How To Choose A Window Air Conditioner: Complete Guide

How To Choose A Window Air Conditioner: Complete Guide

Have you survived the last summer without any air conditioner and you don’t want to risk this torture again? Maybe it’s time to start to find a way how to choose a window air conditioner. It won’t be easy because we will have to face lots of parameters and aspects and we will also calculate our monthly cost when the unit is operating. But this ultimate guide gives you a perfect overview of the overall costs, available features and many other things that can affect your choice.

If you are still wondering about the purchase of a window AC unit this article helps you to do the final step. We boiled down all the important information. Keep reading!

Benefits of a Window Air Conditioner

Many people desire to have a central air conditioner but the layout of the house or their financial situation won’t allow them to install the central system. If you belong to this group of people you will appreciate the window appliance. It has lots of benefits that help you to enjoy the comfort of cool home every summer season.


One of the biggest benefits is its affordability. However, you are not a billionaire you can buy a new window air conditioner unit. The starting price for a new unit is between $150 and $2000. If you decide to buy a used one the price could be better and the appliance can still provide seasons of very nice comfort. Of course, if you will take care of it properly.

The price is dependent on many factors such as brand, energy efficiency, features, etc and of course it affects your decision on how to choose a window air conditioner. If you are on a budget and can’t spend lots of money you will be satisfied with the cheapest model, however, you won’t be able to enjoy useful features. But the main purpose is kept even in the cheapest units. You will survive the heatwaves during the summer months.

Easy Installation

You have maybe heard the installation is very easy. And it’s absolutely true! It’s easy and cheap. You don’t need any special tools to build in the appliance. The only tool you need is a screwdriver. Additional things that are used during the installation are a part of a package with your new unit.

Since you can do it on your own you don’t pay for customer service and a team of experts. The only thing you have to do is to follow instructions given by a manufacturer and also read or watch some very good manuals on the internet. The installation will be much easier than you think.

Of course, among the wide range of models and brands, there are some differences and the units are offered with different accessories for the installation process. So, you should be prepared for it and read some tips and tricks before you will start to do it. If you can see in some internet manual that a very good feature for the installation is a weatherstrip and you will realize that your model isn’t provided with it you can buy it before the process of installation. Don’t underestimate this step and be prepared for it!

Cheap Operating

The starting price is one thing but you have to take into consideration another aspect which is the monthly operating cost. Every month you run your window air conditioner you will have to pay for electric energy.

Since the window air conditioner is designed to cool down one room your bills won’t skyrocket. Nevertheless, it’s better to know how much you are going to spend every month in a season.

If you want to know the consumption of your appliance in advance you can do a quick calculation. To do this calculation you need these parameters:

  • How many Watts your unit consumes.
  • A price for kilowatts per hour given by your electric company.
  • A number of hours you want to operate your appliance every day.

Monthly Cost Calculation Formula

Watts x 1 (hour of use) ÷ 1,000 x Price given by your electric company (kWH) = hourly cost of operation

Example of Calculation (Considering Average Price $0.1241/kWh for State Alabama):

  • (500 Watt unit x 1-hour ÷ 1,000) x 0.1241 (kWH) = $0.06205 Cost of operating for one hour
  • $0.06205 x 8 hours per day = $0.4964 Daily cost of operating
  • $0.4964 x 30 days in a month = $14.892 Monthly costs of operation a window AC unit

The example above shows that the price of the monthly cost is $14.892. It’s almost $15 which is awesome. Operating the unit costs a few tens of dollars every month. Use the calculating formula above and use it for a machine you would want to buy. This helps you decide how to choose a window air conditioner and it’s not rocket science.

Cheap Maintenance

Compared to central air conditioners the window units are easy and cheap to maintain. The regular maintenance could be done by homeowners before and after the season. It’s required to have any special tools. You need only hot water, a brush, kitchen soap, and a rag.

