Air Conditioner Buying Guide
Make the right air conditioner choice with AjMadison.
Buying a New Air Conditioner?
Then the big question is – what type of room air conditioner do you need? The number of choices may surprise you: window air conditioners, thru-the-wall air conditioners, ductless split systems, packaged terminal units and portable air conditioners.
Today’s air conditioners are durable and high-performing, yet quiet. They come in various sizes with many convenience features, including trendy color panels to match your room. Start here to learn the basics about air conditioners designed to keep you cool when the weather gets hot.
Room Air Conditioner Vs. Central Air Units
There are a few advantages to installing a room air conditioner instead of a central air conditioning unit:
Ductless Split Air Conditioners
If you’d like to get the benefits of a central air conditioning system without the waste of duct space, install a ductless split system. The ductless split system (also called a mini-split, ductless split, or duct-free system) had at least one unit inside the home (this is the evaporator) and one outdoor unit (the condenser). Small tubes of refrigerant run from the outdoor unit to the indoor unit(s) – these are also known as line sets.
A single zone ductless split unit will normally cover one room – just make sure the BTUs are high enough to cool the square footage in the room.
If you want to cool more than one area, a multiple zone split system applies two, three, or four (depending on the model) indoor units to one condenser.
A ductless split system has to be installed by a certified HVAC technician.
Ductless Split Installation
There are several types of ductless split systems to choose from Wall Mounted, Ceiling Cassette, or Ceiling Suspended.
Wall Mounted Ductless
Wall-mounted ductless systems mount on an interior wall and may come with customizable front panels that look like picture frames or pieces of art. This option works well if you have rooms without exterior walls or windows. You generally need only a 2” clearance from the ceiling, so you’ll have lots of placement options.
Ceiling suspended ductless systems allow the unit to be hung from a high ceiling or require less than 9 ¼” above-ceiling clearance. This option works well in large rooms, additions, or workshops when a wall mount isn’t possible.
Ceiling Cassette Units
Ceiling cassette ductless systems mount flush with the ceiling so you only see the grille. This option works well for drop ceilings and rooms with at least 9 ¼” above-ceiling clearance.
Thru-the-Wall Air Conditioner
A thru-the-wall air conditioner is a good choice for cooling a room if you don’t want to sacrifice the window or the room doesn’t have one. Air conditioners installed into a wall are single, self-contained units that exhaust heat and humidity from the room to the outside. Louvers (located on either the back or the back and sides of the unit) bring in fresh air. The air runs through coils, which are cooled by the compressor-using refrigerant, and then the fan pushes the cool air back into the room. Some units double as room heaters.
This type of air conditioner fits through a hole in the exterior wall in order to vent to the outside. You must install a sleeve in your wall to support the weight of the unit. Sleeves are sold separately and should be purchased with the air conditioner to be sure you have the proper fit. It is also important to know the construction of your home and how thick or deep your wall is – this will help you determine what type of wall air conditioner you can purchase. If the wall does not have an existing hole, consider professional installation.
Packaged Terminal Air Conditioner
PTACs are single, commercial-grade, self-contained units installed through a wall and often found in hotels. But you can use a PTAC to cool rooms in your home – and in certain situations, its unique size and configuration can be your best choice – such as room additions, garage conversions or sunrooms.
PTAC units are beneficial because they can efficiently cool and heat a room from a single unit. To cool, the unit’s compressor pumps refrigerant to cool the coils, which attracts heat and humidity, that then exhausted to the outside. To heat, this functionality is reversed.
The standard size of a PTAC is 42” wide and has to be installed into an external sleeve with an exterior grille that are both sold separately. A professional best installs these units.
Portable Air Conditioners
Portable air conditioners are very versatile units that can be easily moved from room to room and are perfect for bedrooms, garages, even a dorm room. They have wheels and are compact (usually 2’-3’ tall). Condensation is either collected in a bucket, redistributed through a hole, or recycled through the air, but the hot air needs to vent to the outside. A hose, usually 3” to 5” in diameter, attaches to the air conditioner then vents through a window, sliding door, wall or ceiling.
