided that you would like the more flexible option of a window mounted air conditioner, then you have come to the right place. Check out our latest AC unit reviews to find the best equipment for your needs.

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