Besides the regular maintenance, you can face some special cases of maintenances. If you meet them you will have to probably pay for professional help. These special cases include e.g. motor lubrication, replacement of fan belt, the addition of refrigerant level, etc. These situations are rare (and maybe you won’t deal with them for the long life of your unit) but you should be prepared for them. Why? Because they are the additional costs.

Cooling One Room

One of the biggest advantages of a window air conditioner is that you can cool only space you really use. The truth is that the central conditioning system cools down the entire home. It means your system consumes the energy to make comfort in every room of a house even in rooms that are not used. For many of us, it’s wasting money and energy.

The best compromise is to buy a window AC unit. It could be used only in one room. You usually operate the device in a room used the most. People who spend most of their time in a living and know they will have lots of visits they install the unit there. The same is when you desire to feel comfortable during sleep.

You should know which room you would like to use. It’s crucial for choosing the right unit and avoiding picking a weak or too much strong one. Once, you are sure which room is the perfect one you can measure the square footage of the room to find the unit which is appropriate.


Don’t expect portability in sense like a portable air conditioner. A window air conditioner has a different level of portability.

A standard window air conditioner is an appliance that requires the installation and then it stays in one place. According to instructions from the manufacturer, you should the unit reinstall after every season and store it in a well-ventilated and dry place. You don’t need to be worried in winter because your window stays closed.

Another kind of portability the unit provides when you rent an apartment or a dorm. You can install the machine in a window and when your contract is over you simply reinstall it and take it with. There is no need to buy a new window AC unit and spend money. And for many of us, it’s a great argument of why and how to choose a window air conditioner.

Disadvantages of a Window Air Conditioner

As everything in our lives also a window air conditioner has some disadvantages. You should take these negative properties into consideration before you purchase a new machine. They are very important and you will maybe realize that they are so crucial you can’t get over them and you will decide on a different kind of air conditioner.

Don’t overlook the disadvantages and take a closer look at them for a better understanding of how much they can affect your choice.

Reinstallation After Season

According to instructions given by producers of the major vast models, you should reinstall your appliance after the season, do the after-season maintenance, and store your unit. The best place where to store your unit in a dry and well-ventilated place usually attic, basement, or a big closet in a bedroom. Try to avoid wet places like a garage where your unit will be exposed to rodents or insects desiring to find shelter inside.

There are lots of people who can’t reinstall the unit for a winter season for some reason. Somebody doesn’t want to do the process of installation every year, somebody doesn’t have a place where to store it, etc. For this situation, you can buy a window air conditioner cover suitable for your model. There are many versions made from different materials. They work on the same principle. You have to slip the cover on the outer part of your unit and fasten it by using a drawcord string.

Hot and Cold Spots

If you decide to buy a window air conditioner you will definitely face hot and cold spots in a room. They are caused by worse airflow since the air is sucked in and out in one place of the room. There are no system of ducts built-in a floor and ceiling.

Many people hadn’t known about this fact before they purchased the machine. Some people can accept this fact and some no. You should consider this disadvantage in advance.

Factors Affecting Price and Your Comfort

You are maybe wondering how is it possible your brother paid for his window air conditioner unit about $100 and your co-worker has an appliance for over $500? What is the difference between these two units?

There are many factors affecting the overall costs along with your comfort. You should take them all into consideration because they can significantly affect not only the starting price but also the use and monthly costs. If you underestimate these factors you can easily end up with a cheap unit which consumes lots of energy every month or is too noisy.

Read about the factors very carefully and you will find out how to choose a window air conditioner properly.

Starting Cost

The starting price can vary from $100 up to over $2000. However, it’s cheaper than installing the central conditioning system it’s better to think about the price and don’t underestimate many things.

The main differences that occur are caused by the space you want to use the unit for. Of course, if you need a window air conditioner for a very small bedroom its price will be smaller compared to a machine that has to cool down a very large living room and kitchen. According to space in square footage, you can identify the BTU (British Thermal Unit). Higher BTU indicates a higher price tag.