Look for portable units that provide the convenience of cooling, dehumidification, and a fan one.
Most portable air conditioners come with an installation kit for your window or sliding door that is easy to install and remove. If you are choosing to vent your portable air conditioner through a wall or ceiling – a hole will have to
be made for the hose to vent to the outdoors.
Window Air Conditioners
Window air conditioners are single, self-contained units that exhaust heat and humidity from the room to the outside. They have louvers on the back and sides that bring in fresh air. The air runs through coils, which are cooled by the compressor-using refrigerant, then the fan pushes the cool air back into the room. Some window air conditioners have electric heat strips and a few have heat pumps that supply extra warmth in cooler weather.
This type of air conditioner is energy efficient and a good choice if you are cooling one or two rooms, but works best in a single room with a door that closes. Installing your air conditioner in the most centrally located window of a room will maximize cool air distribution. You will need to know the type of window and its width, height, and depth when wide open before selecting a unit. Make sure the dimensions of the unit you choose are smaller than the open window dimensions. The one downside to a window air conditioner is that it blocks the light. A low-profile unit is shorter and allows more window access.
Three Types of Windows:
Window Air Conditioners
A window air conditioner must be supported from the bottom with a bracket to the exterior wall, or on the sides with a window installation kit (or both). All window air conditioners come with a window installation kit that contains the mounting brackets along with accordions to block the excess space on one or both sides of the unit. If you are installing the air conditioner with a window kit, it’s important that you account for at least three to four inches for the accordions to fit. You can install the unit using the entire window kit (photo above left), using only one side panel or using no side panels. Use of the window kit may vary depending upon the size of the window and the size of the air conditioner.
Slider & Casement Windows
For tall slider and casement windows, you may need to purchase additional Plexiglas, wood, or another filler to seal the space above the air conditioner. Most people can install a window air conditioner without professional help, which means a lower upfront cost.
Understanding Chassis and Sleeves
A chassis is a framework that supports the guts of the air conditioner.
A sleeve is the metal device that holds the air conditioner in the wall.
A window air conditioner with a larger BTU capacity (usually 10,000 BTUs and up) is too dangerous to install in one piece because they are much heavier – so those units will have a slide-out chassis.
An air conditioner installed into a wall can have a slide-out chassis sleeve or a thru-the-wall sleeve. You must have a sleeve if you are installing an air conditioner thru-the-wall because the wall itself cannot support the weight of an air conditioner. The sleeve also provides a tight fit, keeping unwanted drafts out when the unit is not in use.
Thru-the-wall sleeves are a more robust application designed for larger air conditioners installed into a wall, including PTACs. These air conditioners are rear-venting and are ideal for thicker walls.
Thru-the-wall air conditioners and PTAC units do not come with a sleeve. The sleeve is sold separately. Most sleeves come with an exterior grille, but for some models, you can choose special grille options for a different look.
Plugging It In
Check the power supply. What kind of plug does the unit have? What kind of plug is your wall outlet? Make sure the circuit can handle the operation of the unit.
Energy Efficient Air Conditioner
ENERGYSTAR® qualified room air conditioners use about 10% less energy than other models and have higher EERs and SEERs.
What’s an Energy Efficiency Ratio (EER)?
EER measures the efficiency of an air conditioner when it is 95 ° F outside by dividing the BTU/hr of cooling output by the watts consumed. This ratio tells you the amount of electricity an air conditioning unit requires to provide the desired cooling level. Air conditioners’ EERs usually range from 8.2 to 10.5. A model with an EER of 10 should use the 20% less energy than one with an EER of 8. Air conditioners with a higher EER usually have a higher price tag, but cost less to run.
What’s a Seasonal Energy Efficiency Ratio (SEER)?
SEER is used to measure a central of ductless air conditioning system’s efficiency over an entire theoretical cooling season. The higher the SEER, the more efficient the system. All air conditioners must have a SEER rating of at least 10 to be sold in the United States.
Air Conditioner Size
What Size Area Will You be Cooling?
A simple method to determine the square footage of the area is:
Multiply Length x Width = Area
(ex. 12’x15’ = 180 square feet).
