Air Conditioner Mounted on a WallAre you looking to buy a new air conditioner but need some help picking the right AC unit for your home or apartment?

With so many options out there, from central air conditioning to portable and window AC units, to ductless mini-split systems, and more, it can be hard to figure out how to choose an air conditioner that will work best for your needs.

Fortunately, you’ll find all of the answers in this step-by-step guide.

Below, we’ve compiled the most important details on how to choose the right AC unit that will fit your intended purpose and budget.

After reading this post, you’ll have everything you need for choosing an air conditioner that’s best for you.

How to Choose an Air Conditioner (Step-By-Step)

First things first – the path to picking the right air conditioner involves careful planning and thinking before you make your decision.

For that reason, it’s important to follow some basic steps that will help guide you in that right direction.

When you’re done reading this guide, you should be well equipped to choose the best air conditioning unit that will satisfy your needs and budget.

Now, let’s get into these steps, starting with:

Step 1: Determining Your Budget

The very first thing that you should do when choosing an air conditioner is to determine how much you’ll willing to spend on a cooling unit.

Generally speaking, air conditioners do tend to fall into the category of “pricey household appliances.” However, depending on your budget, you can get a relatively affordable cooling system that can save you money over the long-term.

Your spending power will tell you what type of air conditioners are available to you.

Window Air Conditioners

Window Air ConditionerWindow AC units average between $150 to $300.

These air conditioners are best for people who are looking for the cheapest way to enjoy cold air. They’re intended to cool a single room.

Window units must be installed inside a window but are fairly easy to do. The window mounting bracket and accordion panel are included with purchase and allow you to fit a wide range of window sizes.

Take a look at our list of the best window air conditioner models to see what’s available.

Through-the-Wall Air Conditioners

Through-the-wall Air ConditionerThrough-the-wall AC units average between $400 to $700.

These air conditioners are practically identical to window units but you install them through a wall instead of a window.

Each unit comes with a sleeve that’s used to support the weight of the unit inside the wall.

This type of air conditioner is good for people who want to maintain the use of existing windows while still having a cheap air conditioning system.

Portable Air Conditioners

Portable Air ConditionerPortable AC units average between $250 to $500.

The purpose of a portable air conditioner is to cool a single room. An advantage these units have over window and through-the-wall units is that they can be moved from room to room. However, some versions do require hot air to be vented out a window (or by some other means).

Other models called “ventless” air conditioners don’t require ventilation. You can use these models in any room without having to vent hot air to the outdoors.

Take a look at our list of the best portable air conditioner reviews which shows each of these two versions for different size rooms.

Ductless Mini-Split Air Conditioners

Ductless mini-split air conditioners average between $700 to $2,500.

These AC units are great for anyone who wants air conditioning in a windowless room or can’t install ductwork for a central air conditioning system.

These air conditioners include two parts: an indoor unit and an outdoor unit.

The indoor unit is mounted on a wall and delivers cold air while the outdoor unit powers the system and is mounted on an exterior wall or at ground level.

These AC units can be used to cool a single room or linked together to chill multiple rooms at once.

Central Air Conditioners

Central Air ConditionerCentral air conditioners average between $1,000 to $3500.

Many homes now come with these AC units already installed, however, you can add a new system if one doesn’t exist.

Professional installation is recommended due to the complexity of adding ductwork and proper sizing of the AC unit for the square footage of the home.

The purpose of central air conditioners is to cool an entire house at one time. Cold air runs through ducts that are behind walls and ceilings.

Step 2: Considering Physical and Structural Restrictions

When picking the right air conditioner, it’s important to remember both the physical space afforded to you as well as the structure of the room in which you’ll be installing the unit.

To explain:

Physical Space

Putting an air conditioner that’s too powerful for the room in which it’s placed can cause several issues, all of which stem from the fact that the unit will alternate between cycling on and off way too often.

  • You can experience high levels of humidity in the room
  • The AC unit will consume higher amounts of electricity
  • The frequent switching between cycles can cause early wear-and-tear of your unit’s machinery

On the flip side, if the air conditioner is too small and underpowered for the room, the most obvious problem is that your room won’t be cooled properly. It can also increase energy costs because it must run at full power for longer periods of time.

The best way for how to choose the right size air conditioner is to measure the room you intend to place it in.

Note: This advice is only for window, through-the-wall, portable, and ductless mini-split AC units for single rooms. For ductless mini-splits and central air conditioner systems that will cover multiple rooms or an entire house, professional measurement and installation are recommended.

Choosing Air Conditioner Size

To determine the right size AC unit, all you need is a measuring tape. Then follow these two simple steps:

  1. Measure the room’s width and length in feet
  2. Multiply those two numbers together to get the square footage (sq. ft.)

For example, a 20′ x 30′ room would equal 600 sq. ft. (20 x 30 = 600).

Once you get this figure, you can shop for the right size air conditioner. You’ll just need to do one more step which is to match your square footage with the correct British Thermal Unit (BTU) of the AC unit.

BTUs are a measurement which determines how well the air conditioner can cool a room.