The appliances are sold with lots of functions and it’s up to you if you’d be happy with some of them or if they make your life easier. Many of the special functions like sleeping mode, remote control, or programmable timer save energy and your effort.

The starting cost is also affected by the energy rating of the unit. The most energy every month is consumed by air conditioners that cool or heat up your home. Therefore, the goal is to find the machine with a high energy rating and pay a little bit more than to accept a low energy rating and spend a lot of money every month for the energy bills. Check out the most energy-efficient window air conditioners.


If you’re not sure about how to choose a window air conditioner your first steps should be in measuring the size of a room you need the AC unit for. Why? Because it’s crucial for defining the BTU (British Thermal Unit) that indicates how much energy you need to raise the temperature.

If you do not measure the room you won’t be able to define the appropriate BTU. Then, your new window AC unit can be too strong or too weak to cool your home.

To find the most efficient model you have to measure the room in square footage and then choose the appropriate BTU from the table below.

BTURoom Size
5,000 BTU150 sq. ft.
6,000 BTU250 sq. ft.
7,000 BTU300 sq. ft.
8,000 BTU350 sq. ft.
9,000 BTU400 sq. ft.
10,000 BTU450 sq. ft.
12,000 BTU550 sq. ft.
14,000 BTU700 sq. ft.
18,000 BTU1,000 sq. ft.
21,000 BTU1,200 sq. ft.
23,000 BTU1,400 sq. ft.
25,000 BTU1,600 sq. ft.
28,000 BTU1,900 sq. ft.
36,000 BTU2,700 sq. ft.

This table should give a great overview of how to find the right BTU for your home. If your room is dissected try to cut the room for small pieces like rectangles, squares, and triangles. Measure every piece and add them together. In the case, you have a very large room – read my review about the best window air conditioners for large rooms. Where you can find which suits you best.

Energy Efficiency

In general, the window air conditioner consumes lots of energy. On average one-half of the energy bills are paid for the operating of the AC unit regardless of a type or a model. The biggest advantage of window units is they are designed to cool only one room, not the entire house. Therefore, the bills won’t skyrocket. The energy efficiency is a very important aspect of our ultimate how to choose a window air conditioner guide.

However, consumption is still crucial and you should focus on choosing a model with Energy Star Certification. Some models are offered with Energy Efficiency Ratio (EER). The higher EER indicates saving energy. Of course, you will have to pay for this rating a bigger amount of money but it’s your long term investment because it’ll save money for energy bills in the future.

There are also some available features that help you to save energy. For example the programmable timer or sleeping mode. If you’re interested in these features read about them below.


The window air conditioners aren’t the quietest units ever. They are supposed to be noisy. If you buy the unit to be installed in your bedroom, living room, or in an office you can maybe struggle with a noisy operating. For those who want to breathe cool air during sleep or having a meeting with clients, the window air conditioner could be a bad choice.

On the other hand, there are thousands of people who are not so sensitive and they have no problem with the noise. If you decide on this unit and know about your troubles with the noise you should focus on choosing a model with a good reputation for being quite. Read my reviews about the quietest window air conditioner even for your bedroom. Written by homeowners who bought the product before you and you can’t be wrong.

Window type

Some people want to install the window air conditioner through the wall but it’s not a good idea. If you really need the through-the-wall appliance you should count on this type of AC unit. The window AC models should be strictly installed in a window and you should know how to choose a window air conditioner.

Before you buy a window air conditioner you have to not only measure the room but also the window. If not you can struggle with a big problem when your machine will be larger than the window.

The electrical cord could cause also another problem. Before you choose the window in a room be sure the outlet is close to this window. The electrical cord isn’t usually long and you need to plug your appliance.


There are a lot of manufacturers producing the window air conditioners. Since many models are cheap almost everybody can invest money and buy a new machine.