Multiply Area x 30 = BTUs needed
(ex. 180’ x 30= 5,400 BTUs)
Consider whether the room has a door that closes or is part of a larger area. If you need to cool combined living areas – living room, dining area and kitchen, make sure you consider the entire space, as well as the height of the ceiling. It is usually better to use at least two air conditioners rather than one large unit for better cool air distribution.
Here is a Quick Calculation Guide based on circumstances that can adjust the size of the unit you’ll need:
More Air Conditioner Features
Cool Convenience Features
Easily select options with the touch of a button – often an LED Display.
Hi-tech models allow you to access units remotely from your computer or smartphone – turn them on and off or adjust temperature and more.
Make adjustments to temperature, timer, and fan speed without getting out of your seat.
Choices in controlling the temperature of the room provide greater comfort, saves energy and money. Check out energy-efficient units with a 24-hour programmable timer of sleep mode settings.
Look for adjustable louvers that allow automatic 2-way air swing for more even air distribution; 4-way airflow control that lets you direct air where you need it most.
Provides an additional heat source using heat strips or a heat pump for added warmth in the cooler months.
Permanent, anti-microbial filters clean the air removing harmful bacteria and allergens. Some models have a clean filter alert that notifies you when your filter needs to be cleaned.
Select a model with a really low fan speed for less noise, as low as 30 dBA.
Air Conditioner FAQs:
What is the correct capacity?
The cooling capacity of an air conditioner is measured in British Thermal Units. BTUs are the best indicator of the size of air conditioner you will need – the larger the area you want to cool, the more BTUs are required. Room air conditioners range from 5,000 to 24,000 BTUs. Bigger isn’t always better – a unit that’s too small for your room won’t cool enough, and one that’s too large may not be able to remove enough humidity to keep the room comfortable. As the BTU rating gets higher, so does the size, weight, and cost of the air conditioner.
What is the difference between manual and electronic controls?
Manual controls will have a knob where you set the temperature to low, medium, or high. Electronic controls have a touchpad and a digital display which allows you to set the unit to a specific temperature. The unit has to have electronic controls for use of remote control.
Could you explain the difference between electric heat and a heat pump?
When a unit says that there is electric heat there is a heat strip in the unit that uses the fan to distribute the heat. Electric heat is meant to subsidize an existing heat source. A heat pump function is similar to an air conditioner, however, instead of cooling the air as it would in the summer it heats the air and redistributes it into the room. It often will not work when it is colder than 40 degrees (except some PTAC and Ductless Splits) outside, but some units have electric heat backup. If heat is very important to you a PTAC or Ductless Split unit could be your best choice. Please look at the air conditioner description or call us at 1-800-570-3355 to talk with an air conditioning expert.
What does Energy Star mean?
Energy Star is a government-backed program that tests products' energy efficiency. Products that meet strict energy efficiency requirements determined by the EPA and the US Department of Energy are labeled as Energy Star.
What are EER and SEER Ratings?
The higher the Energy Efficiently Rating (EER), the more efficient the air conditioner. The EER of an air conditioner is determined by how many BTUs per hour are used for each watt of power. Air conditioners with a higher EER usually are accompanied by a higher price tag but cost less to run. Seasonal Energy Efficiency Rating (SEER) is commonly used to measure central and ductless air conditioning. All air conditioners must have a SEER rating of at least 10 to be sold in the United States. Air conditioners that are Energy Star have higher EERs and SEERs.
What is a chassis? What is the difference between a fixed chassis and slide-out chassis?
A chassis is a frame that supports the guts of an air conditioner. When the air conditioner is described as a fixed chassis, the chassis does not slide out – these air conditioners are for window installation only. Air conditioners with slide-out chassis can be installed into a window or a wall. They are easier to repair because the inside of the machine is easily accessed by sliding out the chassis.
How do I determine the noise level?
All air conditioners will make some sort of noise however the air conditioners on the market have been engineered to be quieter than older units. Friedrich air conditioners are known to be the quietest room air conditioners in the industry. Ductless split air conditioning systems are the quietest type of air conditioner since the compressor is outside the home.
What are airflow and output options?