Just remember, the higher the BTU number, the greater the cooling power of the air conditioner.

Below is a quick chart to help guide your decision.

BTU Selection Chart by Room Size

Room Area To Be CooledCapacity Needed
up to 350 sq. ft.8,000 BTU
350 to 400 sq. ft.9,000 BTU
400 to 450 sq. ft.10,000 BTU
450 to 550 sq. ft.12,000 BTU
550 to 700 sq. ft.14,000 BTU

If all you’re looking for is an AC unit to cool a small room, take a look at our best small room air conditioner buying guide. It shows you how to save the most money while picking the best air conditioner among the types listed on this page.

Structural Restrictions

Depending on the type house or apartment you have, there may be certain legal restrictions on the types of air conditioners you may install.

For example, certain residential zones and apartment complexes will not allow you to install window air conditioners because a part of them hangs out a window.

Additionally, you may not be able to install through-wall air conditioners or ductless mini-split systems because it requires structural changes to the walls. However, portable air conditioners are usually allowed since these units don’t hang out windows or need any special installation.

As for central air conditioning, some houses that were not originally built with this system may not be able to handle that type of upgrade due to the structure. Ductwork is required for these air conditioners and the available space may not allow it.

Therefore, if you want cold air inside your home, you’ll have to choose between one of the other types of AC units.

Step 3: Determining Your Short List of Needs

After you’ve figured out your budget and sorted out the possible restrictions you may face with installing the device, it’s now time to answer the big question – what exactly do you need an air conditioner for?

Figuring out what you want from an air conditioner will point you in the right direction when choosing an air conditioner.

Ask yourself these questions to figure out how to choose the right AC unit.

Do you mind heavy installation?

Some air conditioning units like central air conditioners and ductless mini-split systems require extensive installation that has to be performed by professionals, whereas other types require minimal efforts like window air conditioners and portable air conditioners.

Do you want to conserve as much energy as possible?

If energy conservation and saving money on your electric bill is important to you then you’ll want to choose an AC unit that keeps your expenses low. A central air conditioner costs the most to use each month while a window AC unit and through-the-wall air conditioners are the cheapest. Ductless mini-split air conditioners and portable AC units fall in the middle of monthly energy use.

Do you want a unit that can be easily moved?

For some people, having a cooling unit which can be easily moved between rooms is extremely important. The only air conditioner that allows this mobility is a portable air conditioner.

Do you mind a lot of noise?

Does a lot of noise bother you? If so, this can really narrow your search for an AC unit. The decibel scale varies widely in air conditioners. Central air conditioners are the quietest (10dB) and ductless mini-split systems follow (20dB). Window air conditioners and through-the-wall AC units are quite tolerable (50dB) since the noisiest part of the systems are located outdoors or in another room. Portable air conditioners are the loudest (70dB) and can be as loud as a vacuum cleaner.

Step 4: Making The Choice

Now that you’ve learned a bit about air conditioners and asked yourself some preliminary questions, it’s now time to make the final decision on how to choose an air conditioner.

Below, we’ve laid out the different types of air conditioners and how they work best based on the criteria above.

Window Air Conditioners

  • Cheapest option ($150 to $300 with the largest units around $700)
  • Tolerable noise level for most people (around 50 dB)
  • Doesn’t take up any floor space
  • Installation is simple and only requires a window
  • Energy efficient (as little as $20 per month to operate)

If this sounds like what you’re looking for, don’t forget to check out our list of the best window air conditioner models.

Through-Wall Air Conditioners

  • Same advantages as a window air conditioner but a bit pricier ($400 to $700)
  • Doesn’t require a window and can be vented into another room
  • Requires professional installation or someone comfortable with household DIY projects

Portable Air Conditioners

  • Middle of the road pricing ($250 to $500)
  • Noisiest option (around 70dB)
  • Takes up floor space
  • Easiest installation process. Can be up and running in 10 minutes.
  • Can use a window to vent hot air or a number of other portable AC venting options
  • Energy efficient (as little as $20 per month to operate)

If this seems like a good fit, take a look at our list of the best portable air conditioner reviews.

Ductless Mini-Split Air Conditioners

  • Pricey ($700 to $2500)
  • Very quiet (around 20dB)
  • Doesn’t take up floor space
  • Doesn’t require windows
  • Requires professional installation or someone comfortable with household DIY projects
  • Can use in a single room or link several units together to cool multiple rooms at the same time
  • Moderately energy efficient (around $50 to $100 per month to operate)

Central Air Conditioners

  • Most expensive ($1,000 to $3500)
  • Quietest option (around 10dB)
  • Doesn’t take up floor space
  • Doesn’t require windows
  • Requires professional installation
  • Can’t cool a single room. Must cool the entire house at once.
  • Least energy efficient (around $100 to 200 per month to operate)

Well, that about covers it. We hope that this guide helped clear up any questions or doubts you had on how to choose an air conditioner. As you can see, picking the right AC unit for your home or apartment is not as hard as it may seem.

Choosing an air conditioner really just boils down to setting a budget, knowing which options are possible inside your residence, and picking the air conditioner that best meets your expectations.