Well-known brands and manufacturers produce high-quality models with very well options for customer services. The major vast of the AC units is designed to be operated for two years without having to face any technical problem. If you don’t underestimate the pre and post-season maintenance you can count on a longer life.

Electrical Circuit

This factor affects additional costs. If you don’t know the window air conditioner could cause an issue in your electrical circuit at home. We know many cases when the homeowners realized that the window AC unit overloaded the circuit. The possible consequences could be tripping a circuit breaker or blowing a fuse. It could make lots of troubles because people tend to underestimate this issue.

There are two solutions. The first one doesn’t cost money but it could be more complicated to realize it. You have to find out what else is connected to the same circuit as the window AC is. Then, you should unplug all of the electrical devices and the only appliance plugged in should be a window unit. It could be complicated when the same circuit is shared by devices that need to be plug permanently like a fridge.

Your second solution doesn’t influence the rest of your devices at home but it influences your bank account. You have to hire an expert with electrical skills who will be able to build up a new circuit just for the window AC unit. This additional cost is about $150 (depending on a state where you live).


Since the purchase of a window air conditioner could be a big investment for you it’s better to think about that very carefully. Sometimes you can count on a not-proved producer and then end up with an appliance that couldn’t be fixed.

The best way is to rely on reliable brands. Read reviews provided by homeowners who bought the units before you. They share the best tips and help you find the best producers.

Another good tip is to pick a brand offering a very good net of customer services.

Available Features You Will Appreciate

Even the basic models of window AC units provide you some very interesting functions you will love a lot. These functions have amazing magic served with a big portion of comfort, saving energy, and cool air. Once, you will try them you won’t want to live without them and their services.

The functions are dependent on a brand and model you choose to buy. Some units offer the same function but you can reveal the use is different because they could be limited somehow. Follow our tips in order to know how to choose a window air conditioner. Or just simply pick one of the best smart window air conditioners.

Programmable Timer

You will definitely appreciate the function of a programmable timer when you love to come home and enjoy the cooled room without having to deal with heat accumulated after a very hot day.

The timer could be usually set in one-hour intervals up to 24 hours before it turns on or off automatically if you buy a more expensive device. The cheap window air conditioners usually allow you to set 2, 4, 8, 12 hours before they are switched off.

Even the cheap appliances offer you pretty decent comfort while you’re not home. This function is definitely worth!

Sleeping Mode

The sleeping mode works on a principle of pleasant sleeping during the entire night until you wake up. Our body needs a lower level of cooling when we’re dreaming. An air conditioner regulates the room temperature by 0.5 to 1 degree per hour, up to a maximum of +3 degrees depending on your machine. This process of slowly changing temperature allows you to sleep in better comfort and helps you significantly to wake up.

We think it’s not needed to mention the sleeping mode saves energy a lot. Also, you won’t struggle with the feeling of having a dry throat after waking up.

Air Filter Alert

This feature is amazing especially if you are not able to keep deadlines. We tend to forget about things that should be done regularly.

The mast majority of air filters are washable and they should be cleaned every two or three weeks by using a kitchen soap, hot water, aby brush. If you forget to clean it the filter is getting to be clogged which boosts the heat accumulation inside the machine. The cause of it is a higher consumption of energy and another possible technical issue.

The way how to remember the filter cleaning is the air filter alert. The unit gives you feedback when it’s time to do regular air maintenance.

Heating Function

Some models offer a heating function. You can enjoy the cooling effect during hot summer months and heating of your home in cold winter days.

It’s possible to use this function in two ways. Firstly, it’s good to use it as supplemental heating when you have another source of heating. The second possibility is to use it as a regular source of heat. I wrote about it more in unbiased the best window air conditioners with heating buying guide.

One thing you shouldn’t underestimate is the fact your window has to be open during the winter and gaps around the unit are filled by accordion side panels.