This determines how you can move the vents to determine where the air flows in your room. Air deflection means that you can move the vents to the side and up and down manually. Air swing means that the vents move electronically.
What are fan settings?
Air conditioners come with many levels of setting some just come with two settings (on and off) or with more like low, medium, and high.
How do I determine my plug type or how many volts I need?
Your plug type will let you know how many volts you need. You can compare your outlet to see how many volts you need and also what type of plug your air conditioner requires.
What are the pros and cons of a window air conditioner?
Window air conditioners require very little installation and you can normally install them yourself so there is a low upfront cost. They are a good choice and are energy efficient if you are cooling one or two rooms and there are many to choose from.
Most window air conditioners are quiet but, since the whole system is contained in one unit they can be louder than split type air conditioners where the compressor sits outside. Window air conditioners obstruct at least part of one window and you need to either remove them or winterize them for the colder times of years.
How do I install a window air conditioner?
All window air conditioners come with a window installation kit which most people can install without professional help by sliding the unit into their window. Units with larger BTU capacity (usually 10,000 BTUs and up) are too dangerous to install in one piece because they are much heavier – these units will have a slide-out chassis. A chassis is a framework that supports the guts of the air conditioner. The chassis is designed to slide away from the back of the unit, which is called a sleeve. You remove the chassis and install the sleeve into the window. Then, you secure a bracket supporting the sleeve to the exterior wall. After the back of the unit is secure, you slide the chassis back into the sleeve.
Can a window air conditioner go through a wall?
Depending on the thickness of your wall, air conditioners with a slide-out chassis can go through a wall. You may need to install brackets to support the sleeve within the wall. You must check the thickness of your wall and the depth from the edge to the louvers of the air conditioner.
If your wall is too thick it can block the side louvers from venting properly which will cause your unit to burn out over time. Then you need to look into a rear-venting through-the-wall air conditioner with a separate wall sleeve to ensure it will fit into your wall and vent properly.
Do some window air conditioners have heat?
Yes. There are two different types of heat. Some window air conditioners have electric heat strips and a few have heat pumps.
What are the pros and cons of a through-the-wall conditioner?
A through-the-wall air conditioner is a good choice for cooling a room if you don’t want to give up the window or a particular room doesn’t have a window. They are reasonably energy-efficient and have a large range of capabilities. If you do not have an existing hole in the wall the unit can require professional installation.
What is an air conditioner sleeve, and do I need one?
A sleeve is the metal device that holds the air conditioner in the wall. You must have one if you are putting an air conditioner through a wall because the wall itself cannot support the weight of an air conditioner. An air conditioner installed into a wall can have a slide-out chassis sleeve or a through-the-wall sleeve. Slide-out chassis air conditioners come as one unit (the sleeve and the chassis) and vent through the sides and back of the unit. They can be installed into a window or wall, and are ideal for walls around 8 – thick or less. Learn more about installing a slide-out chassis air conditioner into a wall. Through-the-wall sleeves are a more robust application – these air conditioners are rear-venting and are ideal for thicker walls. Sleeves do not come with through-the-wall air conditioners; you must purchase the sleeve separately. Most sleeves come with an exterior grille, but for some models, you can choose different grille options for a different look.
How do I choose my PTAC unit?
The two most important things to keep in mind are BTUs and plug type.
BTUs are units of power – the larger the area you need to cool, the more BTUs you need. To calculate the BTUs you need use our BTU calculator. It’s important to find the right size. Buying a higher BTU air conditioner than your room size requires is not recommended. It is preferred to have the correct size air conditioner run for longer to properly remove humidity from the room.
There are two parts to plug type: voltage and amperage. As a general rule the higher the amperage the higher the heating capacity. PTAC units can be plugged into a receptacle or the unit can be permanently connected (hard-wired) to the building’s wiring. To hardwire your PTAC you will have to purchase a permanent connection kit (also called a sub-base kit) separately. If you are replacing an existing unit, choose a PTAC with the same plug type to determine the right amount of amperage and voltage.
What are the pros and cons of a PTAC unit?
PTAC units are beneficial because they can efficiently cool and heat a room from a single unit. PTACs are commercial grade durable units, but since they are units 42″ wide you have to have a large hole cut into your wall. PTACs have to be installed into an external sleeve with an exterior grille that are sold separately. PTAC units are generally more expensive than window air conditioners, but if you are planning to both cool and heat a room then you could save up to 20% a year on electricity.
How do I install my PTAC unit?
PTAC units are installed through a hole in the wall. Often you will need a professional to help install the unit, sleeve, and grille. PTAC units cannot be installed without a sleeve because a wall is not strong enough to support the weight of the unit.
How does the heater in a PTAC work?
PTACs can have two types of heat: heap pump or electric heat.
The heat pump reverses the cooling cycle on the air conditioner. The refrigerant is used to heat the coils, and after the air passes over the hot coils the heated air is pushed back into the room. This type of heat will work up until it is 40 degrees Fahrenheit outside and is ideal for warmer climates. Most PTAC units with a heat pump will come with electric heat back up for cooler winter temperatures.
Units with electric heat will have an additional heating element near the vents that is heated using electricity. The air is heated when it passes over the element. Units with electric heat generally last longer than the heat pump types and are quieter, but are not as energy efficient.
What types of accessories do I need to install a PTAC unit?
All PTAC units require purchasing a grille and a sleeve (unless you are replacing an existing model and your sleeve and grille are still in good shape). Other accessories such as drain kits, hard wiring connections, remote controls, and wall thermostats are also available and are usually sold separately.
How do I choose a portable air conditioner?
There are four things you need to consider when choosing your portable air conditioner: BTUs, plug type, water removal system and special features.
BTUs are units of power – the larger the area you need to cool, the more BTUs you need.
There are two parts to plug type: voltage and amperage. Most rooms have circuits rated for a total of 15 amps of electricity, and many units have common 125V/15A plugs that can be used in most homes. If you are installing a larger unit with higher than 15 amps and more than 125 volts you may need to call an electrician to upgrade your circuitry. If you are replacing an existing unit, choose an air conditioner with the same plug type to determine the right amount of amperage and voltage.
Most units will have a self-evaporating system, so the water condensation is recycled back into the air. In units with a condensate pump, water collects in a tank and is pumped outside through a hose. For a few units, water will collect in a tank that has to be manually drained every 2-6 hours depending on the size of the tank and the humidity in the air.
Many portable air conditioners are also dehumidifiers – meaning they not only cool the room but they also remove excess moisture from the air. Other models of portable air conditioners both cool and heat.
What are the pros and cons of a portable air conditioner?
Portable air conditioners are very versatile units that can be easily moved from room to room. Although the unit is required to vent to the outside, the venting application is more flexible – you can vent through a window, sliding door, wall, or even a ceiling. Some models have condensation buckets or trays that will need to be emptied for the air conditioner to work properly. If the unit has a self-evaporating system, the bucket would only need to be emptied under certain conditions when the water cannot be recycled fast enough back into the air. In this case, the compressor would shut off and an indicator light would alert you to empty the bucket. If the unit does not have a condensate pump or a self-evaporating system, the bucket will have to be emptied every 2-6 hours depending on the humidity in the air.
What is the difference between a commercial and residential air conditioner?
Commercial portable air conditioners are designed to run 24 hours a day – they are ideal for a computer/server room that needs to be cooled non-stop. Commercial portable air conditioners ideally have higher BTUs than residential units. Residential portable air conditioners have between 6,000 and 14,000 BTU, while commercial portable air conditioners will have between 6,000 and 60,000 BTU.
What type of drainage is required?
There are three ways that water is drained from a portable air conditioner:
With a self-evaporating system, the water is dispersed back into the air, so no drainage is required. Under extremely humid circumstances – the collection bucket may need to be emptied manually, but the compressor will automatically shut off and an indicator light will inform you to empty the tank.
If you purchase a condensate pump, the excess water will be pumped out of the tank through a hose to the outside. Additional installation is required.
Some models will require you to manually empty the water collection tank. This will need to be done every 2-6 hours depending on the humidity levels in the room.Explore Air Conditioners