Also, if you want to let the window air conditioner unit on a sill during winter you should prepare the appliance for bad weather by using a cover. The average price for a cover is $20.


Usually, this function is used as an argument for those who suffer from allergies and the higher moisture in the air can worsen their symptoms. Unfortunately, it’s not so easy.

To work properly the dehumidifier has to be switched on more than half an hour. If your unit works longer you can be sure the moisture is removed from the air by this function. But the function is also dependent on the humidity of air during summer in your state. To clarify is some states the relative humidity is very high in summer months and you will need to buy a dehumidifier unit as a solution of the moisture air. It means there will be another cost and you should be prepared for this.

Air Direction Control

If you belong to people who love to enjoy a cold comfort but you don’t like it when the freezing air is blown behind your neck because you are sensitive you should focus on air direction control when you pick your machine according to our instruction on how to choose a window air conditioner.

The window units have adjustable louvers that allow regulating the direction of blowing air. It can protect you and your guests from sitting an unpleasant airflow. Choose a machine with this ability if you desire to install it in a room where more people are concentrated.

Remote Control

The remote control is very useful because the window AC unit is designed to be used in one room but it could a pretty large room. It would be very annoying to stand up always when you want to change settings of cooling or turn it on or off.

Function available on a remote can be limited by the level of your model. The average models offer to control the temperature and fan speed on a small display. The more expensive units provide the comfort of having more function without having to stand up when you want to switch a mode of cooling.

if you have a problem with losing a remote control very often you appreciate the magnetic hold.

Fan Speed Adjustment

The fan speed adjustment allows you to let your machine blow the air faster that means to cool the home faster. If you feel overheated and sweat and need to stand in front of the machine to cool you down you will love this function. Once, the desired temperature is obtained the higher speed isn’t required anymore. It’s possible to switch to a low gear to maintain the temperature. It saves energy.

Usually, cheap units offer low and high gear. The more expensive units provide the comfort of three or four gears low, medium, high and auto.

The higher gears are noisy than the lower ones. You can use the low speed for sleeping and auto speed to maintain the reached temperature.


Every window air conditioner has a thermostat and it’s a very important part of it. It helps you to set the temperature in a room and keep it by switching off and on the compressor. When you set the pleasant temperature the thermostat gives a signal to the compressor and it starts cooling until the temperature is obtained. When the temperature in a room has reached the thermostat gives a signal to the compressor to stop cooling. Once, the temperature rises again the thermostat allows the compressor to start working again.

There are some differences among all models. You can choose from a regular mechanical thermostat model or digital thermostat.

Cheap models offer mechanical thermostat. You have to set the desired temperature manually by using a rotary dial with a range of numbers from 1 to 7. Cheap models don’t allow you to set the accurate temperature e.g. 73 degrees Fahrenheit. You have to use your feelings to detect the pleasant number on a rotary dial.

More expensive units provide to set an accurate temperature like 72 degrees Fahrenheit by using a digital thermostat.

The Bottom Line

You don’t need to be a billionaire to stay cool during hot days in summer. The window air conditioner is a great solution with a perfect ration between price and performance. There are tons of reliable models with amazing functions that make your life easier.

Our ultimate guide on how to choose a window air conditioner walked you through all important aspects and factors that affect the starting cost, monthly cost, and maintenance. Now you know what you should focus on and what you shouldn’t overlook while trying to reveal the best machine for you. I have done the research about the best window air conditioners and put it in the review – go read it now.

Keep in mind that when you decide to spend money and buy a new unit it’s better to prefer quality and good customer service than a low price. Sometimes you find out it’s much better to spend a higher amount of money at the beginning of the process than let your bill skyrocket every month.

Think about what you are expecting from your new window AC unit and write all the requirements on a paper. You can maybe live without a programmable timer but not without remote control and sleeping mode because want to install the appliance in a bedroom. Everything in your plan plays an important role even the size of the room where the device should be install.

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